Board of Contract Appeals General Services Administration Washington, D.C. 20405 _______________________________________________ GRANTED: March 2, 2000 _______________________________________________ GSBCA 14477 J.E. DUNN CONSTRUCTION COMPANY, Appellant, v. GENERAL SERVICES ADMINISTRATION, Respondent. Christopher J. Daus of Greensfelder, Hemker & Gale, P.C., St. Louis, MO, counsel for Appellant. Ruth Kowarski, Office of General Counsel, General Services Administration, Washington, DC; and Michael T. Brincks, Office of Regional Counsel, Kansas City, MO, counsel for Respondent. Before Board Judges BORWICK, PARKER, and WILLIAMS. BORWICK, Board Judge. Appellant, J.E. Dunn Construction Company (J.E. Dunn), on behalf of its subcontractor, NGG Ltd., Inc. (NGG), seeks $199,308.04 as damages for changes in the design of the north and south curtain walls of a construction project due to allegedly defective specifications in Government drawings. The construction project involved is what is now known as the Charles E. Whittaker Federal Courthouse, Kansas City, Missouri (the courthouse or project). We grant the appeal. We conclude that the curtain wall drawings were design specifications, that the Government warranted the sufficiency and adequacy of the specifications, and that the design specifications conflicted with the deflection specifications of the contract. We conclude that appellant and NGG relied upon the defective specifications in bidding the job. We conclude that the defect was latent and not reasonably discoverable by appellant or NGG before bid submission. We conclude that appellant incurred additional costs, which have not been paid, in correcting the defective design. Appellant has proven quantum of $199,308.04, and we award that amount plus interest due under the Contract Disputes Act of 1978, 41 U.S.C.  601-613 (1994 & Supp. III 1997). Findings of Fact Entitlement The parties and other firms in this appeal 1. J. E. Dunn, the general contractor for the construction of the project, is engaged in the general contracting business in Kansas City, Missouri. Stipulation  1, 8. NGG, a subcontractor to J.E. Dunn on the project, is engaged in the glazing and glass curtain wall fabrication and construction business. Stipulation  2, 10. The joint venture of Ellerbe Becket, Inc. and Abend Singleton Associates, Inc. (ASA) were the project architects; the joint venture prepared the specifications and drawings for the project. Stipulation  3. Cygna Project Management was the construction manager for the GSA. Stipulation  7. Heitmann & Associates (Heitmann) is an architectural cladding consultant engaged by J.E. Dunn. Appeal File, Exhibit 51. The building 2. It will be useful for an understanding of the issues in this appeal to describe the architectural features of the courthouse. The courthouse looks much like a cake with a wedge- shaped slice removed from its south side. Its north elevation consists of a circular plaza, fronted by six columns, approximately four stories tall. On top of the columns rests a semicircular glass curtain wall, reaching about three more stories to the seventh story. Above that, another semicircular cantilevered glass curtain wall rises to the penthouse of the building. Immediately in back of the edges of the curtain wall assembly, huge precast columns continue the circular shape of the structure, rising from the ground level to the penthouse. These columns frame the north elevation plaza, lower and upper north curtain wall assemblies. The tops of these columns jut toward each other across the top of the north curtain wall, covering about sixty percent of the north curtain wall's circumference. Board Exhibit 1 (photographs). 3. Immediately behind the precast columns are other elements, continuing to form a circle. One circular element rises from the ground level to the top of the building. The other sits on a rectangular structure which rises about four stories from the ground; that element also rises to the top. These elements continue around and form the most striking visual features of the south elevation, because they terminate with precast panels from ground level to the top of the building at forty-five degree angles to the main entrance of the building (framing the wedge-shaped slice). Board Exhibit 1. These panels are approximately thirty meters wide. Appeal File, Drawings, Amendment # 9, Drawing A301. The entrance, framed by these elements, consists of a wide stairway, a plaza, the front entrance of the building and, above the front entrance, a saw- tooth-shaped curtain wall. Board Exhibit 1. The solicitation Pre-bid cost reduction measures 4. On or about September 24, 1994, GSA solicited proposals for construction of the project based upon specifications and drawings prepared by Ellerbe Becket and ASA. Proposals were due on November 10, 1994. The cost range estimated by GSA for the project was between eighty million and ninety million dollars. Stipulation  14. GSA issued six amendments to the solicitation before the first bids were accepted. Appeal File, Exhibits 2-7; see Stipulation  1-26. The initial bids were opened on December 1, 1994; all bids exceeded one hundred million dollars, Appeal File, Exhibit 8, and the lowest initial bid for the project exceeded GSA's approximate ninety million dollar budget for the project. Stipulation  28. 5. On December 5, 1994, GSA issued amendment seven to the solicitation, requesting bidders to extend the time for acceptance of their bids and requesting bidders to submit suggestions for price reductions, which would be considered by GSA for purposes of revising the solicitation. Stipulation  29. Representatives of GSA, Ellerbe Becket and ASA visited each of the general contractors that submitted bids and interviewed them for suggestions on what items could be changed from the project to bring costs down within GSA's budget. Stipulation  30. 6. On or about January 5, 1995, Ellerbe Becket submitted a project memorandum to GSA outlining various cost-reduction items directed by GSA. Among the changes outlined was the deletion of the sawtooth design on the north facade and replacement of it with a simple segmented curtain wall system. Stipulation  32. As to that change, Ellerbe Becket recommended that GSA "change the stone/concrete horizontal bands on the north to metal panel spandrels (similar to the curtain wall on the south side of the building; reducing the weight of the system). This will make the SAWTOOTH one curtain wall system." Appeal File, Exhibit 92  11. A corollary to this recommendation was that GSA delete the sawtooth from the north facade and make the facade a curved/segmented facade. Id.  11a. Ellerbe Becket estimated the "cost reduction value" of the change to be $650,000. Id. 7. The solicitation and resulting contract provided in pertinent part: GENERAL REQUIREMENTS PART 1-GENERAL 1.01 DEFINITIONS A. General explanation: A substantial amount of specification language consists of definitions of terms found in other contract documents, including drawings; drawings are recognized as being diagrammatic in nature and not completely descriptive of requirements indicated thereon. Certain terms used in contract documents are defined in this article. Definitions and explanations contained in this section are not necessarily either complete or exclusive, but are general for the work to the extent they are not stated more explicitly in another element of the contract documents. Appeal File, Exhibit 1, Vol. I, vol. I at 01090/1 (Section 01090). 8. The solicitation and resulting contract also provided: 1.02 DRAWINGS AND SPECIFICATIONS A. The drawings (building elevations, floor plans, and design details) and specifications are an outline of the criteria and performance requirements of the work. The requirements shown by the details are intended to establish basic dimensions of the module and the sight lines, jointing and profiles of members. Within these parameters the Contractor is responsible for the design and engineering of the window system, including whatever modifications or additions may be required to meet the specified requirements and maintain the visual design concept for the entire project. B. It is recognized that the contract documents do not cover some conditions, or modifications which may be required. It is however, intended that conditions not detailed shall be developed through the contractorūs shop drawings to the same level of aesthetics and in compliance with performance criteria, as indicated for detailed areas and stipulated in these specifications. The contractor, by accepting a contract for the work, acknowledges this and agrees that the contracting officer shall make the final decision as to all matters whether or not detailed in the contract documents. 1.03 SYSTEM PERFORMANCE REQUIREMENTS A. General: Fabricate and install glazed aluminum window, curtain wall and entrance systems to withstand load from wind, gravity and seismic loads, movement of building structure and thermally induced movements as well as to resist deterioration under conditions of normal use including expos[ur]e to weather without failure. . . . . E. Anchoring System for Seismic Loading: Provide anchoring system, including connections to building structure, for glazed aluminum window, curtain wall and entrance system that is capable of sustaining forces generated by seismic loads, gravity loads, and stresses induced by thermal movement, acting separately or in combination, within the following parameters: 1. Connections and panel joints shall allow for a relative movement between stories of not less than 3 times the calculated interstory drift caused by design seismic forces or 13 mm, whichever is greater. Appeal File, Exhibit 1,Vol. I, vol. III at 08920/2, 08920/3. 9. The solicitation, as amended, and the resulting contract also provided: G. Provision for Movement of Structure: The glazed aluminum window, curtain wall, and entrance systems shall be designed to accommodate the following: 1. Interstory Drift: Floor-to-floor height at any floor divided by 400. 2. Deflection of Structural Frame: 3.175 mm maximum. 3. Deflection of north canteliver (outside grid line F): Allow for the following deflections in the cantilevered concrete structure of the north elevation. a. 27 mm maximum long term depiction (creep) at edge of structure at the mid-point between columns. ["b." is missing] c. 75% of the long term creep may be considered to occur simultaneously at each floor (25% differential). d. 10% maximum live load deflection at edge of structure at approximate mid-point between columns. e. As indicated on Drawing 2/A501A. 4. Deflection of south cantilever (inside grid line A): Allow for the following deflections in the cantilevered concrete structure of the south elevation: a. 13 mm maximum long term deflection at edge of structure at mid-point between corners. b. 75% of the long term creep may be considered to occur simultaneously at each floor (25% differential). c. 10 mm maximum long term differential deflection between corners and mid-point of wall. d. 6 mm maximum live load deflection at edge of structure at mid point between corners. e. As indicated on Drawing 3/501A. Appeal File, Vol. IV, Exhibit 42 (conformed specification of solicitation, division 8, section 08920) at 08920/5, 08920/6. 10. The contract also provided: PART 2- PRODUCTS . . . . 2.02 MATERIALS A. Aluminum 1. Provide sizes shapes and profiles, as shown for aluminum members. 2. Provide wall thickness, as required by calculation and good practice, to comply with structural loading and other performance requirements, but not less than the following: a. Principal extrusions: 3.2 mm min. thickness. b. Extruded Snap Type Glazing Stops and Miscellaneous Non-Supporting Trim Members: 1.6 mm min. thickness. 2.07 FABRICATION A. General 1. All parts of the work shall be of the materials, design, sizes and thicknesses shown or called for on the drawings and/or as herein specified or as may be required to meet the aesthetic intent and performance criteria. Appeal File, Exhibit 1, Vol I, vol. III at 08920-11, 08920-20. 11. The contract contained the standard form Changes Clause, FAR 52-243-4--CHANGES (AUG. 1987), which provided in pertinent part: In the case of defective specifications for which the Government is responsible, the equitable adjustment shall include any increased cost reasonably incurred by the Contractor in attempting to comply with the defective specifications. Appeal File, Exhibit 1, Vol. I, vol. 1 at GSA Form 3506 at 31 ( 80(d)). The contract also contained the standard form Equitable Adjustment Clause, GSAR 552.243-71--EQUITABLE ADJUSTMENTS (APR 1984). Id. at 31 ( 81). The contract drawings North curtain wall 12. As part of amendment nine, GSA issued new drawings for the north curtain wall. Drawing A302 shows a combination of precast concrete and stone cladding from the parking level to the service level. The drawing shows the north plaza, Finding 2, to be built primarily of precast concrete panels. Between the massive precast columns, Finding 2, is the glass curtain wall, which runs from level four to just beneath level six, and meets a portion of the precast column at its east and west edges at a ninety-degree angle. This section of the curtain wall consists of glass panes framed by sixty-three vertical mullions and eight horizontal mullions. Appeal File, Drawings, Amendment # 9, Drawing A302. The curtain wall above consists of glass panes framed by eighteen horizontal mullions and sixty-three vertical mullions and runs from just beneath level six as shown on the drawing through level ten to the penthouse. Id. This section of the north curtain wall is cantilevered, i.e., its front edge extends beyond the front edge of the lower curtain wall. Board Exhibit 1. This drawing included the note: "125MM DEEP MULLION CAPS (TYPICAL AT NORTH CURVED WALL FACADE)," but did not mention dimensions of the horizontal mullion caps. Appeal File, Drawings, Amendment # 9, Drawing A302. 13. Drawing A411, depicting the vertical sections of the upper portion of the structure, shows the cantilever of the upper curtain wall just beneath level six at elevation 321 650. The drawing also refers to detail two of drawing A514 for the window framing. Appeal File, Drawings, Amendment #9, Drawing A411. 14. Detail two of drawing A514 for the north curtain wall shows a single rail fully-captured curtain wall system. Transcript at 36-37. A fully-captured system is one in which the glass is held in place by an aluminum extrusion, instead of being held in place by a structural sealant as in a butt-glazed system. Id. Detail two of drawing A514 shows, in a profile (side view (id. at 458)), a typical aluminum horizontal mullion. The mullion consists of a rectangle with the front of the rectangle and the mullion cap forming a figure shaped like an "H." Appeal File, Exhibit 34, Drawing A514, Detail Two. The top of the "H" holds, by gravity, the bottom edge of the glass pane located above the mullion. Id.;Transcript at 522-23. The bottom of the "H" secures the top edge of the pane of glass located below the mullion. Appeal File, Exhibit 34, Drawing A514, Detail Two. 15. Drawing A514 contains the following notation in front and above the mullion: "HORIZONTAL MULLION CAP--TYPICAL." Immediately beneath the note and in front of the mullion are two parallel lines with the dimension "75 [mm] TYP." Appeal File, Exhibit 34, Drawing A514, Detail Two. The mullion is shown to be the same width as the mullion cap. Id. A scanned graphic of the window wall detail, reproduced from a larger version of the drawing submitted as Respondent's Supplemental Appeal File, Exhibit 43, is included as Appendix A to this opinion. 16. A co-owner of NGG testified that he interpreted the note on the detail to mean that the width through the whole system, not just the width of the mullion cap, was to be 75 mm. Transcript at 307-08. The detail also shows a dimension of 300 mm from the front of the glass pane to the back of the rectangular aluminum mullion. Appellant's project manager testified that the detail essentially called for a mullion with the dimensions of 300 mm depth by 75 mm width. Id. at 49. Respondent's architect testified that, in his view, the 75-mm note referenced only the mullion cap and that "what goes on beneath it is up to the contractor to determine." Id. at 637. South curtain wall 17. Drawing A511, detail two, depicts the typical wall details for the south elevation of the project and makes specific reference to detail nine of drawing A511. That detail shows a split rail joint. Stipulation  20. A split rail joint is made of two members, with a male/female extrusion interlock. Detail two of drawing A511 shows the split rail joint and a note to that detail states: "EXTRUSION INTERLOCK--ALLOW FOR DIFF. SLAB MOVEMENT/SPEC." Detail nine shows a larger depiction of the split rail joint and provides some, but not all, dimensions of the surfaces comprising the split rail. The precise length of the channel to hold the interlocking portion of the joint was not dimensioned, but the front surfaces of the joint were dimensioned at 35, 30, and 35 mm, respectively. Appeal File, Drawings, Initial Solicitation, Drawing A511, Detail Nine. From those dimensions, it is possible to develop easily the length of 70-75 mm for the channel where the interlocking part was to fit. Transcript at 479-80. NGG's co-owner testified that the dimensions on that detail provided the sight lines were "quite specific" and were, in his interpretation, design requirements. Id. at 185-87. Amendment nine did not significantly change the drawings or specifications relating to the south curtain wall system. Appeal File, Exhibit 34, Drawing A514. Deflection drawings 18. Amendment nine incorporated drawing AM(9) 2/A501A-A. Stipulation  40. Drawing AM(9)2/A501A-A showed live load and long term creep specifications, in millimeters (mm). Appeal File, Exhibit 44. This drawing showed movement at several grid lines. For example, at grid line eleven, the drawing showed a total of 37 mm of movement, 27 mm for long term creep and 10 mm live load deflection. Since the contract specification, Finding 9, assumes that seventy-five percent of the long term creep occurs simultaneously at each floor, the differential of twenty- five percent is the critical factor for determining roughly the amount of deflection the curtain wall must accommodate. Transcript at 502. To figure the amount of deflection, one would take twenty-five percent of 27 mm (6.75 mm) and add that to the 10 mm live load deflection to arrive at the total allowable deflection of about 16.75 mm. Id. Such a calculation would be a rough estimate since long term creep happens over time periods as long as several years. Id. at 496-97. Anyone seeking to arrive at a precise estimate of long term creep would need advice from a structural engineer as to what period of time would elapse and how much long term creep would occur during the time period. Id. at 499. Bid opening time and subcontractor bids 19. GSA issued amendment nine on or about February 27, 1995, and requested proposals no later than March 21. Stipulation  35; Appeal File, Exhibit 12. On March 9, GSA issued amendment eleven, extending the bid opening date from March 21 to March 30. Stipulation  43; Appeal File, Exhibit 13. Six companies submitted bids to appellant to act as subcontractor for the aluminum window, curtain wall and entrance systems work, on the project: Harmon Contract, Cupples Products, Flour Cities Architectural Metals, B.C. Industries, H.C. Sharp Co., and NGG Ltd. Appeal File, Exhibit 93; Transcript at 152-53. No subcontractor noted an inconsistency between the architectural details for the aluminum curtain walls and the vertical movement specifications of the contract. Appeal File, Exhibits 94-98; Transcript at 153-62. 20. NGG received its copy of amendment nine a few days after the issuance of that amendment. Transcript at 411. NGG had about one month to submit its subcontract bid to J.E. Dunn. Id. at 194, 333. NGG's co-owner testified that, given the extensive contract documentation, submitting a timely subcontractor bid was a challenge, requiring late hours and perhaps "pulling all-nighters" in assembling the bid. Id. at 331, 333-34. 21. NGG believed that the drawings for the curtain walls set forth design requirements and relied upon those drawings in preparing its bid to J.E. Dunn. Transcript at 187, 189, 411. NGG's preparation of the bid focused on estimating material and engineering costs based on the design documents and the assumption that any building movement had been factored into the design documents. Id. at 196, 198, 413. NGG was aware that building movement occurred, but when the design, shapes and profiles of aluminum members are provided in the contract, and the contract requires the contractor to engineer the aluminum members during the shop drawing phase, it is customary not to engineer the curtain wall at the time of bid submission. Id. at 197-98, 413, 438. Contract and subcontract awards 22. NGG's base bid to appellant for the fabrication and installation of the curtain wall system was $4,890,000. Appeal File, Exhibit 93. J.E. Dunn relied upon that bid in submitting its bid of $84,695,000 to the Government. Transcript at 162-63; Stipulation  45. In submitting its bid to the Government, J.E. Dunn also relied on the Government's drawings and specifications for the curtain wall system. Transcript at 163. On June 21, 1995, GSA accepted J.E. Dunn's bid of $89,614,074 (including certain alternates and options) for construction of the courthouse. On or about June 22, J.E. Dunn awarded a $4,077,563 subcontract to NGG for the fabrication and supply of the aluminum window, curtain wall and entrance systems work of contract section 08920. Appeal File, Exhibit 67A. J.E. Dunn also awarded to NGG an $889,629 subcontract for installation of the aluminum window, curtain wall and entrance systems. Id., Exhibit 67B. Shop drawings and discovery of a design problem 23. On or about October 4, 1995, before preparing shop drawings, NGG submitted preliminary extrusion drawings to J.E. Dunn for the architect's approval, maintaining that the drawings were an "accurate representation of what the [Government] architect has drawn." Appeal File, Exhibit 47; Appellant's Exhibit A-1; Transcript at 202. NGG submitted these drawings early in the production process because of the long lead time it takes metal manufacturers to produce aluminum extrusions. Transcript at 205. The north curtain wall detail extrusion drawing (detail A) matched the shapes and profiles of detail two of Drawing A514. Appellant's Exhibit A-1. There were slight dimensional differences in the width of the mullion. The extrusion drawing's mullion width was three inches or 76.2 mm instead of the 75mm width shown on A514 detail two. NGG's co- owner testified that the difference existed because "you're rounding off the metric system to an [A]merican standard." Transcript at 208. NGG submitted other extrusion drawings on or about January 11, 1996. These drawings were approved by Ellerbe Becket. Based on these approvals, NGG purchased dies for the extrusions and aluminum materials in December of 1995 and January of 1996. Appeal File, Exhibit 80; Transcript at 262-63. 24. On January 30, 1996, NGG submitted shop drawings to J.E. Dunn, which returned the shop drawings to NGG without action because NGG had failed to include structural calculations with the drawings. Transcript at 208-10; Appeal File, Exhibit 50. NGG had a disagreement with J.E. Dunn about the timing of submission of structural calculations with the shop drawings. NGG agreed to provide the shop drawings in phases with structural calculations attached. Transcript at 211. 25. Beginning on or about March 22, 1996, NGG submitted to J.E. Dunn its shop drawings together with structural calculations for the glazed window and curtain wall work on the project. Stipulation  53. With respect to the north building elevation, NGG's shop drawings depicted a fully captured curtain wall system with single-piece horizontal rails and a 7[6]mm width horizontal mullion. Stipulation  54. Shop drawing D2 depicts the head and horizontal mullions of the north curtain wall. The drawing shows a mullion width of 76 mm (1 mm more than the dimension specified on detail two of Drawing A514) and a depth dimension from the front face of the glass to the back of the mullion of 300 mm, which matches the dimension on detail two of Drawing A514. Appeal File, Exhibit 46, Drawing D2. Shop drawing D3 shows the sill and floor and anchor for the north curtain wall and shows the same dimensioned mullion. Id., Drawing D3. Both drawings match the size (except for the 1 mm difference) and shapes shown on detail two of drawing A514. Transcript at 442. As with the architectural drawing, the mullion shown on the shop drawing consists of a rectangle with the front of the rectangle and the mullion cap forming a figure shaped like an "H," the bottom part of which secures the top edge of the glass pane. See Appeal File, Exhibit 46; compare id. with id., Exhibit 34, Drawing A514, Detail Two. For the mullions near the vertical anchoring of the floor line, NGG had engineered a 13-mm vertical splice into the mullion to accommodate some movement. The addition of the splice, however, kept the design concept shown in the architect's drawing. Appeal File, Exhibit 46A, Drawing 53; Transcript at 215. 26. For the south building elevation, NGG's shop drawings depicted a butt-glazed curtain wall system that included split horizontal rails. Stipulation  55; Appeal File, Exhibit 46B, Drawing D31. The mullion shown on the shop drawing matched the size, shape and profile of the mullion shown on detail nine, Drawing A511. Transcript at 217-19; Appeal File, Exhibit 34, Drawing A511. All shop drawings were marked "approved" by Ellerbe Becket. See Appeal File, Exhibits 46A, B. 27. On August 6, 1996, J.E. Dunn forwarded a copy of NGG's shop drawings and structural calculations to an architectural cladding consultant, Heitmann & Associates, for review of, among other items, the structural integrity of the north and south curtain walls. Appeal File, Exhibit 51. Heitmann soon reported to J.E. Dunn its tentative conclusion that, as depicted on the shop drawings, the north curtain wall would not accommodate the deflection criteria of the contract. Id., Exhibit 53. On August 16, Heitmann advised J.E. Dunn: The architectural and NGG drawings have been reviewed for their highlights (the more critical concerns, not a point by point check of details) and we consider this work complete for now. 1. The major finding is the design error by NGG in failing to provide for the specified vertical wall movements. The north elevation, above level 6, is particularly deficient. Correction to specification may involve changes in glass size, anchor design, and horizontal rail configuration. The south elevation, while also deficient, is manageable with relatively minor changes. Id., Exhibit 54. Heitmann spent about twenty hours of work diagnosing the problem. Id. 28. The north and south curtain walls as shown on NGG's shop drawings could not accommodate the deflection criteria of the contract. Transcript at 222. The problem with the design for the north curtain wall was that the bottom of the "H," formed by the 75 (or 76) mm mullion cap and the front of the rectangular extrusion, was not deep enough to accommodate the glass's possible vertical movement per the deflection criteria of the contract. Id. at 474. On the south curtain wall, the channels on the split rail as shown by the architectural and shop drawings were not deep enough to accommodate the specified range of movement. Id. at 478. Curtain wall redesign 29. On or about August 16, 1996, a meeting was held at the project site with GSA, Cygna, Ellerbe Becket, J.E. Dunn and NGG to discuss the alleged defects in the curtain wall drawings. During this meeting the participants examined several alternatives: (1) relaxing the deflection criteria; (2) deadloading the north curtain wall entirely off the seventh floor concrete structure instead of loading each floor as shown in the contract documents; (3) changing the horizontal rail on the north curtain wall to a split rail design; and (4) for the north curtain wall, increasing the horizontal mullion width. Transcript at 225-27. The Government, through Ellerbe Becket, rejected alternative one due to the cantilevered condition of the north slab. The Government, again through Ellerbe Becket, rejected alternative two after the deadloads for the seventh floor curtain wall were referred to a structural engineer, who determined that the seventh floor slab could not support the load. Redesign, either (3) or (4), or a combination of (3) and (4), were the only alternatives. Appeal File, Exhibit 27 at 003; Transcript at 227. 30. On September 5, 1996, NGG and J.E. Dunn submitted request for information (RFI) 626 to Ellerbe Becket. Stipulation  56. The RFI requested permission to enlarge the horizontal mullions on the north curtain wall from the seventh through tenth floors to a width of 143 mm. NGG submitted sketches which it maintained showed that 143 mm was the minimum mullion width that could accommodate the specifications for the placement of the glass and the full deflection criteria in the contract. Appeal File, Exhibit 21. Ellerbe Becket "approved" the sketch, but as the architect testified at the hearing, the approval was for the aesthetic concept only and was not authorization to proceed with the redesign. Transcript at 704. Although GSA's architect recommended approval of this solution to GSA, GSA decided that the solution would not meet requirements and decided not to accept it. Id. at 821. 31. On September 25, 1996, J.E. Dunn and NGG submitted RFI 659 to Ellerbe Becket, requesting approval of redesigned profiles for the north curtain wall, levels seven through ten, and the south curtain walls, levels four through ten, as shown on attached sketches. Appeal File, Exhibit 21. Ellerbe Becket viewed RFI 659 as an alternative proposal to the design solution of RFI 626. Transcript at 708. This solution showed the north curtain wall mullions in a split rail configuration with the mullion cap riding on top of the upper split rail. Appeal File, Exhibit 21 at 4. For the south curtain wall, NGG proposed to enlarge the front leg by 16 mm and the south leg by 33.4 mm to handle the movement criteria. Id.; Transcript at 236-37. 32. On November 4, J.E. Dunn and NGG provided GSA with Submittal 8920-004-P7, which consisted of shop drawings reflecting the approved profiles for the north and south curtain walls. Stipulation  59. Shop drawing D70 showed a split rail design for the north curtain wall mullions. The top element of the split rail was 76 mm wide, with a 29.8 mm gap between the upper and lower elements of the split rail system, and another 10 mm to the bottom edge of a visual element on the front top edge of the lower element. Appellant's Exhibit A-6; see infra Appendix B. The dimensions shown on the drawing were those that would exist without building movement, or the "nominal shape" of the mullion. Transcript at 242. Shop drawing D31 showed the split rail system with revised dimensions and shapes and sizes of aluminum members; the female member of the extrusion was made deeper by 19mm and reinforcements were added to the interlocking portion of the split rail. Appeal File, Exhibit 81 (Shop Drawing D31); Transcript at 245-47. 33. On November 29, 1996, J.E. Dunn and NGG submitted shop drawings (submittal 8920-004-P8) showing slight relocation of the horizontal mullions on the north elevation from level six and above so the existing glass could be used. On December 19, Ellerbe Becket, acting as architect for the project, indicated its approval of these shop drawings. Stipulation  60. J.E. Dunn and NGG submitted structural calculations for the redesigned north curtain wall system on December 16, and those calculations were approved by Ellerbe Becket and GSA on January 14, 1997. Appeal File, Exhibit 88; Transcript at 239. 34. After GSA's approval of the design solution proposed in RFI 659, NGG completed the drawings and ordered fabrication of new dies and extrusion. Prior to full fabrication, NGG constructed a mock-up for approval of the architect and GSA. Transcript at 248; Appellant's Exhibit A-3 (photographs). Quantum 35. The quantum for the north curtain wall redesign comprises the following elements: Engineering Cost Drafting: 260 Man Hours @ $50 per Hour $13,000.00 Independent Engineering: 60 Man Hours @ $65 Per Hour $3,900.00 Printing And Publishing: 10 Sets @ $250 Per Set $2,500.00 Subtotal $19,400.00 Fabrication Labor 248 Pieces x2=496 Joints @ 5 Minutes Per Joint=41.3 Man Hours @ $40 Per Hour ($1,652.00 ) 248 Pieces. x2=496 Joints @ 5 Minutes Per Joint=41.3 Man Hours @ $40 Per Hour ($1,652.00 ) Original Design Cutting Deduction ($3,304.00 ) Revised Design Cutting 248 Pieces x2=496 Joints @ 5 Minutes Per Joint=41.3 Man Hours @ $40 Per Hour $1,652.00 248 Pieces x2=496 Joints @ 5 Minutes Per Joint=41.3 Man Hours @ $40 Per Hour $1,652.00 248 Pieces x2=496 Joints @ 5 Minutes per Joint=41.3 Man Hours @ $40 per Hour $1,652.00 Revised Design Cutting Cost $4,956.00 Notching And Coping 62 Vertical Across North Elevation, 4 Levels Causing 428 Conditions @6.74 Hours=1,671 Man Hours at $40 per Hour $66,860.00 Total Additional Labor and Engineering for North Elevation Revised Design $87,912.00 Appellant's Exhibit 4 at 4. The north elevation materials quantum is $43,504.99, comprising $38,343.10 for aluminum dies and freight, $4,960.99 for paint and $190.90 for isolators. Id. at 3. The total claimed cost for labor and materials for the north curtain wall redesign comes to $131,416.99. Appellant then submits the following table in its post-hearing brief for a summary of the claimed costs of the redesign of the north curtain wall: Revised Design Material/freight Cost $43,504.99 Revised Design Labor/engineering Costs $87,912.00 Subtotal $131,416.99 Mark-up 10% $13,142.00 Subtotal $144,558.99 Profit 10% $14,456.00 Grand Total North Elevation $159,014.99 Appellant's Post-Hearing Brief at 47. 36. NGG's extra costs are summarized in the damages summary submitted as Appellant's Exhibit 4. This summary was prepared by NGG's co-owner, who reviewed the original bid, reviewed the shop drawings and was involved in the installation phase of the curtain walls. Transcript at 168-69. As evident from his testimony, NGG's co-owner was personally involved in the redesign of the curtain walls and the purchase of additional material and services necessary for the redesign. Id. at 272-83. The damages summary is based on invoices, purchase orders, quotes, billings, and time cards. Id. at 262. The damages summary was entered into the record without objection from respondent, and the back- up for the summary was made available to respondent. Id. at 261. 37. Because the design of the north curtain wall changed from single to split rail, Findings 14, 32, 33, NGG had to purchase new aluminum for the redesigned horizontal mullions. Transcript at 271. NGG had already purchased aluminum for the north curtain wall as originally designed, but could not use the aluminum on this or any other project. Id.; Appellant's Exhibit 4 at 3. The redesigned aluminum members needed painting and additional isolators. Appellant's Exhibit 4 at 3; Transcript at 272. NGG incurred engineering costs for drafting the redesign of the curtain wall, independent engineering, and printing and publishing. NGG's own draftspeople spent 260 man-hours at $50 per hour. Appellant's Exhibit 4 at 4. These hours were based on actual time cards submitted by the workers and were costed directly to the job, not to overhead. Transcript at 272, 278. 38. NGG incurred additional fabrication costs for the redesigned north curtain wall. Appellant's Exhibit 4 at 4. As a result of the redesign, NGG had to make 496 cuts in each of three dies instead of 496 cuts in each of two dies, the labor figured into the original bid. The claim is for the extra. Transcript at 273. NGG's co-owner estimated it took his workpeople five minutes per joint or 41.3 man-hours per die at $40 per hour. Appellant's Exhibit 4 at 4. The figure of five minutes is based upon the experience of NGG's co-owner in supervising the performance of the work, which consists of unloading the dies from the stockpile, making identification marks, sawing and cutting the dies, and returning the dies to the stockpile. Transcript at 273-74. 39. NGG incurred costs for notching and coping. Appellant's Exhibit 4 at 4. Notching and coping was the process of cutting notches in the aluminum extrusions into the split rail systems to allow the two pieces to move smoothly. Appellant's Exhibit A-3 (photograph f); Appeal File, Exhibit 38 (attached sketch hand-marked "D69"); Transcript at 274-75. The process also involved placement of screwholds on the bottom rail of the split rail system so that the two interlocking pieces could line up properly. Appellant's Exhibit 3 (photograph f); Transcript at 252. NGG had to process sixty-two vertical elements of the mullions across the north elevation, four levels of 248 conditions at 6.74 hours each or 1,671.50 man-hours. Appellant's Exhibit 4 at 4. South curtain wall quantum 40. The redesign of the south curtain wall caused a change in horizontal aluminum members. The horizontal aluminum members already purchased for the south curtain wall could not be used on the project or any other project. Transcript at 276-78. NGG incurred additional aluminum costs and engineering costs. Id. at 278-79. NGG incurred the following additional material and labor cost for the south curtain wall: Aluminum Material Cost for 54 Pieces @27'6" 1,485 @ $1.84 per Foot $2,732.40 Die cost $1,530.00 Material Cost for 54 Pieces @27'6" 1,595 Ft. @ $2.55 per Foot $4,067.25 Die cost $625.00 Aluminum Angle 10 Pieces @ 21/2"x11/2"x1/8"x16' Long $288.10 Subtotal $9,242.75 Engineering Labor 23.25 Man Hours @ 40 per Hour $930.00 Paint 54 Pieces @27'6" 801.90 Total Square Feet of Painted Area at $1.04 per Square Foot $833.98 58 Pieces @27'6" 1914 Total Square Feet of Painted Area at $1.04 per Square Foot. $1,990.56 Total $12,997.29 Appellant's Exhibit 4 at 7. With markups, NGG claims the following: Subtotal $12,997.29 Mark-up 10% $1,299.73 Subtotal $14,297.02 Profit 10% $1,429.70 Grand Total North Elevation $15,726.72 41. J. E. Dunn incurred additional fully burdened labor costs of $6,192, consisting of coordination and shop drawing review. These costs were recorded as direct labor costs to the job, not to overhead. Appellant's Exhibit A-5; Transcript at 98- 100. Appellant claims the following total additional costs: NGG COSTS North Curtain Wall Total $159,014.99 South Curtain Wall Total $15,726.72 Less Bid Cost for 13 Mm Splice $-750.00 NGG Total $173,991.71 J.E. DUNN COSTS Direct Labor $5,147.00 Payroll Tax, Insurance and Wage Benefits $337.00 Overhead (2.65%) $145.33 Subtotal $5,629.33 Fee (10%) of J.E. Dunn Total $562.93 Subtotal $6,192.26 Commission (10%) of NGG Total $17,399.17 Subtotal $23,591.43 Occupational License .(07% of Combined Total) $138.31 Bond (.6% of Combined Total) $1,185.50 Builderūs Risk (.0058% of Combined Total 35 $401.09 J.E. Dunn Total $25,316.33 Total of All Costs $199,308.04 Appellant's Post-Hearing Brief, Exhibit A, as modified by Letter from J.E. Dunn to Board (December 14, 1999). Discussion Design versus performance specifications Appellant argues that the specifications and drawings for the sizes, shapes and profiles of the north and south curtain walls were of the design type, and that, as such, the Government warranted the adequacy and accuracy of those specifications. Appellant's Brief at 19. Appellant acknowledges that the contract's deflection criteria were performance specifications, but maintains that since the contract imposed design requirements on the sizes, shapes and profiles of the north and south curtain walls, it was the Government's responsibility to ensure that the specified design could accommodate the deflection specifications. Id. at 29. Respondent agrees that appellant's original design for the north and south curtain walls did not meet the deflection criteria. Respondent maintains that contract section 08920 placed the design responsibility on appellant, and that it was appellant's responsibility to determine the means and method of accommodating the building movement criteria in the design and engineering of the curtain walls. Respondent's Brief at 39. Respondent, relying on paragraph 1.01A of contract section 01090, states that the architect's drawings were merely "diagrammatic" and that "it is not reasonable to interpret this contract in a manner that compromises performance in favor of architectural detailing." Id. at 43. Respondent argues that the word "basic" in paragraph 1.02A of contract section 08920, and the phrase "in compliance with performance requirements" of paragraph 1.02B of that section meant that the drawings were only the starting point, to be modified at the discretion of the contractor to meet the deflection criteria. Id. at 44-46. Design specifications are explicit specifications which tell the contractor exactly how the contract is to be performed and from which no deviation is permissible, whereas performance-type specifications set forth only an objective standard to be achieved. Dewey Electronics Corp. v. United States, 803 F.2d 650, 658 (1986) (citing J.L. Simmons Co. v. United States, 412 F.2d 1360, 1362 (Ct. Cl. 1969)). The Government warrants the sufficiency and adequacy of its design specifications. United States v. Spearin, 248 U.S. 132 (1913); P.J. Dick v. General Services Administration, GSBCA 12132, et.al., 94-3 BCA  26,981, at 134,395; Concrete Placing Co. v. United States, 25 Cl. Ct. 369, 374 (1992); aff'd, 985 F.2d 585 (Fed. Cir. 1992) (table). Many specifications are mixed performance and design specifications. Whether particular specifications are of the design or performance type often turns on the degree of discretion the contract provides the contractor in meeting the specification. In Santa Fe Engineers, Inc., ASBCA 24469, 92-1 BCA  24,665, aff'd, Santa Fe Engineers, Inc. v. Kelso, 19 F.3d 39 (Fed. Cir. 1994) (table), the board considered whether drawings depicting the general, but not exact location of duct openings in floor slabs on a construction project were design or performance specifications. The board held the duct chase and web penetration drawings were performance specifications because no dimensions were given on the drawings, and the drawings did not show structural steel framing necessary to support the concrete surrounding the non-dimensioned openings. The board noted that the contract's written specifications specifically assigned to the contractor the responsibility for the proper size and location of sleeves and prepared openings. The contractor was, therefore, granted discretion on where to place the openings. Santa Fe Engineers, 92-1 BCA at 123,068. Conversely, and recently, this Board concluded that in constructing the Trenton, New Jersey Courthouse annex, the contractor was entitled to rely on GSA contract drawings for a metal stud backup wall system depicting spacing of studs every sixteen inches even though the spacing of the studs at that distance did not meet wind load specifications. We rejected GSA's argument, similar to the argument it makes here, that designing for wind load resistence was the contractor's responsibility. We concluded, "Nowhere did the specifications specifically state that despite what was shown on the drawings, metal studs at the windows and corners would need to be spaced significantly closer together than the sixteen inches shown uniformly throughout the drawings." SAE/Americon-Mid Atlantic Inc., GSBCA 12294, et. al., 98-2 BCA  30,084, at 148,914-15. The contractor was therefore entitled to recover for the added work and expenses associated with the defective specification. Id. Similarly, in Morrison-Knudson Co., ASBCA 32476, 90-3 BCA  23,208, at 116,479-80, the board held that Government drawings for a fuel system, powering radar sites in remote areas of Alaska, were design specifications because the drawings called out the exact dimensions for the fuel system and the configuration for the piping, including the elbows, the diameters of the supply lines, the return lines and the length of the respective lines. Having performed in accordance with those requirements, which were defective, appellant was entitled to an equitable adjustment for the time and cost of overcoming the defective design of the fuel system. In Leslie-Elliott Constructors, Inc., ASBCA 20507, 77-1 BCA  12,354, at 59,790, the board concluded that Government drawings for an automatic sprinkler system were primarily design specifications. Although pipe diameters were to be developed by the contractor, the drawings were definitive as to the number and locations of mains, branch lines and sprinklers, as well as to the length of the piping. In other words, the drawings defined the type of system to be used by the contractor and were not, as the Government argued, merely schematic or descriptive, showing only the overall picture or general scheme of the sprinkler system. Here, the specifications require the contractor to follow the drawings in building the project. Paragraph 1.02A of contract section 08920 provides that "the requirements shown by the details are intended to establish the basic dimensions of the module and sight lines, joint and profiles of members." Finding 8. The paragraph states that drawing details are "requirements." The specification continues: "Within these parameters the Contractor is responsible for the design and engineering of the window system, including whatever modifications or additions may be required to meet the specified requirements and maintain the visual design concept for the entire project." Id. (emphasis supplied). Thus, the contractor's discretion is confined by the requirements shown on the drawing details. Although the contractor may make modifications, any modification must conform to the details and maintain the visual design concept of the project, as well as comply with the contract's performance requirements. Other provisions of the specifications emphasize the binding nature of the drawing details. Paragraph 2.02A of contract section 08920 requires the contractor to "provide shapes and profiles, as shown" for aluminum members. Finding 10 (emphasis supplied). Paragraph 1.02B of contract section 08920 describes the contractor's responsibility for engineering systems and when it is to engineer systems: "It is however, intended that conditions not detailed shall be developed through the contractor's shop drawings to the same level of aesthetics and in compliance with the performance criteria as indicated for the detailed areas and stipulated in these specifications." Finding 8 (emphasis supplied). Drawing A411, which depicts the vertical sections of the upper portions of the courthouse, refers the contractor to detail two of Drawing A514 for the window framing. Finding 13. That detail shows a typical single-piece mullion, dimensioned at 75 mm x 300 mm, with the glass held in place by the front of the rectangle and the mullion cap. Finding 15. For the south curtain wall, detail nine of Drawing A511 shows a split rail mullion with the front surfaces dimensioned at 35, 30, and 35 mm, respectively. If the mullion is produced with those dimensions, the dimensions of the interlocking parts will follow. Finding 17. We thus cannot agree with the Government's argument that the drawing details were merely schematic, or that the written specifications subordinated the drawing details to the performance requirements. The argument may be an example of the wish being father to the thought, but it was simply not the way the contract was written. First, for the north curtain wall, the drawing specified the important design concept of a single rail, simple, fully captured curtain wall system. The mullions for the north and south curtain walls were dimensioned and considerably detailed in the drawings, leaving little discretion to the contractor as to how to fabricate the mullions. The written specifications explicitly state that the drawing details confine the contractor's discretion. The pre-bid and post-award actions of the Government make clear the importance of the architectural detailing. The courthouse is an architecturally complex structure involving the joining of different elements in interesting ways and at unusual angles. Findings 2, 3. The contract was written to ensure the implementation of the unique architectural vision. This explains the repeated references in the written specifications in contract section 08920 to the importance of "sight lines, jointing and profiles," "visual design concept" (paragraph 1.02A), and "aesthetics . . . as indicated for the detailed area" (paragraph 1.02B). Indeed, the sight line created by the 75 mm mullion width for the north curtain wall was so important that when the design problem eventually developed, the Government rejected a solution that would have increased the mullion width to 143 mm. Finding 30. Furthermore, the Government changed the design of the large north curtain wall from a sawtooth, split rail system to a simple fully captured system, in order to effectuate cost savings of about $650,000. Finding 6. The drawing details implemented the change and, therefore, the supposed cost savings. We agree with the Government that the performance specifications were important. The contract, however, required the contractor to comply with the design requirements in the drawing details and to use its ingenuity and skill in meeting the performance specifications. (Indeed, paragraph 1.02B, quoted above, suggests that if the contractor followed the drawing details it would be in compliance with the performance requirements.) As indicated in our findings, and as discussed below, the contractor could not produce north and south curtain wall mullions that met the design specification of the drawings and, at the same time, meet the performance requirements of the contract. The Government argues that paragraph 1.01A of contract section 01090 makes all drawings "diagrammatic." Diagrammatic simply means "being or relating to a diagram; . . . graphic." Webster's Third New International Dictionary at 622 (1986 ed.). The clause merely states that matters shown in a drawing "may not be completely descriptive of the requirements indicated thereon." Finding 7. The language certainly does not mean that what is described should be treated as superfluous or meaningless. In any event, the definitions and explanations in the clause are general for the work "to the extent that they are not stated more explicitly in another element of the contract documents." Id. The more explicit statements in this contract are the drawings themselves and the specifications in contract section 08920. The specific language of the contract takes precedence over the general language. J.S. Alberici Construction, Inc. v. General Services Administration, GSBCA 12386, 94-2 BCA  26,776, at 133,172. Defective specifications Both appellant and NGG relied on the Government's drawings in submitting bids. Finding 22. After the award of the contract, appellant and NGG acted cautiously and submitted sketches to Ellerbe Becket showing the anticipated design of the north and south curtain wall mullions. Appellant secured Ellerbe Becket's approval for the general design. Finding 23. The shop drawings for the north and south curtain walls were in accordance with Ellerbe Becket's drawings, save for a 1mm discrepancy--the mullion width was 76 mm instead of the specified 75 mm. The drawings proposed for the north curtain wall, in accord with the architect's drawings, showed a rectangular, single rail, fully captured curtain wall system. Finding 25. The engineered splice in some of the mullions was in keeping with the design concept shown on the architect's drawings and involved no change in the basic dimensions of those mullions with the splice. Id. The shop drawings for the south curtain wall matched the size, shape and profile of the mullion shown on detail nine of Drawing A511. Finding 26. Unfortunately, for the north curtain wall, with the 75 mm mullion width specification in the drawing, the functional bottom legs of the "H" shape at the front of the mullion holding the top of the glass panes in place were not long enough at 75 mm (or 76 mm for that matter) to accommodate the contract's deflection criteria. Findings 27, 28. At the south curtain wall, the depth of the interlocking channels resulting from appellant's producing a mullion in conformity with the Government's drawings was insufficient to accommodate the deflection criteria. Finding 28. In another parry to the appellant's case, the Government argues that the 75 mm mullion width was simply a cosmetic width to the mullion cap, and did not control what size mullion the contractor developed beneath. Finding 16. We disagree. Detail two of Drawing A514 showed a mullion size of the same width as the mullion cap. Finding 15. The drawing note of "75 mm" does not refer specifically to the mullion cap as distinguished from the mullion itself. The drawing seems clear to us as specifying a 75 mm width for both the cap and the mullion. Since both appellant and NGG relied upon the drawing in making up their bids, Findings 21, 22, any latent reasonable ambiguity on that point must be resolved in favor of the appellant and against respondent, on whose behalf the architect drafted the document. Fruin-Colnon Corp. v. United States, 912 F.2d 1426, 1431 (Fed. Cir. 1990); WPC Enterprises Inc. v. United States, 323 F.2d 874, 876-77 (Ct. Cl. 1963); International Fidelity Insurance Co., ASBCA 44256, 98-1 BCA  29,564, at 146,552. In any event, no matter what the mullion size would have been, in the single rail fully captured system shown on Drawing A514, the mullion cap itself, not the back of the mullion, had to be long enough to hold the glass in place throughout the range of possible deflection. The mullion cap was not merely cosmetic. Latent versus patent defect Appellant argues that the defect in the Government drawings was latent and not reasonably capable of being discovered before bid submission. The Government argues that the defect, if any, was patent, and that appellant was under a duty to seek clarification before it submitted its bid. A patent ambiguity or defect in the specifications does not exist where the ambiguity or defect is "neither glaring nor substantial nor patently obvious." Community Heating & Plumbing Co. v. Kelso, 987 F.2d 1575, 1579 (Fed. Cir. 1993) (citing Mountain Home Contractors v. United States, 425 F.2d 1260, 1264 (Ct. Cl. 1970)). In considering this issue, we must put ourselves in the shoes of a reasonably prudent construction contractor. M.A. Mortenson Co., ASBCA 39978, 93-3 BCA  26,189, at 130,367 (citing Hegeman-Harris & Co. v. United States, 440 F.2d 1009, 1016 (Ct. Cl. 1971)). Thus, we have considered an ambiguity "patent" where a "cursory examination" would have revealed inconsistencies in details of two drawings and where the inconsistencies could be resolved without reference to other drawings or the written specifications. American Commercial Contractors, Inc. v. General Services Administration, GSBCA 11713, et al., 94-3 BCA  26,973, at 134,355. The defect in this case was not patent or obvious. Six bidders submitted bids for the work covered by contract section 08920, and none of them noticed the supposedly "patent" defect. Finding 19. Not even the Government's architect discovered the defect during its initial review of the sketches NGG submitted before the submission of its shop drawings. Finding 23. After submission of shop drawings, it took a cladding consultant twenty hours of engineering study to discover that there even was a defect and its full extent. Finding 27. It took additional structural engineering to determine what design and what shape of mullion would accommodate the deflection criteria. Finding 35. In order to discern the discrepancy before bid, the contractor and NGG would first have had to ignore paragraph 1.02B of contract section 08920, which explicitly told the contractor to delay the engineering of conditions not detailed on the drawing until the shop drawing stage. Finding 8. The appellant and NGG would then have had to refer to Drawing AM(9) 2/A501A-KA, Finding 18, educate themselves on structural engineering concepts such as "long term creep" and "differential," and then roughly calculate deflection loads in accordance with the formula specified in the contract and conclude that the Government's design did not take into account those loads. Id. A reasonably prudent construction contractor is not expected to become an amateur structural engineer and hunt down defects in Government design drawings upon which the contractor has been told to rely, especially given the relatively short--one month--time to prepare bids. Jordan & Nobles Construction Co., GSBCA 8349, et al., 91-1 BCA  23,659, at 118,513. Quantum Appellant has established the existence of a latent defect in a Government design specification. Respondent cites the classic formula for an equitable adjustment--that appellant is entitled to the difference between the reasonable cost of performance without the added work and the reasonable cost of performance with the added work necessary to overcome the defective specification. Miller Elevator Co. v. United States, 30 Fed. Cl. 662, 701 (1994). The Government argues that appellant failed to present meaningful evidence concerning its reasonable costs of performance without the new curtain wall modification work. Respondent's Reply Brief at 13. There is a difference, however, between pricing changed work and pricing extra work separate from other work covered by the contract. The classic formula cited by respondent involves changed work. When the issue involves extra work, "the actual or reasonable cost may easily be determined and a profit factor added." J. Mc Bride & T. Touhey, Government Contracts, Vol. 4,  28.260, 28-415 (Release 402, Feb. 2000). Thus when the Government issued a defective design specifications for repair of air base runways, the contractor was "awarded all costs directly associated with the installation of the CT-2 sealant," with the recovery including "costs relating to all materials, extra labor, and additional equipment relating to the C-2 installation portion of the contract." Concrete Placing Co. v. United States, 25 Cl. Ct. at 375; see also Fireman's Fund Insurance Co., ASBCA 39666, 91-1 BCA  23,372, at 117,259 (quantum for extra paint flushing system installed to overcome design defect). Here, while the curtain wall designs were changed, the result was to impose extra work on the contractor and NGG. NGG had to start over and redesign the mullions, incurring new materials costs, new engineering costs and new labor costs. Thus, the claim is for the new items--the extra engineering and materials--caused by the Government's defective design. Findings 36-39. Appellant removed any original design costs from its claim. Consequently, while we have no cause to question the reliability of appellant's bid, the focus of the quantum must be on the reasonableness of the incurred costs for the additional work and materials. Respondent argues that the damage summaries are not evidence "sufficient to enable the Board to make a fair and reasonable determination of appellant's damages." Respondent's Reply Brief at 13. We disagree. Damage summaries are admissible under Fed. R. Evid. 1006, provided that the "originals, or duplicates shall be made available for examination or copying or both, by other parties. . . ." Boards have accepted such summaries as evidence of quantum provided the summaries were reliable. See Armada, Inc., ASBCA 27345, et. al., 84-3 BCA  17,694, at 88,243 n.3. Here, respondent had access to the underlying documents and the damage summaries were introduced without objection at the hearing. According to the unrefuted testimony of NGG's co-owner, the summaries are based upon NGG's actual material costs, actual engineering costs, and estimates of the time it took to machine the dies and mullions for the redesigned curtain walls. Finding 36. The summary was prepared by NGG's co-owner, who had an intimate familiarity with NGG's original bid and personal experience with the redesign effort, Finding 36, and whose testimony we find to be credible and trustworthy. Appellant has not presented perfect evidence of quantum, but perfection is not required. We consider the summaries reliable and satisfactory for a reasonable determination of damages. Respondent argues that it is entitled to a "credit for all costs incurred by NGG and [appellant] as a consequence of mistakes they admit should have been picked up by NGG during the engineering stage." Respondent's Reply Brief at 18. The alleged mistake to which respondent refers was NGG's co-owner's statement that he wished NGG had noticed the defect during the shop drawing process, instead of J.E. Dunn having to find the defect through use of a consultant. See supra note 11. This just serves to illustrate the latent nature of the drawing defects. Also, the Changes clause in this contract provides that "in the case of defective specifications for which the Government is responsible, the equitable adjustment shall include any increased cost reasonably incurred by the Contractor in attempting to comply with the defective specifications." Finding 11. The consultant cost was incurred to determine whether the original shop drawings met the deflection specifications. Finding 27. Appellant has proven damages of $199,308.04 and is entitled to an award in that amount. Decision The appeal is GRANTED. Appellant is awarded $199,308.04, plus interest in accordance with the Contract Disputes Act of 1978, 41 U.S.C.  611 (1994). __________________________ ANTHONY S. BORWICK Board Judge We concur: ___________________________ ____________________________ ROBERT W. PARKER MARY ELLEN COSTER WILLIAMS Board Judge Board Judge APPENDIX A APP END IX B