Companion files
Construction Cost Management and Contract Administration from the Contract Sum to the Final Account
These are the four Excel workbooks that go with the book. Every figure the book prints is reproduced in them by a live formula rather than a typed constant — change the design completeness, the provisional sums released, the weeks of extension of time or the escalation index, and every dependent number moves. Each one ends with a Checks sheet setting the printed figure beside the computed one: 242 controls in all, every one green. If a control ever reads FAIL, the workbook is wrong, not the book.
Free to download. No sign-up, no email address, nothing to fill in.
Chapters 1 to 11
The contract sum rebuilt layer by layer rather than asserted: measured works at 2,180 per m2 over 8,640 m2 of gross internal area, 18,835,200, then 1,240,000 of external works and site, preliminaries at 15.0 per cent, overheads and profit at 6.0 per cent, a contractor’s design development allowance of 2.0 per cent and 1,340,000 of provisional sums, arriving at 26,301,102, or 3,044 the square meter and 273,970 the apartment. Move the measured rate and every layer above it rebuilds, because each one is a percentage of the layer beneath it.
Then the eleven lines that carry Pemberton Yard to 29,153,363: a movement of 2,852,261, 10.8 per cent of the contract sum, split by formula rather than by hand into the building the client bought, 1,052,000, the price it lost, 2,030,500, and the money it recovered, 230,239 — of which the workings above the lines show 1,742,160, 85.8 per cent of the loss, standing on inputs that existed at signature. The same eleven lines run again for Case B, the same building bought with a complete design: 90,648 dearer at the contract, 1,620,289 cheaper at the final account, a return of 17.9 to 1. Two reconciliation cells sit under the totals and must read zero.
Chapters 12 and 13
The developer’s appraisal run six ways in six columns: both cases, each at the contract sum and at the final account, and the final account once more on the pessimistic reading where the facility is stretched to cover the overrun instead of the equity being called. On 45,312,000 of revenue, 6,200,000 of land and fees at 9.8 per cent of construction cost, Case A is underwritten at 17.40 per cent profit on cost and delivers 8.59: 3,131,783 of profit gone, 46.6 per cent of what was underwritten, to an overrun of 10.8 per cent. Case B is underwritten at 17.07 and delivers 13.40. Each column shows the construction cost being appraised above the construction cost the facility was sized on, so the stretched reading is visible rather than asserted.
Then the headroom, solved rather than searched for. Because fees are a percentage of construction cost and the facility is held where it was sized, revenue, land, finance and sale costs are all fixed at the target and the break-even falls out in five lines of rearrangement: the construction cost at which profit on cost is exactly 15.0 per cent is 27,033,648, which is 732,546 above the Case A contract sum, or 2.8 per cent. The gap ran to 2,852,261, 3.9 times the headroom. The sheet then proves its own answer by running the full appraisal at it and landing on 15.0000 per cent with a difference from the target of exactly zero, and a Solve sheet does the same arithmetic on your scheme, your target return and your contract sum.
Chapter 14
Six tables, each moving one input and leaving the contract sum where it is, because a table that re-priced the contract sum as the input moved would be a re-pricing and not a stress, and the gap would never widen. Design issued at contract, from 55 to 96 per cent, moves the movement from 3,450,778 to 2,388,052 and the gap from 13.1 to 9.1 per cent. Provisional sums released, from 1,340,000 to 2,600,000: 1,989,054 to 3,331,821. Extension of time, from 0 to 16 weeks: 2,439,045 to 3,011,087. Productivity loss, from 0 to 16 per cent: 2,563,921 to 2,983,325. Escalation, from 0.0 to 10.0 per cent a year: 2,714,778 to 3,055,699. And the post-award pricing premium, the input that moves the answer least, from 2,739,976 to 2,913,939.
The book prints the movement column. The workbook prints all eleven lines for every scenario, which is the difference between reading a sensitivity and understanding one; the row that matches the book is shaded in each table, and each table ends on its span. A Ranking sheet orders the six inputs by span, sets each span against the base gap, states in one line whether the client controls that input before signature, and closes by putting the largest single-input span beside the joint move that Case B represents and showing the joint move exceeding it. A seventh sheet carries design completeness through to the developer’s return, seven rows from 55 to 96 per cent and 6.90 to 9.93 per cent profit on cost, in which not one row clears the target.
Chapter 15 and Appendix B
This one does not reproduce the book. It is the instrument the book argues for, and it is meant to be used on a project that has not been signed yet. Type your own scheme in and the contract sum rebuilds layer by layer, then hands you two figures most tenders never publish: your time-related preliminaries per week, and the value that will be priced after signature. The Forecast sheet forecasts the five lines whose inputs exist before signature — design development beyond the contractor’s allowance, the provisional sums, the post-award pricing premium, the prolongation, and the escalation on all four — then lists the rest of the bridge and declines to forecast it, each declined row carrying a note saying why. What it produces is called a floor on the final account rather than an estimate of it.
It ships filled in with Pemberton Yard, so the Checks sheet can prove it reproduces the book before you trust it with anything of your own. Fed the book’s inputs, its forecast of the knowable gap comes to 1,742,160, which is exactly the figure Chapter 2 reaches by a different route; the verdict cell then reads that against the headroom of 732,546 and writes the answer as a sentence rather than a number. Overtype the blue cells with your own project and those checks will fail. That is the workbook working, not breaking.
| Blue text | an input — change it and everything recomputes |
| Yellow fill | an assumption that decides the answer rather than merely feeding it |
| Black text | a formula — do not overtype these |
| Grey text | a note |
| Checks sheet | the printed figure beside the computed one, the difference, a PASS or a FAIL, and the tolerance being applied |
A workbook that agrees with a book proves nothing on its own — the author wrote both. What the Checks sheets do is different: they force the model to reproduce a number that was printed before the model existed, from a formula rather than from the number itself.
On this book the discipline caught the liquidated damages line. The client recovers damages for the weeks the contractor is late less the weeks it carries an extension of time, at 14,500 a week and under a cap, and the model writes that as max(0, weeks late less weeks with an extension). Written the obvious way, as a MIN against the cap with no floor beneath it, the arithmetic runs on past zero the moment the extension exceeds the delay — and one of the sensitivity tables does exactly that, taking the extension of time from 0 up to 16 weeks against a delay of 14. At the top row the line changed sign: a 43,500 credit to the client became a 29,000 charge against it, a contractor paid damages for finishing early on time it had been granted, and the movement column carried the error without ever looking wrong.
The second thing the checks caught is smaller, and it is left in view rather than tidied up. Construction costs are carried between the workbooks rounded to the pound, as the book prints them, so a figure the appraisal rebuilds from a rounded input can land one pound from the figure on the page. Six do: five in the appraisal, on the finance line, the total cost, the profit and the profit lost to the gap, and one in the pre-signature workbook. None of the six is smoothed away by widening a percentage or nudging an input. Instead every Checks sheet carries a sixth column stating the tolerance it applies, one pound on the fifty money checks that are fed a rounded cost and eight decimal places on the other 192, and the difference column prints the pound. 236 of the 242 land on zero.
Where two readings of the same quantity are defensible, both are printed. The Case A final account returns 8.59 per cent profit on cost with the facility held at the amount it was sized on, and 7.99 where the facility is stretched to cover the overrun instead of the equity being called; Case B, 13.40 and 13.14. Neither column is the answer on its own, and the workbook does not choose between them.
The workbooks open in Microsoft Excel, LibreOffice Calc, Google Sheets and Numbers. They use no macros and no add-ins, so nothing needs to be enabled or trusted. If your spreadsheet asks to update links on opening, decline — there are none.
The other books with companion files. The full list of titles is on the author page.