Engineering & Construction

The brief has changed three times, the budget has not moved, and no one is sure which version of the drawings governs. The question is no longer how to design: it is what can still be held.

A project only becomes real once it is drawn, costed line by line and set against a schedule the site can actually hold.

Executable project

INTERFACES

Schematic

Where defects are born: the seams between trades

A building almost never fails in the middle of a trade package, it fails at the seam between two. Walk through the section: each point opens the trap, what we impose in the contract, and what we go and check on site.

Schematic section — neither a construction drawing nor a real building: the eight seams of an ordinary building, from the bottom of the trench to the parapet.

Hover a point, or step through them with the keyboard

External works ↔ structure

BetweenExternal worksStructure

The trap

The sewer invert is set on one datum, the ground slab on another. It shows up the day the pipe comes out above the slab, and the remedy is then paid for in demolition, not in pipework. Existing services, meanwhile, get found with the bucket at the bottom of the excavation: on a Friday, with no utility record, and nobody to call.

What we impose

One single datum for both packages, the surveyor's, its benchmark physically set on site and its reference written at the head of both specifications — never two systems everyone assumes agree. Penetrations through the substructure are described as watertight works — sleeve, gland, seal — in the contract of the package that pours the concrete, never in the one that pulls the pipe: the hole follows the formwork, not the pipe. Statutory notices and utility records are required, received and dated before the first excavation is opened, and that date sits on the programme as a milestone, not as an intention.

What we check

Joint survey of invert levels before backfilling: afterwards, the trench has to be reopened to prove anything at all. Then tightness tests and a CCTV survey of the runs, with the report filed into the as-built record. Compaction measured layer by layer against its target, with a signed test sheet — compaction claimed and never measured is the leading cause of trench settlement, and it comes due two years later, under a road already handed over.

That chapter is not improvised the night before submission: a technical memorandum that names its interfaces, their owner and their date scores before it has even been read in full.

One file handled end to end, stage by stage

Read, isolate the real package, measure, price, question, submit: six stages, and for each the deliverable produced and the fact that drove what followed. No client name, no site name.

REFERENCE · ONE FILE, END TO END

Design-build of a very high-end reception complex, in the restricted area of an international airport.

Morocco, 2026. Structural works and waterproofing package, seven-month contractual deadline, firm non-revisable price. The file arrived as a parent all-trades contract across three sites, inside which the real package — one site, two sub-lots — had to be isolated before writing a single line.

17documents read, from the specifications to the topographic plans
7months of contractual deadline, scheduled day by day
≈ 1,200 m²of net floor area, four quadrants around a circular patio
9questions put to the client before pricing

THE DELIVERABLE

The file's knowledge base

Two contractual tiers untangled: the parent contract (all trades, three sites, eighteen months, revisable price) and the real package (structure + waterproofing, one site, seven months, firm price).
Every fact tied to its document — specifications, administrative clauses, bill of quantities, descriptive estimate, architect's and structural drawings, fire and acoustic reports, network and level plans.
What the file does not say is marked "to be confirmed" rather than assumed: the water table, the roof steelwork, the fire rating of the structure.

THE FACT THAT DRIVES IT

The specifications described an eighteen-month contract; the package to be priced lasted seven. Reading both tiers avoided scheduling — and paying for — a site installation two and a half times too long.

TECHNICAL OVERVIEW · WHAT THE FILE IMPOSED

The facts that make the price, as the documents state them. That reading — structure, quantities, requirements, site, contract — is what separates a priced bid from a guessed one.

Principle diagram drawn for this page — not a drawing from the file. Dimensions read in the documents.

The structure, as the drawings describe it

Geometry: Single storey with a high ceiling (about six metres), partial mezzanine on two levels, roof terrace; footprint of about 40 × 33 m, four quadrants around a circular patio; close to 1,200 m² gross floor area. No basement, no typical floor.
Foundations: Isolated footings of 1.80 to 2.80 m on 40 to 65 cm, perimeter strip footing, mass-concrete blocks and four localised 60 cm rafts under heavy zones; 10 cm blinding; allowable soil pressure of 1.8 bar.
Seismic: Zone 2, class III, site S2: tie beams from 30 × 40 to 30 × 65, sixty-diameter laps.
Superstructure: Columns-and-beams with 30 cm façade walls, 15 cm shear walls; columns from 30 × 40 to 30 × 100; beams up to 30 × 85 over an 8.30 m span; solid slabs of 20 to 27 cm; 13 cm slab on fill compacted to 96%.
Hard points: Two- and three-metre parapets in 25 cm walls, a cantilevered façade to prop for a long time, a fifteen-metre circular terrace, two offset floor levels, an expansion joint, a pit at −4.15 m and a services gallery at −3.00 m under ground that only goes down to −0.73 m elsewhere.

≈ 800 m³of structural concrete — 371 m³ of solid slabs, 263 m³ of walls, 82 m³ of beams, 47 m³ of columns
≈ 120 tof HA FE500 steel — 28.7 t in the substructure, 91.5 t in the superstructure
1,340 m²of two-layer waterproofing, 432 m of upstands, 160 m² of wet rooms
≈ 1,800 m²of insulated double partitions, imposed by the acoustics
6,854 m²of renders, inside and out
3,376 m²of stripping, 826 m³ of excavation, 872 m³ of backfill

What the documents require

Concrete B10 to B30, waterproofed in the substructure, "highly detrimental" cracking class below ground; batching plant mandatory; steel and formwork inspected before every pour; compaction checked by an approved laboratory.
Fair-faced concrete, sample approved by the architect on pain of redoing the work.
SBS bitumen waterproofing under technical approval, flood tests of 72 then 24 hours, specific ten-year cover; spray insulation prohibited.
Acoustics: façades above 35 dB on the runway side, internal insulation of 50 to 55 dB, double masonry partitions throughout, floating screed everywhere — 56 mm more on every raw floor —, flatness of 7 mm under a two-metre rule.
Fire safety: high-risk rooms fire-rated one hour, shafts half an hour; no smoke extraction to reserve.

The interfaces where failures are born

Structure ↔ waterproofing: parapet level, screed fall, upstands above the protection, drainage reservations — decided before the parapets are poured, not after.
Screed ↔ floors: the acoustic report sets the slab levels; substrate moisture is measured before laying, the calendar is not enough.
Structure ↔ services: shafts sealed before ducts, anti-vibration bases under roof equipment, an existing 600 mm collector to protect at the edge of the site.

What the site imposes

Restricted area under access control: staff vetting within ten days, badges, imposed routes, permanent guarding, no accommodation on site, a single access.
Safety stoppages imposed by the operator: they trigger amendments — a schedule lever to write into the programme, not a risk to endure.
Sensitive networks not mapped under the footprint: to obtain before any excavation; co-activity with no claim possible, coordination borne by the package.

What the contract commits

Seven months at a firm, non-revisable price: the material exposure on 120 tonnes of steel is priced and covered, not endured.
Daily penalties with two contradictory caps between documents, and an ambiguous lump-sum clause — to be clarified before submission, otherwise provisioned at worst case.
3% performance bond, 10% retention per instalment, payment at 60 or 90 days depending on the document, joint-costs account kept by the package: the financing cost goes into overheads, with its date.

Reference presented without client, owner or site name, out of respect for confidentiality and GDPR. The quantities quoted are those of the tender file's bill of quantities; no bid amount is published.

Holding the contract once it is signed

Milestones, variances, changes and accountabilities on one timeline. The screen reads on two levels: the decision it serves, and the method behind it.

ADVISORY · DELIVER

The contract becomes a decision system.

Milestones, variances, changes and accountabilities on one timeline.

What is not qualified early gets negotiated late, under pressure.

CONTROLLED · DECISION DUE · DRIFT · ALERT

Method

Versioned baseline, RAID log, change control and decision log.

Contract milestone / current forecast
Risk · action · owner · due date
Notice period: a well-founded but late claim is lost
Change request / impact / decision
Estimate to complete and estimate at completion
Acceptance evidence and caveat

Every forecast is dated and states its assumption. You know exactly what it commits to.

Real study assignments, told without the names

A bid desk run for three years, a fourteen-package all-trades file, quantities recomputed from the drawings: what we did, what it produced, and what was hard. Client, site and town names are removed; the volumes of work remain.

TRACK RECORD · REAL ASSIGNMENTS, NAMES WITHHELD

01
A finishing-trades contractor, around ten staff, northern France. No in-house estimating department.
When · Three consecutive years, between 2017 and 2021.
What we did
We ran its entire bid desk, exclusively: spotting the consultations, inventorying the documents, quantity take-off, unit-price build-up, technical submission, form of tender, filing. It had no estimating department — we were it.
What it produced
111 priced bills of quantities, 68 specifications and tender regulations analysed, 54 signed forms of tender, 48 execution programmes, 47 technical submissions, 27 drawing sets. Up to a hundred consultations handled in a single month.
What was hard
The pace. At a hundred files in a month, what breaks is never the pricing: it is the reading. We held it by industrialising the document inventory and the hunt for contradictions between documents — so that engineering time went to the line items carrying most of the money, and nowhere else.
02
A local healthcare facility, new build, all-trades tender file.
When · File from the 2017-2021 period, analysed in 2026.
What we did
We went through the entire tender file — fourteen packages, from external works and services to signage, taking in structure, waterproofing, joinery, cladding, heating and ventilation, electrical works and lifts — to draw out a usable schedule of works, then costed it blind, line by line.
What it produced
1,063 all-trades line items named and classified by package and family of works. 75 % of them covered by a median price drawn from our own bills. The remaining 25 % are listed as gaps, package by package — that is the part of the document we show first.
What was hard
The file's bills were blank: no prices, no quantities, forty-four priced lines out of one thousand and sixty-three. The take-off was left to the bidders — meaning the client handed every contractor the act that determines the price, with nobody checking that they were all measuring the same thing.
03
Five competing contractors, one and the same package, one and the same tender file. Measured from our own archive.
When · Bids from the 2017-2021 period, measured in 2026.
What we did
We took the five bids submitted on the same works and traced back, for each one, not the price shown but the quantity it had measured before setting it.
What it produced
From 281 to 505 square metres measured for the same works, and from 9.73 to 25 euros per square metre: a one-to-four-point-six spread on a single line of the bill. The full comparison, quantity by quantity.
What was hard
Proving the gap came from the take-off, not the price. A bill of quantities does not say so: it shows an amount that looks firm. We had to rebuild each bidder's quantity to show that five serious contractors had simply not been pricing the same building.
04
Our in-house price reference, built for the contractors we advise. A multi-package public maintenance framework agreement.
When · 2018 contract, analysed in 2026.
What we did
We opened the schedules of rates actually accepted on a maintenance framework agreement — nine packages, nine successful contractors, from masonry to electrical works — then cross-checked them, family of works by family of works, against our own submitted prices.
What it produced
4,905 lines read, 1,406 awarded prices retained, fourteen comparable families of works, and a table that answers one question only: where are we above the winning price, and by how much.
What was hard
The two sets do not carry the same level of proof, and that is written at the top of the document. Our lines self-verify at 42 % against their own total — quantity times unit rate equals the line amount. A schedule of rates never does: it carries no quantities. We also discarded four families out of fourteen whose gap was implausible, rather than publish a table that held together nicely.
05
The technical submissions actually filed by a finishing-trades contractor, across three years of consultations.
When · Documents from 2017-2021, re-read in 2026.
What we did
We opened and read them one by one, to measure what they actually contained — not what a template claims they ought to contain.
What it produced
31 submissions opened and read, none illegible. A drafting frame in thirteen sections, ranked by actual frequency: staffing, plant, programme, safety, comparable project references and product data sheets appear in twenty-nine out of thirty-one. Twelve drafting rules come out of it, each drawn from a document we opened.
What was hard
The first count announced forty-seven. Only thirty-one really were: the rest were duplicates and files whose name carried the word without the content. We wrote the discrepancy down rather than keep quiet about it — an announced figure you correct beats an announced figure you defend.
06
A bidder for a structural works and waterproofing package, inside the restricted area of an international airport. Moroccan contract, firm non-revisable price.
When · 2026.
What we did
We ran the file end to end: seventeen documents read, take-off from the dimensioned drawings, a day-by-day seven-month execution programme, a technical submission in two volumes, a site layout for a landlocked footprint, a security-constraints note — then the written questions to the client, before pricing.
What it produced
Seventeen documents read and each tied to what it evidences; about 1,200 square metres of net floor area, four quadrants around a circular patio; close to 800 cubic metres of structural concrete and 120 tonnes of steel held by the bill; 1,340 square metres of waterproofing and 432 metres of upstands; nine questions asked before the first price.
What was hard
The file arrived as an eighteen-month, three-site, all-trades parent contract, inside which the real package had to be isolated: one site, seven months. Reading both contractual tiers avoided scheduling — and paying for — a site installation two and a half times too long. And a floating screed imposed by the acoustic report added fifty-six millimetres to every raw floor: it is written in no structural document.
07
A roof-slab floor, top reinforcement drawing, structural sub-package.
When · 2026.
What we did
We calibrated the drawing before measuring anything: seven bays checked one after another against their written dimensions, horizontally and vertically, then the scale set on the longest reliable span. Areas and deductions came afterwards.
What it produced
A drawing of 48,346 vector segments, 10,727 of them dimension lines; seven bays giving the same scale to within five hundredths in both directions; the title block confirming the value found, independently of our own measurement; an annotated drawing delivered with the quantities, the measurement convention applied and the list of assumptions.
What was hard
A scale stated in the title block is not believed, it is verified. A drawing reprinted at the wrong size gives a correct title block and wrong lengths, with nothing to flag it. We measure the grid first, and we never hand over a quantity without listing the items we did not verify: a take-off with no list of assumptions is an opinion.
08
Contractors exposed to price adjustment, in France and Morocco.
When · Reference corpus maintained through 2026.
What we did
We sorted the price-adjustment indices by nature of works and by country, with what each one actually measures — so that a price is adjusted by the index matching its content, not by the one carrying the sector's name.
What it produced
Eighty-four French indices sorted and documented; the official Moroccan indices for building, civil engineering structures and road works; the adjustment formula and its components; and for each one, what it weighs — the all-trades building index is close to 59 % a labour index, so it under-adjusts a package heavy in materials.
What was hard
A building index applied to a civil engineering structure gives a wrong result, and the error can change direction depending on the period: we measured months where civil works rose two to three times faster than building, then fell harder afterwards. An index still marked provisional is flagged as such — it will be revised, and it will recompute everything built on it.
09
All-trades projects, private and public clients alike.
When · Method tested on files from 2017 to 2026.
What we did
We write every seam between two packages as a dated deliverable — who does what, hands over what to whom, under whose check — into the upstream package's specification, and we make it a chapter of the technical submission.
What it produced
A grid of ten interfaces, each with its control point and its reference defect: finished level and upstands between structure and waterproofing, builder's work openings signed off before the pour, fire-stopping attributed to a named party, screed moisture measured before the floor finishes, base tolerances written into the mason's package at the value the carpenter requires.
What was hard
Two contractors can each comply with their own standard and the works still be rejected between them. Five millimetres of flatness defect at the foot become a centimetre out of plumb at the head. And on the industry's most frequent dispute — laying a floor finish on a screed that is still damp — two standards disagree: one reasons in elapsed time, the other in measured moisture. A waiting period met is not a dry substrate.

No client name is published, with or without their consent. We publish no win rate: it is not measured, and an unmeasured figure is not a reference.

What we do

Design and technical studies, from first sketch to construction documents.
Quantity surveying and construction economics: quantities recalculated from dimensioned drawings, prices per line item, compared options.
Owner's advisory: brief, specifications, analysis of contractor bids.
Delivery oversight: critical path, variance, snagging, sign-off at handover.
Second opinion on a file already prepared, before commitment.
Interface coordination between trades — slab level and waterproofing upstands, screed dryness before floor finishes, openings cast before the pour: this is where defects are born, and almost nobody writes it down.
Independent re-measurement of a bill already priced: we re-measure the items carrying most of the money, we write down the measurement convention applied, and we list what we did not verify.
Written requests for clarification to the client — what the file leaves out becomes a question, never an assumption quietly filled in.

What we deliver

Programme brief & specifications

Design package (drawings, notes, phasing)

Detailed quantities & cost estimate

Requests-for-clarification note, ranked by impact

Comparative analysis of contractor bids

Project programme & critical path

Progress reports & handover records

The method

Survey

We measure what exists and what constrains it before drawing anything.

Design

One technical solution, its variants, and what each one truly costs.

Cost

We rank line items by amount: the first twenty carry most of the contract, and those are the ones we recalculate from the dimensioned drawings. A price that cannot be explained will not hold.

Oversee

Delivery is steered on variance — time, quantity, quality — and every change creates a version, never a rewrite.

WHAT YOU WILL HAVE IN HAND · The Living Execution File

Touch one requirement: affected design, economics, schedule and evidence identify themselves immediately.

Touch one node: what it drives lights up.

We turn a project intention into a system that can actually be decided, procured and followed through. The point is not to add documents: it is to hold the project brief, technical choices, economics, ownership and schedule in one evidence line.

At first glance, an executive sees what is ready, what depends on a decision and what would prevent delivery. Every decision opens its origin and consequences; no warning remains an unexplained colour.

Open the technical file

Requirement → solution → cost → time → evidence

The specialist register displays the requirement graph, dependencies, sizing assumptions, interfaces and owner of every decision. A change does not rewrite history: it creates a version, marks affected objects and requests renewed validation.

Economic values, quantities and dates display only when source and scope are present. Missing file information remains N.F. and opens the evidence request. Comparison mode shows two project versions without merging them.

Project brief, DIAG (site diagnostics) and feasibility: existing conditions, operating constraints and further investigations before any design begins.

ESQ, APS, APD (sketch, preliminary and detailed design stages): variants, construction principles, provisional then trade-by-trade fixed cost estimates.

PRO and DCE (detailed design and tender file): drawings, sections, quantity take-off, CCTP specifications, a DPGF or DQE bill of quantities (BoQ) or a BPU schedule of rates depending on the contract form, schedule and bid-analysis criteria.

ACT (tender clarification): questions and answers, technical and financial analysis of bids, adjustments before award.

EXE, SYN, VISA (execution, coordination and sign-off): shop drawings, interfaces between work packages and verification of design submissions against the approved project.

Quantity take-off and cost plan: the works → zone → package → line item → unit → quantity → unit price → amount chain, each line carrying its status — measured, confirmed, provisional or N.F.

OPC (schedule coordination): elementary tasks, FS/SS/FF links, free float, total float and critical path.

Change control: variation order, cause, cost/schedule impact, decision, revised baseline and traceability.

DET, OPR, AOR, GPA, DOE, DIUO (construction supervision through handover): site instructions and final account, snagging list and sign-off at completion, defects-liability guarantee, as-built drawings and operating data.

The execution file organises and circulates the information supplied to the project; it does not generate quantities unless a usable BIM feed is provided, and replaces neither the design team’s technical judgement nor contractual decision authority.

THE QUESTIONS THAT SET THE PRICE

What we will ask you before we start.

Four questions we ask on every file in this domain. Each comes from an incident someone paid for — us, or a client before us.

Who owns the interfaces between packages — and where is it written?

A building rarely fails in the middle of a package: it fails at the seam between two. Finished level and chase between structure and waterproofing, builder's work openings signed off before the pour, fire-stopping attributed to a named party, screed dryness measured before the finishes. We write each interface as a dated deliverable — who does what, hands over what to whom, under whose check — into the upstream package's specification, and we make it a chapter of the technical submission.

If nobody asks it — Nobody seals the shafts, and the tiler lays on a screed that is still damp: the industry's number-one dispute, settled by an elapsed waiting time that is not dryness.

Is the take-off yours, or the client's?

On the same package and the same file, five competitors measured 281 to 505 m² and priced 9.73 to 25 euros per square metre — a 1-to-4.6 spread on a single line (internal record, file handled between 2017 and 2021). The take-off makes the price, not the other way round. We re-measure from dimensioned drawings the items that carry most of the amount, we write down the measurement convention applied and the assumptions taken, and we list what we did not verify.

If nobody asks it — A firm price is signed on someone else's quantities, and the gap surfaces at the final account — when it is no longer negotiable.

Which tolerances of the next package must appear in the previous one?

A mason can deliver a base compliant with his own standard and have it refused by the timber-frame carpenter, whose base tolerances are stricter: five millimetres of flatness defect at the foot become a centimetre out of plumb at the head. We write the downstream tolerance into the upstream specification, at its value, and we put the joint acceptance of the base on the programme — with a date, not an intention.

If nobody asks it — Two contractors each compliant with their own standard, a structure refused between them, and an arbitration the client pays for alone.

What does the file say that nobody has read — and what does it leave out?

We inventory every document, technical reports included, then we look for the contradictions between them: that is where the costs hide. An acoustic requirement or a ceiling height can force a tighter stud spacing than the one that was priced — moving from 0.60 m to 0.40 m changes the quantity of framing per square metre, and no architect's drawing says so. What the file leaves out becomes a written question to the client, never an assumption filled in quietly.

If nobody asks it — An accurate price, calculated for a building that is not the one in the file.

CAPABILITY SCENARIO — NOT A CLIENT REFERENCE

When we get the call

A client inherits an incomplete design package and an estimate that no longer stands up. We take the line items carrying most of the money, recalculate them from the dimensioned drawings with every assumption written down, and hand back an estimate that can be defended in front of contractors. The project restarts with a figure open to line-by-line scrutiny.

Related disciplines

A file rarely draws on a single discipline.

Consulting & Management

Structured decision

Finance & Management

Defensible economics

All disciplines in this practice

Planning something in Engineering & Construction?

Write to us. We respond with an assessment, not a brochure.

Write to us