One contract for design and construction

In the traditional model you sign twice: once with the designers, once with the builder. Every gap between those two contracts is a gap you pay for. WALLNUT signs once. The team that draws it builds it, and the person who set the budget is the person who owns it.

What the independent research says

These are not our numbers. They come from Revisiting Project Delivery Performance, by Keith Molenaar (University of Colorado Boulder) and Bryan Franz (University of Florida) for the Construction Industry Institute and the Charles Pankow Foundation — 212 projects completed between 2008 and 2013, of which 80 design-build and 53 design-bid-build.

Compared with design-bid-build, design-build projects showed 3.8% less cost growth, 1.7% less schedule growth, and delivery from design to completion 102% faster — 36% faster in the construction phase alone.

Two honest caveats. The sample is North American, public and private, and predates current cost inflation. And it measures the method, not this firm: it tells you what integrating design and construction tends to do, not what we will do on your project. Read the summary.

Where the money actually goes

Cost growth in a split contract rarely comes from materials. It comes from the seam. A detail the drawings left open becomes a variation order. A structural clash found on site becomes three weeks of nobody being responsible. A specification the builder prices differently from how the architect meant it becomes a negotiation you are in the middle of.

With one contract those are internal problems, resolved before they reach you, by people whose margin depends on resolving them early. That is the whole mechanism. Everything else — BIM, reality capture, the dashboards — exists to find the seams sooner.

The objection you should raise

“If the same firm designs and builds, who protects me from them?” It is the right question, and the honest answer is: not the contract structure. What protects you is what you can verify.

So we make three things verifiable. Quantities are open: you see the measured bill, not a lump sum with a margin hidden inside it. Design decisions are recorded against the model, so a change has an author, a date and a cost. Immersive review before construction, so you approve what will actually be built rather than a drawing you are asked to trust.

And if you want a second pair of eyes, hire one. An owner’s representative reviewing our measurements is a cost we would rather you spend than a doubt you carry.

Comparing bids when only one firm bids the whole thing

The second real objection: a split tender lets you compare five builders on the same drawings. An integrated contract does not.

What you can compare is the part that decides the outcome: the measured quantities, the scope explicitly excluded, the assumptions behind the contingency, and the named people who will run it. Ask for those from anyone you are considering, us included. A proposal that will not show you its exclusions is not cheaper — it is less finished.

Who this suits, and who it does not

It suits owners who want one accountable party and a single decision path: companies fitting out or building their own premises, and private owners building or restoring at scale who do not intend to referee between consultants.

It suits less an owner who wants a specific architect they have already chosen, or a project where the design is complete and only execution remains. We will say so in the first conversation rather than take the work and fit it badly.

Design-led: selected work

Every project begins as a design problem, not a construction quote: restraint and material honesty over decoration, resolved in full BIM and built by the same studio that designs it, so the design reaches handover intact. Selected work includes Hotel Umay, an 11,000 m² wellness hotel on the Melides coast, Villa Ninho d’Águia in Albufeira (2,000 m²) and the Casa do Paço quinta restoration in the Douro (650 m²).