What is early contractor involvement and when is it worth using?

A design completed without construction input is priced once and then, frequently, redesigned.

Early contractor involvement moves that conversation forward to the point where changing the drawing is still cheap.

What the contractor contributes during design

**Buildability,** meaning whether the detail can be built by the trades available, in the sequence proposed, at the quality specified.

**Programme,** which on a live site is the item that shapes the design most. A design that cannot be staged around an operating facility is a design that either costs more or takes longer.

**Staging and decanting,** including how the facility keeps operating, which connects directly to [decanting and temporary accommodation](/answers/decanting-and-temporary-accommodation-during-works).

**Cost, at the point it can still be influenced.** A cost plan during design identifies the elements driving the number while alternatives are still available.

**Access and logistics,** meaning whether plant can reach the work, where materials are stored, and how deliveries happen on a site with students or the public on it.

**Risk,** meaning which unknowns should be investigated now rather than discovered during construction, which is the [latent conditions](/answers/latent-conditions-and-unforeseen-site-issues) argument made early.

When it earns its place

**A constrained site,** where access decides the method.

**An occupied building,** where staging is half the design.

**A fixed window,** meaning a school holiday period or a shutdown, where the programme has to be proven before the design is finalised.

**A tight budget,** where a tender over the number means a redesign, and a redesign means the window is missed.

**Unusual or heritage fabric,** where the method affects the documentation.

When a conventional path is fine

A straightforward, well-documented scope on an unoccupied site with a normal programme does not need it. Competitive tender on complete documentation is efficient, and the cost advice a contractor would give would not change the design.

What it does not mean

It does not mean the price is settled before the design is. A cost plan during design is an estimate that tightens as the documentation develops.

It also does not remove the client's control of the design. The designer still designs and the client still decides. The contractor advises on what it will cost, how long it will take and whether it can be built the way it is drawn.

Where it develops into the contractor holding design as well, that is [design and construct](/answers/does-monument-environments-do-design-and-construct), which is a different arrangement with a different risk allocation.

What a client should expect from it

Specific advice, not general preferences. A staging plan. A programme with the constraint dates in it. A cost plan with the drivers identified. And a list of the investigations worth doing before the documentation is finished.