When a bespoke contract beats a standard build contract
Spring & Co, Stockport. Construction & property consultants since 1992
A custom-drafted contract earns its cost when a project carries risk the standard forms were never written to hold: an unknown existing structure, a phased handover, a funder with its own drawdown conditions, a listed building. For a clean new build with a settled scope, a standard JCT or NEC form, lightly amended, is cheaper, faster and just as safe.
We see the same thing most weeks. A developer forwards a contract the contractor's own solicitor has drafted, asks whether it is fine to sign, and underneath the friendly wording every risk has quietly moved onto them. That is the version of a custom contract that costs you money. The one we recommend does the opposite.
What people mean by a "standard build contract"
In the UK that almost always means a JCT or an NEC form. The JCT suite covers most private work: JCT Design and Build 2024 when the contractor carries the design, the JCT Standard Building Contract for larger traditional projects, and JCT Intermediate or JCT Minor Works for smaller jobs. Public and infrastructure work leans on NEC4, whose Engineering and Construction Contract runs from Option A, a fixed lump sum against an activity schedule, through Option C, a target cost with the pain and gain shared, to Option E, fully cost reimbursable. International schemes use FIDIC.
These forms are not generic. They are negotiated between the industry bodies, updated every few years, and argued over in court for decades, so when a dispute lands everyone in the room already knows what clause 2.28 does about an extension of time. That shared understanding is worth real money. It is the main reason we reach for a standard form first and only leave it when the project makes us.
What a custom contract is, and what it costs to draft
A custom contract, what the trade still calls a bespoke contract, is written from scratch for a single project rather than adopted from a published form. There is a middle option most people miss. You keep the standard form and bolt on a schedule of amendments, which JCT users do as a matter of course and NEC users handle through Z clauses.
The cost difference is almost all in the drafting. A standard JCT form off JCT On Demand is a couple of hundred pounds, roughly £100 to £250 for a single-project download. A solid schedule of amendments from a construction solicitor runs about £2,000 to £8,000. A fully drafted custom contract starts near £5,000 and climbs past £25,000 once you add the design responsibility matrix, the collateral warranties and the funder's requirements. And that is before anyone on your side reads it properly.
| Route | What it is | Cost to produce | Best for |
|---|---|---|---|
| Standard form | Published JCT or NEC contract, used as written | £100 to £250 | Clean new build, settled design, ordinary risk |
| Amended standard | Standard form plus a schedule of amendments or Z clauses | £2,000 to £8,000 | Most schemes that need a few project-specific changes |
| Custom contract | Drafted from scratch for one project | £5,000 to £25,000 and up | Unusual risk, complex funding, higher-risk buildings |
If you want a second pair of eyes on a route before you commit the budget, our construction project management team weighs this up for clients most weeks, well before a contract is signed.
When a custom contract actually beats a standard form
Reach for a custom or heavily amended contract when the risk does not fit the box the standard form draws. Four situations come up again and again.
When you cannot see what you are buying. On a refurbishment or a conversion you are pricing work behind walls and under floors that nobody has properly opened. A lump-sum standard form turns every surprise into a variation and an argument. A target cost route such as NEC Option C shares the surprise instead, rather than pricing it as a fat contingency you pay whether or not the risk ever shows up.
When the money has conditions. A development finance agreement will impose step-in rights, drawdown milestones and its own definition of practical completion. Those have to be threaded through the building contract, and a plain JCT form does not do it on its own. This is where our fund monitoring work and the contract have to line up exactly.
When the project is a higher-risk building. Under the Building Safety Act 2022, a residential building of 18 metres or 7 storeys and above sits in the higher-risk regime, with dutyholder roles, the golden thread of information and gateway approvals from the Building Safety Regulator. Those duties belong in the contract, not in a side letter you forget about.
When the phasing is awkward. Partial possession, sectional completion, a live building kept trading around the works: all of it needs the completion, insurance and liability machinery reworked so the two parties are not reading the same clause two different ways.
When the standard form is the right call
Here is the part some consultants will not say out loud. For most schemes under about £2m, on a clean site with a settled design, a fully custom contract is money wasted. An amended custom contracting arrangement built on a JCT Design and Build base gives you the protection you actually need, and because that base has been tested in court you are standing on firmer ground than any clever clause a solicitor wrote last week.
The honest downside of going custom is that it is slow. A properly drafted contract adds three to six weeks before a spade goes in, and I have watched that delay swallow the risk premium it was meant to protect on a site that turned out clean. If your programme is tight and your risks are ordinary, that trade rarely pays.
There is one custom contract you should never sign without advice. The contractor's own.
When a builder hands you their in-house form, assume it has been written to protect them, because it has. Have it reviewed before it goes anywhere near a signature. That is the whole difference between a custom contract that works for you and one that quietly works against you, and it is a large part of what our construction management service is there to catch.
What this looks like around Stockport and Greater Manchester
Our patch shapes which route we recommend more than people expect. A lot of the work around Stockport and the wider Greater Manchester belt is old cotton and textile mills coming back as flats, studios and offices. You cannot fully survey what sits behind a 150-year-old brick wall or under a cast-iron floor until you open it up, so a lump-sum standard form on a mill conversion tends to become a run of costly variations. A target cost arrangement fits that reality better.
At the other end of the market, central Manchester's tall residential towers push a lot of local schemes straight into the Building Safety Act's higher-risk category, which reshapes the contract before anyone has argued about a single rate. And Stockport's town-centre regeneration has brought a wave of mixed-use schemes where a development agreement sits over the top of the building contract. Different problems, different paper.
Common questions
Is a custom contract always more expensive than a standard one?
Only to produce, not to live with. The extra cost is the drafting and the review, from around £5,000 upward against a couple of hundred pounds for a standard form. Once signed, a well written custom contract can be cheaper to administer because the risk sits where everyone agreed to put it. The waste is paying for that drafting on a project that never needed it.
Can I just amend a JCT form instead of going fully custom?
Usually yes, and it is what we suggest most often. A schedule of amendments keeps the tested standard form underneath and changes only the clauses your project needs, for roughly £2,000 to £8,000. You get most of the protection of a custom contract without throwing away the case law behind the base form.
Does the Building Safety Act force a custom contract?
No, but it forces changes. A higher-risk building of 18 metres or 7 storeys and above brings dutyholder duties and gateway approvals that have to appear in the contract, whether you get there by amending a standard form or drafting a new one from scratch.
Not sure which side of the line you are on?
If you are looking at a contract and cannot tell whether it protects you or the other party, that is exactly the call to make before you sign, not after. We read these for developers, funders and architects across the North West, and we will tell you plainly when a standard form is all you need. Talk to Spring & Co and send us the draft.