Best for: Small, straightforward works directly between a homeowner and a builder — a bathroom refurbishment, a small extension, a garage conversion. Projects where there's no architect or professional team involved.

How it works: A simplified contract designed specifically for domestic clients who are dealing directly with a builder without a contract administrator in the middle. It sets out the scope, price, and programme in plain language, and provides a basic process for handling changes and disputes.

What it doesn't do: It's not designed for complex projects. There's no provision for a full professional team, no detailed variation mechanism, and no real cost control framework. For anything above modest scale or complexity, you'll quickly outgrow it.

Warvena's view: We don't use this form on our projects. By the time a client is commissioning Warvena, they typically have an architect involved and a professional team in place. The Home Owner contract isn't the right fit for that context.

Best for: Smaller, well-defined projects — typically under £250,000 — where the design is complete, the scope is clear, and an architect or contract administrator is in place.

How it works: A streamlined form with a straightforward payment and variation mechanism. The architect acts as contract administrator, issuing instructions and certifying payments. There's less administrative weight than the Standard Building Contract, which makes it appropriate for simpler projects where full JCT machinery would be disproportionate.

What it doesn't do: Doesn't suit projects with significant complexity, a large number of specialist subcontractors, or a scope that's likely to evolve. The variation provisions are lighter than in the Standard form, which can create friction if changes are frequent.

Warvena's view: Appropriate for smaller renovation and refurbishment projects where the scope is genuinely well-defined. For bespoke new builds or complex renovations, the Standard Building Contract gives both parties better protection.

Best for: Mid-complexity residential projects — typically £250,000 to £1 million — where there's a full professional team, the design is reasonably complete, and the architect acts as contract administrator.

How it works: A middle ground between Minor Works and the full Standard Building Contract. It has more detailed provisions for variations, extensions of time, and payment than Minor Works, but without the full administrative weight of the Standard form. Works well where there's a named subcontractor or two but the project isn't sufficiently complex to justify the Standard form.

What it doesn't do: Doesn't suit projects with a large volume of specialist subcontractors, complex design elements, or significant performance specification requirements. For a high-specification Passive House build or a large bespoke coastal home, you'll want the Standard form.

Warvena's view: A solid form for mid-range renovation and refurbishment work. On new builds, we generally move to the Standard Building Contract — the additional provisions justify themselves on projects of any real complexity.

Best for: Full bespoke new builds and complex renovations with a complete professional team — architect, structural engineer, M&E consultant — where the design is at RIBA Stage 4 and the scope is well defined.

How it works: The most comprehensive form in the JCT suite for private residential work. It comes in three variants — with quantities (SBC/Q), with approximate quantities (SBC/AQ), and without quantities (SBC/XQ). The architect acts as contract administrator, certifying payments, issuing instructions, and managing the formal variation process. There are detailed provisions for extensions of time, loss and expense, defects liability, and dispute resolution.

What it does especially well: It's the right form when the drawings are complete and the scope is fully defined. The variation mechanism is robust, the payment provisions are clear, and the contract administrator role gives the architect formal authority to protect the design intent throughout construction.

What it doesn't do: It's not designed for projects where the scope is uncertain at the outset. If significant elements are left as provisional sums or the specification is still evolving, the Standard form creates friction rather than removing it.

Warvena's view: This is the form we use on most bespoke Warvena new builds. Our pre-construction and PCSA phase is designed to get projects to the point where the Standard Building Contract works as intended — with complete drawings, a resolved specification, and a scope the contractor can genuinely price.

Best for: Projects where the client wants a single point of responsibility for both design and construction — the contractor develops and delivers the design, and the client has one relationship to manage.

How it works: The contractor takes on design responsibility as well as build responsibility. The client provides an Employer's Requirements document setting out what they want; the contractor responds with a Contractor's Proposals. Design risk sits with the contractor.

What it does well: Simplicity. One contract, one relationship, clear accountability for the finished product. It can also produce faster programmes — design and construction can overlap — and tighter cost certainty, because the contractor controls both sides of the equation.

What it doesn't do: It doesn't suit clients who want design independence. When the contractor holds design responsibility, design decisions are inevitably influenced by buildability and margin. The architect on a design and build project works for the contractor, not the client. That's a fundamental shift in whose interests the design serves.

Warvena's view: We don't typically work on design and build projects for bespoke residential clients. Our clients come to us with an architect they've chosen and a design they've invested in. The traditional contract model — where the architect's loyalty is entirely to the client — is the right structure for that relationship. Design and build suits volume developers and clients who want simplicity over design quality.

Best for: Projects where the scope isn't fully defined at the outset — renovations of existing buildings with unknown structural condition, sites where the ground hasn't been fully investigated, or bespoke new builds where fit-out decisions haven't been finalised.

How it works: The client pays the contractor's actual costs — labour, materials, plant, subcontractors — plus an agreed management fee. Full open-book accounting. Every invoice is shared. The contractor's profit is the fee, not a margin built into a lump sum.

What it does well: Transparency. And flexibility. Cost plus means you pay what things actually cost, not what a contractor estimated they might cost plus a risk premium. It accommodates design evolution during the build without the friction of formal variation orders. And it removes the adversarial dynamic that a fixed-price contract can create when things change — because on a bespoke build, things always change.

What it doesn't do: Provide certainty over the final figure. And it requires a contractor you trust completely — open-book only works if the books are genuinely open.

Warvena's view: On most bespoke Cornwall new builds, the JCT Prime Cost contract is our preferred structure. It suits the way these projects actually unfold — with decisions evolving as the building takes shape, fit-out choices being made when the space is real rather than drawn, and a relationship built on transparency rather than a lump sum that both sides spend the project trying to protect. For clients who require a fixed price for finance purposes, we use our PCSA phase to get the design complete enough that a Standard Building Contract is genuinely reliable.

JCT Home Owner Contract Project type: Small domestic works · Design responsibility: Builder or client · Scope certainty needed: High · Warvena use: No

JCT Minor Works Project type: Simple, small scale · Design responsibility: Architect · Scope certainty needed: High · Warvena use: Occasionally

JCT Intermediate Project type: Mid-complexity · Design responsibility: Architect · Scope certainty needed: Medium-high · Warvena use: Renovation projects

JCT Standard Building Contract Project type: Full bespoke new build · Design responsibility: Architect · Scope certainty needed: High · Warvena use: Most new builds

JCT Design and Build Project type: Single-point delivery · Design responsibility: Contractor · Scope certainty needed: Medium · Warvena use: No

JCT Prime Cost Project type: Uncertain scope / open-book · Design responsibility: Architect · Scope certainty needed: Low-medium · Warvena use: Preferred for new builds

It depends on the project — but our honest position is this:

For bespoke new builds in Cornwall, we default to the JCT Prime Cost contract where the client is open to it. It's a more honest structure for the way these projects unfold, and it produces better outcomes when fit-out decisions are made at the right moment rather than forced too early.

Where a fixed price is required — for mortgage or development finance — we use the JCT Standard Building Contract, and we invest seriously in the pre-construction phase to make sure the scope it describes is genuinely complete.

What we don't do is recommend a contract form because it's convenient. The contract should fit the project. If you're not sure which form is right for yours, that's a good conversation to have before the design is finished — not after.

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