Design and build
Design and build contractors for London homes
If you would rather deal with one company from the first sketch to the last coat of paint, Alchemy Build offers a design and build route: our architect and designer partners develop the scheme, we price it as it develops so there are no surprises, and then our own team builds it under a single contract with a fixed programme.
What we do
One accountable team from brief to handover
Traditional procurement means appointing an architect, waiting for a design, tendering it to three builders and discovering the budget late. Design and build puts the builder in the room from the start, so the design is costed as it develops, buildability is sorted on paper rather than on site, and there is one company responsible for the result. It suits homeowners who want certainty and a single point of contact, and it works just as well when you already have an architect you want us to work alongside.
FMB
Federation of Master Builders member
Insured
Public and employers’ liability
W1
Based in Marylebone, working across prime central London
How design and build works
The four stages of a design and build project with us
01 — Consult
Brief, survey and budget
We visit, listen to what you want from the house, survey what is there and give you an honest budget range before any design work starts.
02 — Design
Concept to planning to construction drawings
Our architect and interior design partners develop the scheme with you, we handle planning, listed building consent and estate approvals where needed, and we cost every stage so the design and the budget stay together.
03 — Price
Fixed price and fixed programme
Once the drawings and specification are settled you get a detailed fixed price, a programme and a clear list of what is provisional, under a JCT contract.
04 — Build
Our own trades, a dedicated site manager
We build with our own carpenters, decorators and site team, a site manager on the project every day, and weekly reporting to you and the designer until handover and snagging are complete.
Already have an architect?
We are just as happy building your architect’s design
Design and build does not mean cutting your architect out. Many of our projects are architect-led: we join early to cost and advise on buildability, the architect stays in charge of the design, and we build it as drawn. Either way you get one contractor accountable for the finished house.
Selected work
Recent projects
Basement, Extensions & Mansard, Kensington
New basement, ground and first floor extensions and a rebuilt mansard roof on a conservation-area house in Kensington.
Grade II Listed Townhouse, Maida Vale
Whole-house refurbishment of a listed townhouse: restored fireplaces and panelling, new kitchen and bathrooms, and full redecoration.
Grade II Listed Rear Extension, Camden
A light-filled rear extension to a listed Camden home, detailed to sit quietly against the original house.
Questions
Common questions about design and build
Is design and build cheaper than the traditional route?
Not necessarily cheaper, but far more predictable. Because the builder is costing the design as it develops, you avoid the common problem of a finished design that is over budget and has to be redrawn.
Who owns the design?
You do. The architect’s drawings and the planning permission are yours whether or not you build with us.
What contract do you use?
A JCT contract appropriate to the size of the project, with a fixed price, a programme and clear provisions for anything that cannot be fixed until the building is opened up.
Can you take over a project that already has planning?
Yes. We regularly join at the construction drawing stage, or price a scheme that already has consent and then build it.
How we work
Consult, design, build: one accountable team throughout
01
Consult
We start with the house and the brief: a site visit, an honest conversation about budget and programme, and a clear view of what planning, listed building consent or party wall matters will be involved.
02
Design
Working with your architect and designer, or with ours, we develop a fully costed, buildable scheme and secure the approvals, so nothing is left to be discovered on site.
03
Build
A fixed programme, a dedicated site manager, our own trades and long-standing specialists, and a standard of finish that is checked room by room before we hand over.
“Alchemy Build delivered exactly what they promised — exceptional quality, clear communication, and absolute attention to detail.”
Homeowner, London
Start a conversation
Tell us about your project
Whether you have an idea and no drawings, or a full set of drawings ready to price, we are happy to meet, look at the house and talk through the best route to get it built.