South London builders for extensions, refurbishments and loft conversions
Established & Trusted
High-Quality Work
Fair Pricing
Clear Communication
HOUSE EXTENSIONS

Built to drawings and spec, with the detail handled properly

If you are working with an architect, you need a builder who respects the design intent and understands the sequencing behind it. We deliver architect-led extensions across South London, with clean setting out, proper structural work, and finishes that line up with the details. You get clear costs, realistic programming, tidy site standards, and consistent oversight from start to finish.

01689 610425
HOW WE WORK

Buildability first, tidy delivery, clear reporting

We are used to working from architectural drawings, engineering, and written specifications. We flag issues early, confirm details before they become site problems, and keep communication straightforward between client, architect and building control.

Architect-led house extension build in South London

A builder who can actually deliver the design

Architect-led work lives and dies on the details. Levels, junctions, openings, steels, rooflines, drainage and the finish all need proper control. We take setting out seriously, keep variations transparent, and follow the spec so the end result matches what was designed.

If drawings are still being finalised, we can help with buildability feedback, sequencing, and practical options that protect the intent while keeping the job realistic on cost and programme.

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What you get with Building Plus

Design-aware building, tidy delivery, and the sort of communication architects expect. We focus on the work that makes an extension feel right: structure, setting out, junctions, and finishing.

Buildability support
Buildability support
Practical input on sequencing, details and site constraints before work starts.
Built to drawings
Built to drawings
Accurate setting out, proper structural work, and delivery aligned to the spec.
Detail and finish
Detail and finish
Clean junctions, good levels and finishes that look correct in the final space.
Clear oversight
Clear oversight
Tidy site standards, clear updates, and issues handled properly as they arise.

Frequently asked questions

Do you regularly work with architects and structural engineers?
Yes. We are used to working from architectural drawings, structural calculations and written specifications. We also raise RFIs and confirm details early so the build runs cleanly.
Can you help with buildability before we go to site?
Yes. We can review access, sequencing, temporary works, steels, drainage runs and key junctions, and highlight anything likely to affect cost, programme or build quality.
How do you handle changes and variations?
Any change is discussed first, priced clearly, and agreed in writing before we proceed. That keeps budgets controlled and avoids disputes later.
How do you keep the design intent on track during the build?
We focus on setting out, levels and junctions, and we confirm details before closing up. If something clashes on site, we flag it early and agree the best resolution with you and your architect.
Do you provide programme updates and site reporting?
Yes. We keep you updated on progress, upcoming decisions and any risks to programme. If you have an architect acting as contract administrator, we are happy to feed into that process.
Can I live in the house during the build?
In many cases, yes. We plan the work to reduce disruption, protect existing areas, and keep the site tidy so the house stays usable wherever possible.
Do you use subcontractors?
We keep a consistent main team and stay hands-on. Where specialist trades are needed, we tell you upfront and manage them properly.
Do you help with planning permission and building control?
Yes. We regularly work alongside architects and building control. If planning approval is needed, we can help you understand what is required and how it affects the build programme.
Are you fully insured?
Yes. We carry full public liability and employer's liability insurance, so your home and everyone on site is properly covered.

Start your project with us

Arrange an initial chat to talk through your plans and next steps.