We design, plan and build house extensions across Mortlake and the wider Richmond upon Thames borough — one team, one fixed price, one project manager from sketch to handover.
Typical scope +18 to +60m²
Cost guide From £2,500 / m²
Build time 12–22 weeks
Consult Free 1–2 hour visit
BUILDING IN MORTLAKE
Victorian terraces between Barnes and Kew respond well to side-return kitchens and rear dormers — we design and build both across SW14, where our portfolio already includes eight completed East Sheen projects a few streets away. Fixed price, planning handled.
Side-return and rear extensions turn Mortlake's narrow Victorian kitchens into open-plan family rooms. We design and build them in-house, handling planning where needed.
Local advantage
Why homeowners in Mortlake choose Dali Pro Services for house extensions
01 · PLANNING HANDLED
Permitted development or full planning — we tell you which on the first visit.
Many single-storey rear and side-return extensions in Mortlake fall under permitted development; double-storey and wrap-around schemes usually need a full application to Richmond upon Thames Council. Much of the area sits within conservation areas, where materials and rooflines are tightly controlled — we design to the register from day one. Our own team prepares the drawings and submits the application — one point of contact owns both the approvals and the build.
02 · ONE TEAM
Steels, thresholds and the kitchen — one team owns every junction.
An extension lives or dies where old meets new: the steel opening, the level threshold to the garden, the drainage runs, the kitchen that anchors the space. Our architects, structural engineers and site team sit in the same office, so nothing is lost between a designer’s drawing and a builder’s interpretation.
03 · TRANSPARENT PRICING
From £2,500 / m² — itemised and fixed.
Your quotation is broken down line by line — groundworks, shell, glazing, fit-out — and fixed against the agreed drawings. You pay in stages, only after each stage is signed off; variations only happen when scope genuinely changes, through written authorisation.
Yes — Mortlake (SW14) is well within our Richmond upon Thames working area. We deliver several house extension projects across this borough each year.
How long does a house extension project take in Mortlake?
On site, the build phase is typically 12–22 weeks. Add time up front for design, planning approval and structural sign-off — we give you a firm end-to-end programme with the fixed quote after the free site visit.
What does a house extension cost in Mortlake?
Typical range: From £2,500 / m². Our online calculator gives you a tighter figure based on your house type and ambitions; the fixed quote follows a free site visit.
Will I need planning permission in Mortlake?
It depends on the property. Many house extensions fall under permitted development; where a full application to Richmond upon Thames Council is needed (conservation areas, listed properties, larger schemes), we prepare and submit it end-to-end.
How long does a typical extension take?
A single-storey extension takes 12–16 weeks from breaking ground to completion. Double-storey runs 16–22 weeks.
Can we live in the house during the build?
For most rear extensions, yes. We dust-seal the working area and maintain access to your kitchen and bathroom.
How much does an extension cost?
In London, expect £2,500–£4,000 per square metre for a finished extension including kitchen and finishes. Use our calculator for a free estimate.
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