Rear extension
Create a wider kitchen-diner and open-plan living space across the back of your home.
Best for: Homes with usable rear garden depth.
Rear extensions in London
House Extensions in London
More space, more light and a ground floor that flows a home that simply works better, designed and built by one accountable London team.
- FMB Member
- 10-Year Structural Warranty
- Vetted & Work Inspected
- Fully Insured
- Dedicated Project Manager
- Weekly Updates
Isleworth, TW7
A side and double-storey rear extension, delivered end to end
This West London home was extended to the side and rear across two storeys, with the loft converted and the interior fully refurbished in the same programme.
Design, planning, structural work and construction were coordinated by one Trovix team, with a single project manager accountable through to handover.
Types of extensions we build
The footprint is usually decided by the shape of the house and the plot rather than by preference.
Side-return extension
Use otherwise underused side space to create a wider, brighter kitchen and ground floor.
Best for: Victorian and Edwardian terraces with a usable side return.
Side-return extensions explained
Wraparound extension
Combine rear and side space for the largest ground-floor transformation.
Best for: Homes with both usable rear depth and side-return space.
Wraparound extensions explained
Double-storey extension
Add living space downstairs and a bedroom or bathroom upstairs in one coordinated build.
Best for: Homes needing more space across two floors.
Double-storey extensions explainedSpace for everyday living
Kitchen extensions for more space and light
Create more room for cooking, dining and spending time together, with a layout designed around your home and everyday life.
A kitchen extension can take the form of a rear, side-return or wraparound extension, depending on your property and the space available.
See kitchen extensions in LondonIs an extension right for your home?
Most homeowners start with a problem rather than a plan. These are the signs an extension is the natural answer.
- You need more ground-floor living or kitchen space.
- There is usable garden depth or a side return to build into.
- The layout, not just the floor area, needs to change.
- You would rather improve the house than move.
Mainly need another bedroom? A loft conversion may suit the house better, and we will say so.
What a London extension costs
Typical project investment by type. Your own range depends on size, structure, glazing, drainage and finish.
Rear extension£60,000 – £120,000+
Side return extension£55,000 – £100,000+
Wraparound extension£80,000 – £160,000+
Double-storey extension£100,000 – £190,000+
Kitchen units, worktops and appliances are excluded unless specifically agreed for your project. Kitchen installation can be included by prior agreement.
Estimate My Extension Cost
Read the full London extension cost guide
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Three quick questions. You see an indicative range immediately — no email needed.
Question 1 of 3 · Extension type
What your construction estimate covers
See what the construction estimate covers and which items need a separate allowance. Your proposal will confirm the scope for your project.
Included in the construction scope
- Structure, structural steel, foundations and padstones
- Drainage construction and alterations on site
- Roof, glazing, rooflights and external doors
- First and second fix electrics and plumbing
- Plastering and screed, ready for decoration
- Coordinating Building Control inspections and completion documentation
Budgeted separately
- Architectural, structural engineering, planning, Building Control and Party Wall fees, unless we are specifically appointed to provide them
- Build-over applications and water-company fees
- Kitchen units, worktops and appliances, unless specifically agreed for your project; kitchen installation can be included by prior agreement
- Specialist joinery and premium finishes
- Garden reinstatement and landscaping
Decoration and floor finishes are project-specific. Your proposal states whether they sit inside the agreed contract sum or are budgeted separately, so nothing is assumed either way.
The Process
How your extension is delivered
One accountable point of contact coordinates the specialists your project needs, from the first conversation through to handover.
- 01
Discuss your plans
We discuss your property, goals and budget, then arrange a survey or site visit when appropriate.
- 02
Design and approvals
We develop the design or review your existing drawings, coordinating the technical work and approvals your project needs.
- 03
Scope, price and programme
We confirm the construction scope, specification, price and build programme before construction begins.
- 04
Build and handover
Your dedicated project manager coordinates the build, with weekly updates, final checks and handover.
Planning and technical coordination
Planning, building regulations, party-wall matters and structural and drainage checks are coordinated in the right order.
Living through the build
Many clients stay in the house for a rear or side-return extension, and a little planning makes that comfortable.
- Occupied areas, floors and routes through the house are protected.
- Access, deliveries and waste routes are agreed before the first day on site.
- A temporary kitchen is planned in advance where the kitchen will be out of use.
- Your project manager gives a weekly update, so you always know what happens next.
More completed London extensions
A selection of finished Trovix extensions across London, photographed on completion.
Mill Hill, NW7
Rear extension
Rear extension creating bright open-plan living with large garden doors.
Chiswick, W4
Kitchen extension
Open-plan kitchen extension with a central island and roof glazing over the dining area.
Why homeowners choose Trovix
Federation of Master Builders member
Member No. 170642. FMB membership involves professional checks and an inspection process before a builder is accepted.
A dedicated project manager
One accountable point of contact from the first conversation through to handover, with weekly updates during the build.
10-year structural warranty
Trovix provides a 10-year structural warranty for structural extension works. Project-specific coverage is confirmed before work begins.
Design, planning and build coordinated
Drawings, structural design, consents and construction are coordinated by one team, so nothing falls between the specialists involved.
Discuss your extension
We respond within 24 hours.
What happens next
- 01We review your details and respond within 24 hours.
- 02A short call to understand the property, the brief and the budget.
- 03If it looks right for both sides, we arrange a visit and set out the next steps.
Common Questions
Extension questions, answered
Ready to talk about your extension?
Tell us where your property is and what you are considering. We will review the details and respond within 24 hours.