Services/Construction, structural & civils

House extensions in West London

Side return, rear and wrap-around extensions — drawn, priced and built by one team, from the first survey to the finished kitchen.

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12–20weeks on site, typically
In-housedrawings and calculations
Party wallprocess handled for you
Onecontract, start to finish

Listed, vetted and reviewed on

Ogival Ltd, registered in England & Wales no. 15191703 · Public liability insured · NICEIC registered electrical work · Gas Safe registered plumbing and heating

An extension is the most common job we're asked for and the one where the money is most often wasted. Not on the kitchen — on the three weeks lost waiting for a structural engineer, the drainage run nobody surveyed, and the party wall award that should have started two months earlier.

What usually goes wrong

The programme is set by ground conditions and the party wall, not by the kitchen you've chosen — and those are the two things most quotes gloss over.
Drawings done by one company and built by another leave a gap, and the gap is where the arguments live.
Drainage. Almost every London extension crosses a drain run, and finding that out after the slab is poured is expensive.

House extensions by Ogival in West London

Extensions and structural openings across West London

What's included in a house extension job

Our bricklayers, carpenters and groundworkers handle the whole of it, so there's no second company to chase and no gap between trades for something to fall through.

Site survey and feasibility
Architectural drawings
Planning application or permitted development
Structural calculations
Party wall award process
Building control
Groundworks and foundations
Drainage alterations
Steel beams and padstones
Roof, glazing and rooflights
First and second fix
Kitchen installation
Decoration and snagging

Send a photo of the back of the house

A wide shot from the garden and one of the side return tells us most of what we need — access, levels, drains and how much you can realistically build.

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At a glance

ServiceHouse extensions
GroupConstruction, structural & civils
Typically12–20 weeks on site
CoveringWest London
BasedLondon W10

Why Ogival

25 years in London construction
Thirty-one trades under one contractor
Drawings and calculations in-house
A written schedule of works and payments
NICEIC and Gas Safe registered

How we work

Options

Which kind of extension suits your house?

Side return

Fills the narrow alley beside a Victorian terrace. Adds width where the kitchen is always too narrow, and usually the single best return on a London terrace.

Rear extension

Straight out into the garden. Simplest structurally, and the one most likely to fall under permitted development.

Wrap-around extension

Side return and rear combined. The biggest gain, the biggest steel, and the one that needs the most careful thought about light.

Two-storey extension

Bedroom above, living space below. Almost always full planning, and a party wall award with everyone attached.

Quickest way to get an answer

Send a photo of the back of the house.

A wide shot from the garden and one of the side return tells us most of what we need — access, levels, drains and how much you can realistically build.

No form, no callback queue, no salesman. Emanuel looks at it himself and tells you what he sees — including the times the answer is that you don't need us.

WhatsApp a photo Call 07428 135100

OOgivalonline

Hi — thinking about a side return on our Victorian terrace in Hammersmith. Photo of the side alley attached.

Thanks. That alley's about 1.8m by the look of the brickwork, so you'd gain a proper kitchen width.

Two things I'd check on site: there's a gully by the back door, so we may need to divert the drain, and you'll need a party wall award both sides.

Rough programme 14–16 weeks on site once drawings and planning are through. Want me to come and measure up?

Message

A typical exchange. Usually answered the same day.

How it runs

How a house extension job runs, stage by stage

Four stages, and you'll always know which one you're in.

01
Site visit and feasibility
We walk the garden and the party walls, look at levels, drains and access, and tell you what's realistic before anyone draws anything.
02
Drawings, planning and party wall
Architectural and structural drawings, planning or permitted development, building regs and the party wall process.
03
Schedule of works and payments
A written breakdown and a payment schedule tied to stages, so you can see where the money goes.
04
Build, snag and hand over
Groundworks through to decoration with one site manager, then snagging, certificates and sign-off.

Extensions and structural openings across West London

Recent projects

Extensions we've built

Extensions and structural openings we've built in W6, W12 and WC2.

Maida Vale, W9Read the case study →

Shepherd's Bush, W12Read the case study →

Providence Villas, W12Read the case study →

All our case studies

Permissions

Do I need planning permission for an extension?

Often not. A single-storey rear extension can frequently be built under permitted development, but the limits are specific and much of West London sits in a conservation area where those rights are restricted. We establish which route applies at the first visit, in writing, before anything is designed.

Rules change and every property is different. We confirm what applies to yours in writing at the survey rather than leaving you to guess.

Permitted development has depth, height and materials limits — and they differ for terraced, semi-detached and detached
Conservation areas and listed buildings restrict or remove permitted development rights
Building regulations approval is needed either way, for structure, drainage, insulation and fire
A Party Wall Award is normally required where you build against or near a neighbour's wall
Flats and maisonettes have no permitted development rights at all

Budget

How much does a house extension cost in London?

We don't publish prices, because a number without a survey is a guess and you'd be right not to trust it. These are the things that actually move it.

Ground conditions and how deep the foundations have to go

Whether the drainage has to be diverted

The span of the opening and therefore the size of the steels

Glazing — rooflights and sliding doors are rarely the cheap bit

The kitchen specification, which is entirely yours to control

Access: a terrace with no side gate changes everything

How long does a house extension job take?

12–20 weeks on site on site for a typical job in West London, though the drawings, permissions and party wall process before it can add longer. We give you a written programme with the quote so you can see both.

A site visit and a written quote cost nothing, and the quote comes with a written schedule of works so you can see what every stage is for.

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Before you appoint anyone

Four questions to ask before you hire anyone for house extension work

Ask them of us as well. The answers tell you more than the number at the bottom of the page — and a contractor who can't answer them quickly is telling you something too.

Ask us right now

01
Ask who does the structural calculations, and whether they're in-house or a company you'll be chasing
02
Ask to see a written schedule of works and payments before you commit to anything
03
Ask what happens when the drainage isn't where the drawing says it is
04
Check the party wall process has actually started before the programme is agreed

What clients say

Word of mouth, written down.

Left by Ogival customers on MyBuilder and TrustATrader

I have used this company for years for many different jobs including painting my whole house, tiling my bathroom, laying flooring, astroturfing my garden and putting up fences. Very knowledgeable, professional and polite. If you want a company that care, I'd stick with Ogival.

★★★★★Repeat client, MyBuilder

Ogival has a friendly and professional team. Our new bathroom looks great and we're very happy with the choice of products used and the quality of their work.
★★★★★New bathroom, MyBuilder

Great communication, polite workers and excellent tidying up afterwards. Definitely recommend.
★★★★★Painting and maintenance, MyBuilder

They were professional, polite, easy to get hold of and easy to deal with. They did a great deal of work for me including building an internal wall, moving a bathroom, carpentry, electrics and plumbing, they re-rendered my balcony, relaid the decking and repainted the whole flat.
★★★★★Full flat refurbishment

I have used this company for years for many different jobs including painting my whole house, tiling my bathroom, laying flooring, astroturfing my garden and putting up fences. Very knowledgeable, professional and polite. If you want a company that care, I'd stick with Ogival.
★★★★★Repeat client, MyBuilder

Ogival has a friendly and professional team. Our new bathroom looks great and we're very happy with the choice of products used and the quality of their work.
★★★★★New bathroom, MyBuilder

Great communication, polite workers and excellent tidying up afterwards. Definitely recommend.
★★★★★Painting and maintenance, MyBuilder

They were professional, polite, easy to get hold of and easy to deal with. They did a great deal of work for me including building an internal wall, moving a bathroom, carpentry, electrics and plumbing, they re-rendered my balcony, relaid the decking and repainted the whole flat.
★★★★★Full flat refurbishment

He replaced eroded bricks and once the wall was dry replastered ready to decorate. Work was delayed because he uncovered wet rot in the ceiling joists. He fixed the cause of those leaks. Throughout this saga Ogival has been professional, reliable, extremely thorough and honest.
★★★★★Exterior leak repairs, MyBuilder

I found them really helpful and honest. They went out of their way to help. They also finished on time and left the place spotless.
★★★★★Renovation, TrustATrader

I decided to go with them as I liked their ideas and Emanuel knew what he was talking about. He made floor to ceiling units, redecorated my room and laid laminate flooring. I have no hesitation in recommending them.
★★★★★Bespoke joinery, TrustATrader

Good finishing.
★★★★★Mohammed D., MyBuilder

He replaced eroded bricks and once the wall was dry replastered ready to decorate. Work was delayed because he uncovered wet rot in the ceiling joists. He fixed the cause of those leaks. Throughout this saga Ogival has been professional, reliable, extremely thorough and honest.
★★★★★Exterior leak repairs, MyBuilder

I found them really helpful and honest. They went out of their way to help. They also finished on time and left the place spotless.
★★★★★Renovation, TrustATrader

I decided to go with them as I liked their ideas and Emanuel knew what he was talking about. He made floor to ceiling units, redecorated my room and laid laminate flooring. I have no hesitation in recommending them.
★★★★★Bespoke joinery, TrustATrader

Good finishing.
★★★★★Mohammed D., MyBuilder

Read them in full on MyBuilder, TrustATrader and Houzz.

Where we work

House extensions across West London.

Extensions across Kensington, Chelsea, Notting Hill, Hammersmith, Fulham and Shepherd's Bush — almost all of it conservation area work on Victorian and Edwardian stock, where the planning route matters as much as the build.

Ogival, W10 5DW
Everyday patch, within 10 miles
Regular work, 10 to 20 miles
By arrangement, out to 30 miles

Where we do this most

Outside this? Ask anyway. We'll tell you honestly whether we're the right firm for the journey.

Questions we get asked

What everyone asks before extending.

The questions that come up on the phone most often, answered the way we'd answer them on site.

Do I need planning permission for an extension?

Often not. A great many single-storey rear extensions fall under permitted development, but it depends on the property, whether it's been extended before, and whether you're in a conservation area — which much of West London is. We check this at the first visit rather than assuming.

How long will my house be a building site?

Twelve to twenty weeks on site for a typical single-storey extension. The drawings and permissions before it can add two to four months, which is why we start that process early.

What is a party wall award and do I need one?

If you're building against or near a shared wall you'll need to serve notice on your neighbours and usually agree an award with a surveyor. We handle the process. Starting it late is one of the most common causes of delay.

Can we stay in the house during the works?

Usually yes for a rear extension, because the existing wall stays up until late in the programme. We'll be honest at survey about the weeks where you won't have a kitchen.

The rest of what we do

House extensions, and thirty other things we do

Most jobs pull in more than one of these. Having them all under the same roof is what stops a project stalling for three weeks waiting on somebody else's diary.

Construction, structural & civilsStructural alterations

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Interiors & finishingKitchens

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Construction, structural & civilsGroundworks & civils

Renovations & refurbishment in West London

Construction, structural & civilsRenovations & refurbishment

Interiors & finishingBathrooms

See all thirty-one services

Start here

Tell us what you're planning.

A site visit and a written quote cost nothing. If the job isn't right for us, we'll say so and point you somewhere better.

Free, no-obligation site visit and written quote
You deal with Emanuel, not a sales rep
A written schedule of works and payments before anything starts
Covering Kensington, Chelsea, Hammersmith and Fulham

07428 135100 info@ogival.co.uk

WhatsApp a photo See the case studies

House extensions in West London

What usually goes wrong

What's included in a house extension job

Which kind of extension suits your house?

Side return

Rear extension

Wrap-around extension

Two-storey extension

Send a photo of the back of the house.

How a house extension job runs, stage by stage

Site visit and feasibility

Drawings, planning and party wall

Schedule of works and payments

Build, snag and hand over

Extensions we've built

Do I need planning permission for an extension?

How much does a house extension cost in London?

How long does a house extension job take?

Four questions to ask before you hire anyone for house extension work

Word of mouth, written down.

House extensions across West London.

What everyone asks before extending.

House extensions, and thirty other things we do

Tell us what you're planning.

Contractors, trades and suppliers — let’s talk.

Tell us what you do