Builders
Extensions, conversions, renovations and structural work, matched to a building contractor covering your part of London.
House Extensions In London, Costed Before You Commit
Rear, side return, wrap around and double storey extensions. Send the property type and the plan, and we route it to an extension builder.
Straight Answers Before You Send Anything
What this site is, what it costs you and what happens after you press send.
It Costs You Nothing
Sending an enquiry is free and puts you under no obligation. We are paid by the trade side, never by you, and no price on this site is ours to set.
Check Them Yourself
Whoever contacts you has a public record: a Google Business Profile, Checkatrade, Trustpilot or the Federation of Master Builders. Look them up before you commit.
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customer reviews and why this site does not show a score.
House Extensions In London
Extending in London costs more per square metre than almost anywhere else in the country, and the gap between a rough idea and a real budget is where most projects come unstuck. Design fees, structural engineering, party wall surveyors and building control all sit on top of the build price.
Tell us the property and what you are trying to add. We pass it to a builder who does extensions on that kind of house nearby. The foundations are usually the least predictable part, which is why groundwork is priced carefully, and quantity surveying is worth having on larger schemes.
Extension Types And Layouts
What you can build is set by the plot and the planning position. On a London terrace the side return is often the single most valuable move available.
- Single storey rear extensions
- Side return infill on a terrace
- Wrap around combining rear and side
- Double storey and over-structure extensions
Design, Approvals And Engineering
The work before the build is a project in its own right, and it runs on statutory timescales that cannot be shortened by paying more.
- Architectural drawings and a planning application
- Permitted development or prior approval where it applies
- Structural engineer's calculations for the openings
- Party wall notices to attached and rear neighbours
What Moves The Final Price
Quotes diverge mostly on things that are invisible on a floor plan. Asking about these four specifically makes two prices comparable.
- Foundation depth, trees and ground conditions
- Glazing specification and rooflights
- Drainage diversion and the existing soil stack
- Finishes, kitchen and the making good inside
How A House Extensions Enquiry Runs
Tell Us The Plan
Property type, what you want to add and roughly how big. Drawings if you have them; a description and photographs if you do not.
We Match A Builder
Side returns, double storeys and basements are not the same build. The enquiry goes to a contractor whose usual work is yours.
They Price It Properly
They visit, check access, drainage and the structure, and quote against a written scope with the exclusions named.
Find Out What Extending Will Cost
Send the property and the extension you have in mind, and an extension builder will come back to you.
The Kind Of Work That Comes Through
Surveying, structure, extensions and finishing across London property.
Where We Work
RCRO Building works across London and the towns and villages within 20 miles.
Towns And Villages
- London
- City of Westminster
- Islington
- Chelsea
- Battersea
- Holloway
- Brixton
- Peckham
- Fulham
- Archway
- Shepherds Bush
- Canary Wharf
- Stamford Hill
- Willesden
- Cricklewood
- Putney
- Streatham
- Stratford
- Chiswick
- Catford
- Canning Town
- Acton
- Wimbledon
- Tottenham
- Finchley
- Leytonstone
- Walthamstow
- Mitcham
- Wembley
- Beckenham
- Brent
- Morden
- Edmonton
- Eltham
- Croydon
- Barking
- Ilford
- Carshalton
- Enfield Town
- Chingford
- Greenford
- Harrow
- South Croydon
- Hounslow
- Welling
- Southall
- Thamesmead
- Heston
- Surbiton
- Sutton
- Becontree
- Purley
- Borehamwood
- Ewell
- Bexley
- Hayes
- Dagenham
- Feltham
- Banstead
- Ruislip
- Epsom
- Cheshunt
- Esher
- Romford
- Dartford
- Watford
- Uxbridge
- North Watford
- Staines
- Leatherhead
- Hatfield
- Hoddesdon
- Redhill
- St Albans
- Grays
House Extensions Questions
Do I need planning permission or can I use permitted development?
Single storey rear extensions often fall within permitted development on a house, within size limits, and larger ones can use the prior approval route. Flats have no permitted development rights at all, and conservation areas and article 4 directions remove them for houses too.
How long will the design, approval and build stages take?
The approvals are the part people forget. A planning application has a statutory determination period, party wall notices have their own notice periods, and both run before anyone is on site. Ask for a programme that shows all three stages.
What is included in the quoted price and what is excluded?
This is the question that decides whether two quotes are comparable. The usual exclusions are the kitchen, flooring, decoration, landscaping and anything found in the ground. Get them listed.
How much do architect, engineer and party wall fees add?
They are separate appointments from the build and they are not small in London, particularly where several neighbours each appoint their own party wall surveyor at your expense. Budget for them from the start rather than as an afterthought.
Which extension type gives the best value?
On a Victorian terrace the side return infill usually converts the least useful outdoor space into the most useful indoor space. On a wider plot a straight rear extension is normally simpler and cheaper per square metre.
What are the most common reasons budgets overrun?
Foundations going deeper than assumed, drainage that has to be moved, a change of mind after work has started, and a quote that excluded things the homeowner assumed were in it.
Related Building Work
Loft Conversions
Dormer, hip to gable, mansard and rooflight loft conversions, matched to a specialist covering your part of London.
Structural & Groundworks
Foundations, excavation, drainage, underpinning and structural alterations, matched to a groundwork contractor near you.
Quick Quote Online For A House Extension
Tell us about the job and we will put you in contact with a trade who does that work in your area.
- Costs you nothing and commits you to nothing
- Detail helps: drawings, photographs, a rough budget
- The trade quotes you directly, not us
Quick Quote Online
Takes under a minute.
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