House extensions built to a fixed price and a fixed programme
From a 20 square metre kitchen extension to a full double storey wraparound, we take the drawings, price them properly and build them under one contract with one project manager. FMB registered, fully insured, working across London, Surrey and Kent.
The extensions we build
Every extension is priced line by line from your drawings and built under one fixed price contract. Groundworks, structural steel, roofing, glazing, first and second fix, plastering, decoration, Building Control liaison and a written workmanship guarantee are all included. Open each project type below to see what is involved.
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The most popular project we do. Open plan kitchen and dining space with large glazing, a level threshold to the garden and roof lights to bring in daylight. Many fall under permitted development, and we will tell you at the site visit whether yours does. Typical build time 10 to 14 weeks.
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Reclaims the dead alley beside Victorian and Edwardian terraces and turns a narrow kitchen into a wide, bright family space. Tight access and stitching the new structure into the old is where experience matters, and it is work we do every month.
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Extra bedroom and bathroom above, bigger living space below. Better value per square metre because the roof and foundations do double duty. Usually needs full planning permission, which we can handle with your architect. Typical build time 14 to 20 weeks.
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Turn unused space into a studio, home office, gym, playroom or annexe. Often no planning permission is required. We insulate, damp proof, rewire and finish to the same standard as the rest of the house, with Building Control sign off at the end.
How it works
Site visit and brief
We walk the property with you, talk through what you want and what the building will allow, and give you an honest early view on budget.
Design and costing
We work with your architect and engineer, or bring in ours, and turn drawings into a fixed price proposal you can compare line by line.
Build
A named project manager, a written programme, weekly updates and a tidy site. Stage payments only for work that is finished and inspected.
Handover
Snagging completed, Building Control certificate issued, and your written workmanship guarantee in your hand.
How we price
What extensions cost
Honest guide figures so you can plan. These are build costs per square metre of new floor area, excluding VAT, design fees and kitchens or bathrooms beyond a standard allowance.
Single storey extension: from around £2,500 per m² for a good specification, £2,900 to £3,300 per m² for an excellent specification.
Double storey extension: from around £2,400 per m² for a good specification, £2,800 to £3,200 per m² for an excellent specification.
Side return extension: from around £3,100 per m². Tight access and stitching into the existing structure add cost.
London and the South East typically carry a 10 to 35 percent premium depending on access, parking and site conditions. A typical 30 square metre kitchen extension lands between £66,000 and £99,000 plus VAT. We give you a line by line fixed price after a site visit so there are no surprises.
Tell us about your extension
Send us your drawings if you have them, or just describe what you want to do. We reply within one working day and can usually visit within the week.
Email sales@mcsrenovations.co.uk
Federation of Master Builders member 170434. Fully insured. Written workmanship guarantee on every project.