How much does a house extension cost?

Below are a collection of house extension prices. We haven’t covered double story, wrap around and loft conversions, but, if you send in your enquiry, we can provide build costs for any project. We can also obtain a fixed build cost from reliable local builders on your behalf after the final design is complete. Contact us so we can explain more

All example costs:

All estimated costs for house extensions cover building work, architectural plans and planning submission.

All example costs:

All estimated House Extension Costs cover building work, plumbing, electrical work, glazing, external doors, architectural plans, structural engineering, and planning submission.

Detached House Extensions

Small Flat Roof Extension

Size 3m x 3m

Estimated costs:

£22,995+vat

Architectural Plans & Structural Engineering Included

Large Flat Roof Extension

Size 9m x 3m

Estimated costs:

£49,995+vat

Architectural Plans & Structural Engineering Included

Gabled Roof Extension

Size 4m x 6m

Estimated costs:

£44,995+vat

Architectural Plans & Structural Engineering Included

Pitched Roof Extension

Size 7m x 3m

Estimated costs:

£39,995+vat

Architectural Plans & Structural Engineering Included

Semi-Detached House Extensions

Small Flat Roof Extension

Size 4m x 3m

Estimated costs:

£26,995+vat

Architectural Plans & Structural Engineering Included

Large Flat Roof Extension

Size 8m x 3m

Estimated costs:

£45,995+vat

Architectural Plans & Structural Engineering Included

Gabled Roof Extension

Size 7m x 3m

Estimated costs:

£39,995+vat

Architectural Plans & Structural Engineering Included

Pitched Roof Extension

Size 5m x 3m

Estimated costs:

£29,995+vat

Architectural Plans & Structural Engineering Included

Terrace House Extensions

Small Flat Roof Extension

Size 3m x 3m

Estimated costs:

£23,995+vat

Architectural Plans & Structural Engineering Included

Large Flat Roof Extension

Size 6m x 4m

Estimated costs:

£44,995+vat

Architectural Plans & Structural Engineering Included

Gabled Roof Extension

Size 5m x 4m

Estimated costs:

£41,995+vat

Architectural Plans & Structural Engineering Included

Pitched Roof Extension

Size 6m x 3.5m

Estimated costs:

£43,995+vat

Architectural Plans & Structural Engineering Included

Bungalow House Extensions

Small Flat Roof Extension

Size 4m x 3.5m

Estimated costs:

£29,995+vat

Architectural Plans & Structural Engineering Included

Large Flat Roof Extension

Size 9m x 4.5m

Estimated costs:

£71,875+vat

Architectural Plans & Structural Engineering Included

Gabled Roof Extension

Size 6m x 4m

Estimated costs:

£48,775+vat

Architectural Plans & Structural Engineering Included

Pitched Roof Extension

Size 7m x 3.5m

Estimated costs:

£47,995+vat

Architectural Plans & Structural Engineering Included

For more information on the design and build process please call our team or complete our enquiry form

Don't take our word for it

See what our customers are saying on Google

Boris
19:35 12 Nov 23
Kirkwood Design and Build Builders, Wickford did a fantastic job on our extension in Billericay. They helped with planning permission, design, and build. Professional company through and through. Given that we haven't done such a large project before, we were a bit nervous and had a lot of questions. Jamie and his team from Kirkwood Design and Build Builders was good putting us at ease and now that we are fully complete with all our work, we further appreciate how professional this company is. Would highly recommend.
Holly Luckin
09:29 11 Nov 23
Nothing was to much hassle and Jamie is lovely!
john rocke
11:33 09 Nov 23
Great company and very professional. Nothing was a problem, very helpful and will definitely use them again. Have already given their details to a friend of mine.
Dave Lynch
19:32 08 Nov 23
Work carried out to a very high standard, very pleased with the results.
Sharon Gormer
13:06 07 Nov 23
Very professional company, helpful and friendly staff.
Aaron Tutton
11:15 07 Nov 23
Great builders, very professional and perfectionists! Thank you for such an amazing job
Olly Tait
13:28 21 Apr 23
Jamie and his team were so profesional from start to finish and made the job a joy to watch our dream come together.Very knowledgeable and contactable throughout the process.Couldn't ask for a better outcome and value for money.Will definitely be recommending and 100% will use again!5 star!!!
Sandie
20:03 20 Jan 23
I highly recommend the Kirkwood team! Exceptional workmanship, clear communication, Jamie & his team have provided the utmost as a polite & professional team! Very satisfied customer, looking forward to planning our loft conversion this year with you guys! Many thanks!
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