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From £43,200
Sebastian Banga
Member since August 2025
Banga decoration. Is Base in south London for number of year Banga decoration is a small company. Wich provide an excellent job to the custom...
John Mcdonagh
Watch our short video highlighting all our expertise and services here:
more than 10 y...
Glenn Miller
Relax... you have found a reliable extension builder in SE25. Glenn Miller Builders Limited is a friendly and reliable company based in SE25 who co...
Experienced extension builder ready to quote for your work. Aviemore Building Contractors Ltd is the best extension builder in SE25. No obligation ...
Stuart Bogazzi
Working as a builder for over 20 years now.
Family run business
Can sort any problem out and help build your dreams.
Experienced extension builder ready to quote for your work. Bhagtana & Co Construction is the best extension builder in SE25. No obligation free qu...
Trusted and professional extension builder in SE25. Experienced in all extension buildering work and keeping within budget and on quote. K S BUILDE...
Need to find an Extension Builder near you for all your extension buildering work?
VDL Construction Ltd provides a local, trusted extension...
Experienced extension builder ready to quote for your work. Top Builders is the best extension builder in SE25. No obligation free quotes and many ...
Need to find an Extension Builder near you for all your extension buildering work?
Howland Building Services provides a local, trusted exte...

In SE25, prices for dormer loft conversions range from £41,568 (Oaksure Construction based in CR0) to £43,200 (Banga Decoration based in CR7), but how much your conversion costs will vary depending on the size of your property, how easy access to your roof is and what you want to use the space for.
The best way to get an accurate price is to compare quotes from extension builders in SE25. Post your job on HaMuch now and we'll put you in touch with available extension builders.
"Build a dormer loft conversion" - BR3, job posted 01/01/70
Whether you’re looking to extend your kitchen with a side return extension or you want to convert your basement into a liveable space, read our cost guides to get an idea of how much each project costs before getting a more accurate quote from our database of reliable tradespeople.

Underpin a building - £17,774

Two storey extension - £88,412

Build a timber frame extension - £26,274

Build a swimming pool - £81,274

Single storey extension - £60,488

Side return extension - £44,587

Install an RSJ - £2,474

Outbuilding - £10,274

Build a Mansard loft conversion - £52,274

Loft conversion - £36,323

Build a kitchen extension - £42,274

Hip to gable loft conversion - £42,274

Granny annexe - £87,274

Garden office - £10,274

Convert a Garage - £16,274

Garage - £18,774

Build a flat roof extension - £22,274

Build a dormer loft conversion - £42,274

Concrete foundations - £6,524

Convert a bungalow loft - £29,274

Convert a basement - £40,587