Extensions Question

What is required to enable a builder to price a large one storey extension?

Please can you tell me what sort of plans are required to enable a builder to price a large one storey extension, including garage, utility, kitchen dining and sitting area. We have had an architect draw up and submit plans to the council but they don't show much detail, like thickness of walls, insulation required! They just show the size of the overall extension. Is this normal and should we be able to get a price from them??

4 Answers

Best Answer

There are two stages to the architects work. You have the planning drawings which are stage one. After planning is granted you will need working drawings which are stage two. These will show the details of how the building is to be constructed. Many Architects use CAD drawings which are good but my preference is the Architect that we have used for 15 years who still draws by hand and always includes all the details that you need in a very easy to read drawing.
You should also draw up a specification which would provide a written explanation and would form part of the contract for the construction of the extension. This would be the safest route to avoid problems. You will need professional help in the kitchen layout which can be difficult.
You will also need party wall agreements and I always use the same surveyor who will represent both parties if your neighbour will agree. You must have the agreements in place before you start.

Answered 23rd May 2012

Harwood Group

Member since 27 Feb 2012

What has your architect done that my 4 year old son cant then? Proper drawings are part and parcel in my opinion.Everybody knows what they are doing and getting and there are no grey areas.It will allow you to check whether the job is being done properly if you have no idea how these things work.I recently saw an "extension" constructed from 4x2 timber,loft roll as insulation,shed felt as a flat roof and no foundation.Needless to say it was completely worthless.

Answered 23rd May 2012

Roc builders

Member since 25 Aug 2011

Hi, I have priced and built extensions and have worked for and also know quite a few builders. Kitchens,bathrooms and any other fittings are usually priced separately according to spec. So the main pricing should be possible from the drawings you've got. Good luck with your project. Regards John

Answered 24th May 2012

total residential property services

Member since 17 Dec 2008


I give 'rough' estimates when looking at 'rough' drawings. When I have full working drawings to look at then I give a full quote.

You cannot possibly give a customer a full quotation without seeing a specification, measurements are nowhere near enough to go on. The materials being used form a massive part of working out figures so wait until you have this before trying to tie builders down to prices they give.

Answered 29th May 2012

R.Hughes Building and Conservation Ltd

Member since 25 Feb 2009

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