Extensions Question

Replacing existing extension

i have a single storey extension at the moment at the rear of my house and it is 2m X 5m currently. we are looking to replace this with a single storey 3m x 5m with frenchdoors in between the house and the extension. i am looking for a quote for this (which i am going to post in jobs) but i was just wondering if this could be done for around £20,000 with electrics,plumbing,plastering etc.

7 Answers

Best Answer

This is always a difficult question but i would say from experience that as long as there are not issues with the groundworks (foundation - not too many trees close by or drains etc) and depending on the type of roof you are looking for (a flat roof is cheaper than a cut-pitched roof) then you should be able to do the job well inside the budget you are looking for.
We have done works like this in the past and the costs was in the region on £16K but this can be dependant on many things so is only a guide.
I hope that helps

Answered 11th Oct 2011

Eve Property Group

Member since 7 Feb 2011

It depends a lot on roof construction required , and what you come across in foundations , and a detail look at you're drawings but it's possible to build it all depends on finishing touches as this can raise the cost a lot . ....bob

Answered 11th Oct 2011

Affordable construction

Member since 28 Sep 2011

It probably can be done within your budget, but get at least 3 prices.

Answered 11th Oct 2011


Member since 29 Oct 2008


You will probably have quotes between £15-22k. Depending on the foundations you may be able to remove the roof and just add foundations and a new rear wall and tie into existing. If that is possible then cost may reduce slightly. Some builders will charge VAT on top depending on their turnover.

Best posting the job on my builder and have 3 builders come round to check the extension an dprovide a quote. But to answer your question you are in the right region with regard to costing.


John Briner
Briner & Sons Ltd

Answered 11th Oct 2011

Briner & Sons Ltd

Member since 2 Mar 2009

I would think you could get it done for that assuming it's not too complicated or has a fancy bathroom in it? A good rule of thumb is around £1000 per m2 floor area plus vat. Hope this helps, shaun

Answered 11th Oct 2011


Member since 6 Oct 2011

Yes, it could be done for a price in the range of £20,000 including flooring, plumbing, lights, etc. and it will normally take about 6 weeks. Anyway, that is highly depends on the Builders you are going to hire, as the price may sometimes vary from 15k to 40k. Thats why is best to post your job here, so you can get around 10 quotes and Companies (with lots of references) to compare.

Kind Regards,
Vass Y.

STAR Construction.

Answered 11th Oct 2011

STAR Construction

Member since 6 Oct 2011

Dear Sam,
From the sounds of things you will only be digging one new foundations and keeping the side walls,just extending them by one metre.
You will need to put steels in to support weight above the new french doors.
You will need to apply for planning or building regs but i would say that even with those costs you would be able to do this work for the monies you quoted.
regards geoff

Answered 12th Oct 2011

westbury building services

Member since 4 Oct 2011

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