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QuestionHow much would it cost to build a 3m x 9m single storey extension to a semi-detached house approximatley

the extension would be a small utility room, entrance lobby and extension to the existing kitchen. I would like an approx price for the structure/ roof and all new internal walls including any plastering works, electrical works and mechanical works.

11 Answers

Best Answer

Anything from £1000-£1700 per m2.Depends on where you are and who quotes it.There are lots of factors that may change it anyway.This wouldnt allow for foundation variances.If you needed to excavate to a depth of say 2.2m or have piling,this would cost you more money.As for electrics etc,we would need to know roughly how much is needed as i have had clients ask for 20 downlights in one room lol.Only real way of getting a good estimate or an exact quote would be to get a few tradesmen to visit the job.

Roc builders 16th Jan, 2012

I would think you are looking at around the £30000 mark, but obviously that would depend on what type of soil you have, existing footings and also if any trrees interfere with the footings. Hope this helps.

Solutions Carpentry & Building 16th Jan, 2012

At current rates the cost of your extension would be about £25 to £30k

Prestbury Developments and Refurbishments Ltd 16th Jan, 2012

depending on the material and the final quality of your fixtures and fittings i would say around £18,000- £24,000

banktop construction 16th Jan, 2012

Going from various previous jobs, The average cost is about £1000 sqm. This is to a plastered finish with plumbing, electrics, windows, plastering etc etc This is dependant on what finish you have inside the property, whether it be kitchen, Bathroom etc. If its just a basic room with just painted walls and carpet it will be cheaper, but its a good average cost to go by before you get too involved with builders and planning office etc. Hope this helps.

Empire Renovation 16th Jan, 2012

Difficult to price without seeing drawings & regs but a good guide would be between £1200-£1500 per m2 depending on spec.

m w building construction and property maintenance 16th Jan, 2012

Hi Rob,
I do not know where you live and area, the price could range from £800 to £1000 per metre square, so your extension should cost you £21600 or 27'000

kind Regards

Howard @ Ullyses

Ullyses limited 16th Jan, 2012

if you allowed £27,000 then you would,nt be far off.


hi Rob
you wouldn't be far out with budgeting 20k-25k as a finished plastered shell with skirting and doors. ready to paint

jd kent 16th Jan, 2012

Around £25000

Spencer Construction 17th Jan, 2012

32k plus but this is a rough guesstimate ,important factors inc ground conditions,access to site,spec of elecs and mechanical ect ect

substructure 16th Jan, 2012

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