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Hi, what is the basic prize of an extension per sq m ? what does it include ? how do you know if the tradesman chosen doesn't over charge you? and how to you pay the job before or end of the work .


7 Answers from MyBuilder Extension Builders

Best Answer


£1,000-1,800 per sq met.
You will get foundations , walls ,doors,windows and a roof allong with
so for 1,000 you will get the bare minimum:-
basic electric
basic plumbing
basic everything, as you go up the sq m charge the products get better quality
for bespoke or hand made itens the cost will be over the 1,800 mark.
If you were to use my company the charges will be as followes
all planing and drawing feas will be paid up front
you will pay £250 deposit to secure your start date
you will then pay schedualed part payments from then onwards.
Start of works payment made
2 weeks in another paymeny
2 weeks in another payment
final payment upon compleation and signing off of all schedualed works.
you get the idea!! This plan method helps keep both partys safe.
Never part with all the contract cost up front "NEVER"

regards Ashley


Answered 9th Mar 2016


it is hard to judge the price of an extension on factors of sq m as there are numbers of contributing factors. I will try to cover it the way we prepare quotes.

1. if the extension is small then price per sq m will be higher than bigger extension;
2. as a very general rule you should be looking at costs between £75 - £150 per sq ft. this will include finished room so electrics, plumbing and decoration done, but will exclude fitting of the kitchen and/or bathroom and mostly will exclude flooring or tiling;
3. if extension is to be higher than one storey then it you should also add sq ft of first storey to the calculation but at slightly lower rate. And again it is hard to say by how much as there are too many things to consider;
4. another contributing factor is the quality of finish you would like to achieve. For instance if you would like to have rooms like photos from Home And Garden magazine then you might not fit within the budget I have given above;
5. location and local restrictions do contribute to the price, for instance if your house is located where a parking is difficult and the only way of arranging for a skip would be to suspend a bay in front of the house, you would have to expect to pay extra for this. We have done a job in Fulham London where cost of skips and parking summed up to over £10k.

Hope this will help, if you would like to get much more accurate quote for your project please give me a shout.



Answered 9th Sep 2013

In the South-East of England ( outside London ) the cost of building an extension is approx £1000 per sq.metre of the floor area. This should cover everything from foundations to finished plaster, including basic electrics and plumbing. It won't include fitted kitchens or bathrooms. If there are existing buildings ( garage or outhouse ) to be demolished, this will add to the cost.
There is no guarantee that your chosen tradesman isn't overcharging - the best way to ensure you are getting a good job for a fair price is to ask several builders to quote for the job, and compare the quotes. Get them to itemise the work they are quoting for to ensure that they going to do the complete job. Don't necessarily go for the cheapest quote particularly if it is much lower than the others, it is better to pay a bit more to get a good finish. Ask to see other jobs they have done.
Don't pay huge amounts of money upfront, any reputable builder will ask for only a small deposit when commencing work, and will provide a stage payment schedule detailing when further payments are to be made. Only make the payments if you are happy with the work carried out, and always hold back some money until every item is completed to your complete satisfaction, the builder has cleared away all surplus materials and other detritus, and the Local Authority Building Control have signed off the project and issued a Certificate of Completion


Answered 4th Jun 2011

hi depending on where you live prices vary a good price per sq meter would be £1200 this should include 1 window 1 rad 1 light and 3 sockets and 1 door.

payments small deposit then a payment after the footing and slab is down then 1 a wall plate just before the roof then when roof is on and then completion

hope this helps


complete building


Answered 4th Jun 2011

i dont think there is a basic price for any job as they can vary massively, by getting 3-4 genuine quotes you will no whos over charging, or under quoting to get the job, that probably wont be finished to a high quality. personally i ask for a deposite to start the job but never take the full amount till its complete and everyones happy with the work.


Answered 4th Jun 2011

hi, you should work on £1000 to £1500 per sq m and covers everything to a finished standard inside and out but it does depend what specification you want / where in country you live etc (doesnt include kitchen if kitchen extention)

With regards to overcharging and pyment - agree a specification and timescale between you and builder ten draw up a schedule of works contract and agree stage payments - never pay up front!!!!!


Answered 4th Jun 2011

depends some builders may want materials cost up front, but you could buy them. you might have stage payments, so walls up pay say 25%, roof on pay 25%, electrics in and signed off pay 25%, work finished and all paper work handed over pay final amount, just examples, but you should never pay everything upfront even if its friend or family member anything can happen.
it could be £1,000 + per meter Square depending on the work involved this should include materials, labour and whatever else, i personally only use this a ruff way to estimate, on the spot, i would then go off and work out a proper quote as this could go up or down depending on whats involved


Answered 4th Jun 2011

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