Rough estimate of building an extra room?

edited 30 November -1 at 1:00AM in N. Ireland
6 replies 1.9K views
justaquestionjustaquestion Forumite
737 Posts
edited 30 November -1 at 1:00AM in N. Ireland
Hello folks,

I know that it is a very difficult thing to do, but what roughly should I expect to pay a builder to add a gable side extra room, its flat ground and I would like a small pitched roof, not flat.

Though I am not really in the know, I was estimating that the materials alone would cost no more than £3k, blocks some timber and slates don't cost the earth, hiring workmen maybe £7-8k at max, and would think that a builders fee project managing fee should be no more than £5-6K giving a total of £16-17k.

Maybe you have had something similar done and can comment on my own estimate?

Thanks

Replies

  • Owain_MoneysaverOwain_Moneysaver Forumite
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    You've forgotten the foundations :-( and the 10% contingency which will be used up.

    Roughly £1000 per square metre, but smaller ones will be disproportionately expensive as there is a certain amount of overhead that isn't related to the size of the project.

    Also planning and building control fees and plans drawing may not be cheap.
    A kind word lasts a minute, a skelped erse is sair for a day.
  • Thanks for reply. When you refer to "and the 10% contingency which will be used up" what exactly are you referring to here?

    As the room will probably be about 11x11 feet, can only visualise in those so showing my age, and going on £1k a metre as you say, first impression are that it might work out even cheaper than I thought, I did run it though an online calculator as well but cant remember the link.

    I am not taking the drawings, building control or planning fees into consideration here, Seems I am exempt from the £285 planning fee anyways because it fits into permitted development, but still need plans drawn up as its over 10 sq metres for building control.

    Any tips as to how to deal with a builder as regards when to what times to pay him the money etc?

    Thanks a lot
  • KiwiCoopKiwiCoop Forumite
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    I'd say your estimate isn't far off, assuming access is okay. Get a good detailed drawing done for quotation purposes. As for payment, the job will probably take 3-4 weeks so a small builder would probably want a payment at about halfway (based on his progress) and the rest on completion (or most of it subject to snagging and appreciate there will likely be variations).
  • suki1964suki1964 Forumite
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    Be sure of your existing foundations before going ahead

    We have just completed a 4x4 metre extension ( self build) and were dismayed to find our foundations were 4.5 metres down, we had to have it pilled which took a lot out of the budget

    Plans for the building control were £1k and another couple of hundred for the engineers steel report
  • Hello there, we are thinking of doing an extension (pitched roof), too, behind the kitchen of around 12 square meters, with a small patio area. Got one quote of 30,000 which seems dear to me!
  • suki1964suki1964 Forumite
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    sufiwho wrote: »
    Hello there, we are thinking of doing an extension (pitched roof), too, behind the kitchen of around 12 square meters, with a small patio area. Got one quote of 30,000 which seems dear to me!

    Very

    My husband went to someone who was quoted 55k for less :(
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