Your browser isn't supported
It looks like you're using an old web browser. To get the most out of the site and to ensure guides display correctly, we suggest upgrading your browser now. Download the latest:

Welcome to the MSE Forums

We're home to a fantastic community of MoneySavers but anyone can post. Please exercise caution & report spam, illegal, offensive or libellous posts/messages: click "report" or email forumteam@. Skimlinks & other affiliated links are turned on

    • tillson
    • By tillson 30th Nov 06, 8:59 PM
    • 167Posts
    • 57Thanks
    Guide to house extension costs
    • #1
    • 30th Nov 06, 8:59 PM
    Guide to house extension costs 30th Nov 06 at 8:59 PM
    Don't forget the DIY and Home Improvement Deals Note

    I am in the process of planning a ground level extension to my house 3.5 metres x 4 metres apex roof. Is there a rule of thumbe for estimating building costs? For example /square metre formula.

    I just want to have an idea of roughly where the prospective builders should be giving their quotes.


    Last edited by Former MSE Andrea; 24-02-2011 at 4:36 PM.
Page 2
  • devmcc
    Me tooooo!!
    Hi - I am also looking to have an extension built in the next couple of months - looking for an additional room off the kitchen - sort of a conservatory type room but with a proper roof and walls!! Single storey... Any ideas on price for say around 13*14foot?? Also, has anyone had plans drawn up in the merseyside area?? Looking for a builder toooo !!!

    Any advice would be smashing!
    Hope you are all having a good weekend....
    • Ellidee
    • By Ellidee 18th Aug 07, 8:46 PM
    • 6,083 Posts
    • 16,824 Thanks
    Hi devmcc did you see my reply to your last post re plans ?
    Nothing is so fatiguing as the eternal hanging on of an uncompleted task. William James
    • Pauls
    • By Pauls 18th Aug 07, 9:19 PM
    • 737 Posts
    • 675 Thanks
    We're currently in the final stages of a 4*5m two storey build. Our builder stated 25k labour, and approximatley 10k for materials to put the thing up (we arranged our own electrician, plumber and kitchen/bathroom fitter who each charged individually)

    electrician was around 2k, we had a new fuse box and loads of switches/sockets etc. He also had to re-site/remove loads of stuff too.

    Plumber wanted around 2k, (had a bolier re-positioned, and a few rads installed) We've since found he's trying to rip us off, as yet he's had 1.5k and he's getting no more. He didn't do the job properly and left us with 3 separate problems with our boiler, and he caused all of them.

    Kitchen/Bathroom installer is costing around 5k, he's done a 2*1m shower room (previously part of a bedroom) a 4*5m kitchen, and a 2.5*2m bathroom. He's done all of the final fix plumbing, built & hung cabinets, tiled the floors, half tiled the bathroom & shower room, tiled the kitchen, and installed a new soil stack outside.

    All in all we were looking at 45k (though it's far to easy to ask for them to do other bits why there around (new patio laid, new 30ft block wall, new loft hatch/ladder etc etc which all add to the cost )

  • karel.develop
    scot extension
    just had an architect round & he's advised that we'll be looking at 1300.00 per m2 for the ground floor.. ? that doesnt include internal fittings, drawings etc. can this be right? the architect is not the one pricing the project - but he says these are the rates we can expect to pay.. it just seems crazy for a couple of walls & a basic roof.
    • tillson
    • By tillson 9th Oct 07, 9:16 AM
    • 167 Posts
    • 57 Thanks
    I have had six quotes for my single storey 4.3 x 3.4 metre house extension. Nothing complicated and straight forward. The cheapest works out at 2285 per square metre the most expensive is 3800 per square metre. This is just for a plastered shell with electrical / drainage and water services installed but no fittings.

    I find this quite depressing as everyone keep saying that 1000 to 1500 is about the going rate. I have put a lot of work into writing a detailed specification and having plans drawn up so that I am absolutely clear about what is required. It annoys me to see these property develeper type programmes on TV where they practically rebuild a wreck of a house for about 30K and very often this includes a sizeable extension to the house as well.

    Maybe I have been very unlucky and have just happened to have chosen the six most expensive builders in the world.

    I really can't bring myself to going ahead at these rates because unless anyone can tell me different, it would appear that I am being ripped off.

    I don't think I live in a particularly expensive part of the country (Derbyshire). If anyone can recommend a builder(s) for my 7th and 8th quotes, I don't mind being PM'd
    • Doozergirl
    • By Doozergirl 9th Oct 07, 9:47 AM
    • 27,718 Posts
    • 73,753 Thanks
    Property programmes are full of rubbish with regard to the actual costs because many of the people lie about how much stuff costs to make them look better. The people on programmes like homes under the hammer just make it up! that really is a pile of tosh.

    Admittedly, I'm a developer and don't even pay anywhere near £1000 including fittings but £3800 should get you something totally state of the art including fittings!!

    I don't think Derbyshire should be expensive - the Midlands is pretty cheap compared to almost everywhere. I could send my H from here to project manage for you and pull it in at something more realistic! :rolleyes:

    Out of interest, to save me doing the maths, what were the prices of the actual quotes?

    EDIT: I couldn't wait - between £33,000 and £50,000?!
    Last edited by Doozergirl; 09-10-2007 at 9:51 AM.
    Everything that is supposed to be in heaven is already here on earth.
  • BobProperty
    .....I don't think I live in a particularly expensive part of the country (Derbyshire)....
    Originally posted by tillson
    Unfortunately, you might be in an "expensive part". Some parts are upmarket commuter land for Sheffield, you'd hardly call Buxton "cheap" too. I would also consider the following points:
    Planning may require you to have stone where brick would be normal elsewhere in the country. In fact most of the north of Derbyshire that I'm familiar with, I would say is stone not brick.
    You may live somewhere "out of the way". Making it a PIA to get to for the builder and to deliver materials to.
    A house isn't a home without a cat.
    Those are my principles. If you don't like them, I have others.
    I have writer's block - I can't begin to tell you about it.
    You told me again you preferred handsome men but for me you would make an exception.
    It's a recession when your neighbour loses his job; it's a depression when you lose yours.
  • Will_it_make_me_rich
    Our extension should be finished this week, its taken a little longer than expected but I can't complain too much as it was a good price.
    The only thing for us to do now is tile the kitchen and paint through out.

    I also live in south derbyshire, Tillson where abouts are you in derby?
    If you want I could give you the details of our builder.
    Who have you had quotes from?
    • tillson
    • By tillson 9th Oct 07, 2:24 PM
    • 167 Posts
    • 57 Thanks
    Thanks Will_it_make_me_rich. I live to the North East of Derby in West Hallam. I don't know if that is close enough to you for any of your builders to be interested. If you are within range, I would be gratefull for any building company suggestions.

    vbmenu_register("postmenu_6506947", true);
  • Will_it_make_me_rich
    I would be gratefull for any building company suggestions
    Check your private messagers.
  • Leigh-Anne 60
    I live in devon and have just finished (all but) my extension - 24k, its approx 5m x 4m - This includes the fitting of a new kitchen(not provision of) re-used UPVC doors/windows. 2 new walls only as used party wall and existing house wall

    When i got my quotes in - they ranged from 31k to 45k, way beyond my budget. So opted for 'a friend of a friend' at 25K....... A long story for another thread but im now taking him to court.

    In my experience you get what you pay for - I opted for the cheapest and got the builder from hell (well maybe not that bad - the extension is still standing ) But please check out their previous work.

    Also when you price up include additional extras, paint new curtains, new flooring etc - i would estimate that this added on about 2k to our cost.

    Also cost of architect, planning and buidlings regs - this was around another 3.5k

    So a bit of change from 30k.........From an initial overall budget of 20k



    PS - If any of you are in Plymouth and want to know what builders NOT to use, drop me a PM
  • never enough
    Agree with Doozer girl that some of the figures quoted on these programmes are just rubbish. They also often have teams of bods to draft in to do work & I bet they're not getting standard rates.
    If you've had lots of quotes coming in at roughly similar prices then that's what builders are likely getting in your area. Obviously they could be trying it on, or maybe they're so busy they just don't want the work, but if that's what other people are paying then you'll need to too. There are lots of ways of saving money on fixtures & fittings, so maybe you can save some money there? I guess you need to weigh the costs of an extension against those of moving, to decide how much it's really worth to you.
    • katepnlo
    • By katepnlo 10th Oct 07, 8:42 AM
    • 391 Posts
    • 189 Thanks
    Any idea what the cost is down in south east, I am not far from Dover.

    Still trying to figure out if we should extend or move..worrying a bit about price now!!
    • Canucklehead
    • By Canucklehead 10th Oct 07, 12:03 PM
    • 6,262 Posts
    • 3,371 Thanks
    Any idea what the cost is down in south east, I am not far from Dover.

    Still trying to figure out if we should extend or move..worrying a bit about price now!!
    Originally posted by katepnlo
    The price down here in East Kent varies could get the trades in for quotes but if you don't have planning/plans for your extension you might get a a bit of a rep as a timewaster (my OH can usually get the lowdown from other trades about these types but unfortunately one or two slip through the screening process eg. in a local plumbers' merchant in the spring he heard about one property owner in Margate who had at least 14 plumbers in to look at a project and give a free quotation...the property remains empty and untouched and the owner on the carp list. Up here everyone seems to be very busy....long waiting times for clients at the moment

    To the OP: the OH and I find the property porn e.g. Homes under the Hammer great for a laugh but these shows,as said previously, do give people inaccurate info about renovation/extension costs and the skills/registration/compliance required to complete works to a high (and more marketable) standard.

    Good luck.

    Ask to see CIPHE (Chartered Institute of Plumbing & Heating Engineering)
    • level200
    • By level200 30th Sep 08, 7:45 PM
    • 268 Posts
    • 230 Thanks
    Very roughly 1000/m2
    Originally posted by BobProperty
    How can they charge per squared meter as an extension is in effect a shell, surely the squared meterage does not include the empty space?
  • ormus
    its just a rule of thumb guide. a 3 walled extension with a flat roof will contain so many sq metres. hence for a 4x4 m extension the guide cost will be about 16k.

    this is just for an empty shell with floor/roof/PB walls and ready for painting.
    any fancy bathrooms etc will add to that cost.
    Get some gorm.
  • talkinpeace
    My extension (two storey side, one and two storey rear, loft conversion, steels everywhere) came in at £1550 / sqm all in
    so from building to painted, carpeted, tiled and finished
    I saved money by getting subbies in individually
    • Stevie1
    • By Stevie1 3rd Oct 08, 9:15 AM
    • 193 Posts
    • 91 Thanks
    We've been getting quotes for our extention recently. Have had so far, about 6 or 7 and the price differences are HUGE. About £25K between the cheapest and most expensive.

    Not only that, we get the feeling that builders are bracing themselves for tough times (or perhaps, taking the mickey), because we have been quoted very high prices for a very basic building shell (we have own trusted tradesmen; plasterer, electrician etc). So much so, we are thinking of getting it all done by separate tradesmen.
    Last edited by Stevie1; 03-10-2008 at 9:21 AM. Reason: sp
    • latecomer
    • By latecomer 3rd Oct 08, 9:57 AM
    • 4,619 Posts
    • 2,626 Thanks
    We are looking at extension plans right now and have been getting some wild estimates just for the structural work. Need to get the plans finalised and then see what we can do ourselves as we are on a tight budget.
  • scwarlem
    Hi folks, has anyone got an idea on the average costs of a two storey extension? So far there have been suggestions for what i take to be a single storey, ranging from 1000 upwards. Does anyone know if this is true for the second storey, or is there a second, separate estimate. :confused:
    I live in Northern Ireland, so if anyone has any ideas of any builders that would be appreciated. I already have an extremely good plumber (pm if interested), and he has said he can get me a tiler. But i need the other construction boyos.
    The extension will hopefully make a larger kitchen, downstairs toilet; a third bedroom and bigger bathroom upstairs. And, depending on costs, may get an attic conversion.
    Havn't applied for anything yet, but hopefully there should be no problems with planning as my neighbours (semi) got an extension done last year, albeit a single storey.
    Dont suppose anyone has an idea about asbestos tiles? Will have to retile during renovation work.
    Thanks in advance for any help you can give.
Welcome to our new Forum!

Our aim is to save you money quickly and easily. We hope you like it!

Forum Team Contact us

Live Stats

193Posts Today

2,935Users online

Martin's Twitter