Quote for single storey rear extension

A question about : Quote for single storey rear extension

We've recently been quoted 55k for a single storey brick built rear extension measuring 7.5m x 3m. The project would include knocking down one internal wall, plus the rear wall of the house to make one large open plan kitchen/family room. This cost does not include the new kitchen units and appliances which we are arranging separately. Also we wanted underfloor heating, which we are waiting for the price on.

The build would include 2 sets of bi-fold doors and 3 velux windows set into the vaulted roof. Builder would project manage entire build, including plumbing, electrics etc.

Having researched the potential cost prior to having costly plans drawn up (speaking to builders for ball-park figures, reading up and researching on the internet), we were expecting a cost of approximately 30-35k so were completely floored by the quote which came thru! This works out at over 2.2k per sq m. We will be obtaining other quotes for comparison but wondered if we are way out of touch when it comes to costs or whether this builder is having a laugh at our expense?

Best answers:

• Get a few more quotes and you will realise there is infact a lot of unseen work when doing a job like this. Builder would have to do extension, roof it, put in outside windows and doors, then seal off the inside of wall to be taken down. Then they could take the wall down, unseal it and do the plumbing and electrics etc.....It is alot of work, if its a builder with a good reputation, lots of references and can break down the cost for you to make it clear where the money is going then it will be alot easier to realise its not THAT bad a quote....first price a builder gives you is not the least he will take either. Get a break down of the costs and PM it to me, i will let you know where he is overcharging.
• Have to say I disagree with rictus123 too - it is a lot of work, but it is nowhere near Ј55k of work! However, his advice to get more quotes is very sound... seek out some local recommendations. If you can't find any, then have a look down your street/local area for people who've had extensions done and ask them if they'd recommend anyone.
• I had the whole of the rear of the house extended out 3m with one part a double extension to extend a bedroom. I paid Ј32052 for the fully plastered shell which included french doors and internal door in the dining extension, rear door, window and side window to the kitchen extension, and new window in the bedroom extension. I'm in Yorkshire which is probably cheaper than down south (if that's where you're based). I'd definately ask around and get more quotes.
  (We also had a rewire of the whole house and new boiler and central heating to all rooms which bumped the price up around another Ј7k)
• I can't believe people pay these prices!
  We have recently had an extension done 3m out x 5.5m wide. We managed it ourself (not difficult once you have a plan drawn up) and paid:
  1. Ј1000 for building regs plan, inspections & certificate
  2. Ј2800 for groundwork & footings up to Damp
  3. Ј1300 for bricking
  4. Ј700 for roof timber & fascias
  5. Ј1640 for roof to be tiled & 2 large velux windows & insulated inside
  6. Ј230 for 2 x 3m steel beams
  7. Ј500 for internal (previously external) wall to be knocked out to create 1 large room
  8. Ј500 2 new doorways created, 2 original doorways bricked up & chimney knocked out
  9. Ј700 for 3 x 5.5 extension to be plastered plus our original 3 x 4m room to be plastered
  10. Ј300 for a new internal door & a new external door
  11. Ј2000 for 3m bifold doors
  12. Ј350 for 2 radiators to be fitted
  13. Not sure on electrics for this room as we had whole house rewired overall cost Ј2000
  14. Ј300 for 2 large skips
  That is for all materials & labour above. Obviously you need to add on paint, flooring, kitchen but you said this was separate.
  We also considered underfloor heating - were quoted Ј700 for the materials and Ј350 to fit it, but friends have it and still needed rads too so we were put off - had 2 powerful rads instead & really glad as room is warm from sunlight through glass & cooking etc.
  PM if you need any help. I know it seems daunting but once you get into the swing of it
  Hope that helps.
  Forgot to say, we had various quotes ranging from Ј25k-Ј50k+!!
  We budgeted Ј1000 per sqm in the end which was about right :-) And that was with expensive bifolds at Ј2000.
• no wonder tradesmen are out of work when they are charging this much, i think they must be charging for a years work and at that price i dont think theyll be getting much.
  Im going to have a extension hopefully this year, im going to get my plans drawn up and then go from there, i know plenty of builders who would be gratefull for the work and they dont charge stupid prices.
• Thanks for all your comments. It is interesting to hear what others have paid.
  For sure, there is no way we are willing or able to pay 55k! We had another builder round who will be quoting. He has done work locally and comes recommended. We are keeping our fingers crossed that he is more reasonable.
• I was recently in someones nice semi which they had bought a few years previously.
  There was a wide crack in the solid floor and the extension was gradually parting company from the house due to rubbish foundations.
  I guess its worrying finding a good builder.
• Yep, totally Agee that your builder is having a laugh. Always get at least three quotes and make sure you thoroughly check out the credentials of the builder you choose before committing.
• Have found this interesting as we are planning a 2 storey extension in the near future and am worried about the cost I think it's 23 sqm and we hoping to do it for 35k
• That's a HUGE amount of money, I don't mind people earning but even to me that sounds crazy.
  I finally bought myself a house last year which had a really old extension on it, which I wanted to replace. Got the usual quotes, cheapest was Ј40,000 or the like.
  Ended up getting the plans done, and basically managed the job myself, organising casual labourers as and when needed, groundworkers, bricklayers, roofers plasterers etc.
  Did some work myself, very little, but worked out quite well. Ended up going on for 9 weeks, 3 more than usual but that was due to my own stupidness. Cost-wise, it was a 5m x 4m extension, normal brick and block with insulation and a flat felt roof, kitchen and bathroom, boiler moved from upstairs into the kitchen, and new drainage at the back of the house all for around Ј26,000.
  Having said that, I went a bit crazy on the kitchen (bespoke) and granite tiles and all that lark, but could have done it within Ј20,000. IMO, if the difference is more than half, give it a go yourself or seriously shop around.
• Sorry, know this is an old thread but i have been searching to try to find out the appx current cost of a single storey rear extension. I'd be looking at 7m x 3m appx with pitched roof, 2 velux windows and 2 lots bi-fold or french doors across the back. I won't be knocking through from the existing house at all just using the existing door opening as access. I am thinking of a shell only cost to leave in a state ready for finishing (laying a floor, painting walls, skirtings etc.). I've asked the architect who is likely to be doing the drawings and he reckons Ј50-60K which seems phenominal and certainly way above my budget and expectation. I'd also like to know if it would be cheaper to get a company in the build "an extension" or individual trades for each step.
  Cheers
• Hi, was trying to post a link but failed miserably. If you search for a thread
  titled Extension single storey cost? there might be some useful info. different extension sizes etc but may give an indication.
• here's mine so far.....
  it'll be about Ј30k all finished.
  ~8m x 4.5m with 4m bifolds (with blinds)
  got separate trades but probably didn't save buckets. At least i know all of them and their work and i know how hard it can be to get a decent builder. Id expect to pay a bit
  We're inside m25. Expect to pay anything between Ј1k - Ј3k per sqm depending on location and finish.
  no structural work as such but we'll be taking out the window on the right to create an opening from the current lounge.