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Extension cost (London) is this reasonable?

(30 Posts)
ThisOneNoThatOne Thu 27-Oct-16 11:12:06

I'm just looking for some advice on the cost of a house extension. I know it'll be hard for people to answer this without seeing the plans, but I'm close to signing a contract with a building firm and I'm getting cold feet about the cost- it just seems so expensive!

We have a 1930s semi, and we're planning a double side extension, and at the back a part single and part double extension (extending by 3m at the back and 2m at the side). We're also remodelling inside and having 3 bathrooms & underfloor heating on the ground floor.

I've had 3 quotations- (£150, £180 & £210k) although with the cheaper quote it was quite basic so I think there will be lots of extras. I'm thinking of going with the £180k quotation and with extras such as flooring, kitchen I'm hoping to go no further than £215k.

Is this reasonable? I'm wondering if ive picked the wrong builders to get quotes from and have chosen expensive ones?! The builder I like is holding a slot in Feb for us but needs us to give him an answer asap.

Thank you!

namechangedtoday15 Thu 27-Oct-16 11:29:24

What exactly does that include? Is it VAT inclusive? Are you supplying your own flooring / UFH / kitchen / bathroom fittings & tiles? Does it include electrics (including sockets etc), windows / bi-folds?

ThisOneNoThatOne Thu 27-Oct-16 11:46:33

Sorry yes it includes Vat, underfloor heating system, new boiler and unvented cylinder, windows and doors- although we'll pay extra if we want something that isn't "standard".

We'll have to provide kitchens furniture, bathrooms furniture and flooring, also any unexpected things like updating electrics, upgrading plumbing etc.


TeddyBee Thu 27-Oct-16 11:52:20

It seems a bit expensive to me. We did a two storey side extension, with a two storey, dropping to one storey extension at the back (standard I think in 1930's semis!) 3m out at the side and 3 out at the back. We also converted the loft at the same time. We sorted the kitchens and bathrooms ourselves, and I sourced and ordered the doors because I"m picky. We had standard windows and finish though, and didn't have underfloor heating, although we did move the boiler which cost about £1k in itself. All in, including VAT, bathrooms, kitchen etc I think we spent £145k ish. We did have very cheap bathrooms and an Ikea kitchen and utility we we fitted ourselves. Not much tiling and we also did the floors ourselves, which clearly is a lot cheaper. But our building work was only £120k including quite a big extra spend on plumbing and rewiring the whole house, and replacing some damaged joists in the loft when converting it.

whatsthecomingoverthehill Thu 27-Oct-16 12:03:43

It really is impossible to say. People compare per sq m but when you've got internal work as well it's difficult to judge it accurately.

All you can do is try and get builders who have been recommended, get a feel for how much they want the job (expensive quotes are often if people are busy/don't like the look of it so just give a high price). Make sure you are giving them decent information to quote on.

ThisOneNoThatOne Thu 27-Oct-16 12:04:58

Thanks TeddyBee. That is a good price. I take it you're in London and how long ago was it?

Also did you project manage it yourself or did you have a main contractor?


TezzieD Thu 27-Oct-16 13:28:58

Message deleted by MNHQ. Here's a link to our Talk Guidelines.

idontlikealdi Thu 27-Oct-16 13:35:25

We have been quoted 60-70k for 3 m (permitted development) single storey extension on a victorian terrace inc everything. Had a vague quote of another £30k ish to take up to second level.

Yours sounds like a lot more building work so could be about right.

The problem we're having is they are all so busy they can pretty much charge what they want.

TeddyBee Thu 27-Oct-16 19:02:13

Outer London a couple of years ago. It was a good price, and the finish was basic, but if we'd had more money I would have got more specialist trades in to do the doors and skirtings, and had better windows. We had one main contractor who subcontracted, and did have a few problems with their standards sometimes. If we'd held onto a contingency instead of spending it on a rewire, I probably would have paid a snagging firm to come and fix those issues as it was like pulling teeth to get the main builder back on site.

ThisOneNoThatOne Thu 27-Oct-16 21:09:09

Thanks everyone. Really good to know.

johnd2 Thu 27-Oct-16 21:24:34

Wow all those sound expensive, we're in zone 4 north London and getting basically side infill 2 storey and just over 1m out the back ground floor only, including rebuilding the whole back of the roof and re tiling, also knocking down both chimneys completely and moving a load bearing internal wall plus adding a downstairs loo.
All that is just over 70k inc to a plastered finish including 3 roof windows, but we are buying and getting the main windows fitted ourselves for another 10k and doing the plumbing and electrics ourselves.
But to the op, you have done the right thing getting a few quotes from proper drawings, and if they've looked properly and are keen, then the price they quote will be the going rate. They're only going to quote high if they don't want the job. Maybe there's something expensive about your plans, but the architect should have gone through all that and found ways to fit your budget.
We had 3 within about 15% and went for the middle one. There were another 2 who were about 30% more who we didn't go for! The one we chose, we made a few adjustments to get the cost down before we signed the contract.

HollyMaingate Thu 27-Oct-16 21:48:40

Have you specced gold bars instead of bricks?

Get another 3 quotes, have a look at your local council's planning applications and see who has had similar done last year, give them a knock and see who they used and if they were happy, if so get details and a quote. To think about spending that sort of money based on 3 ott quotes would be madness.

ThisOneNoThatOne Thu 27-Oct-16 22:04:57

Yeah I know really that I need to get more quotes in. It just takes so long to get builders quotes in I'll end up losing the Feb slot that the builder has. That's why I was asking on here. I've had 6 builders round and only 3 came back with a quote!

Catanddogmake6 Thu 27-Oct-16 22:12:09

We are Surrey and although I'm terrible at guessing sizes etc have been quoted similar for what I assume is similar work. Depressing. Nor are they even keen to come and do the work. It's like they are doing you a favour if they can be bothered to turn up/ answer the phone.

coffecupempty Thu 27-Oct-16 22:28:20

I have ds called Lewis which sometimes gets shortened to Lou and
a niece called Lucia which she is most often known/called LuLu.

Lucien is a lovely name for a boy. Would shorten to Lou though, LuLu is for girls imo.

MrsNuckyThompson Thu 27-Oct-16 22:29:19

I reckon it's about right for a double height.

coffecupempty Thu 27-Oct-16 22:32:30

Oooops total wrong thread sorry blush

HollyMaingate Fri 28-Oct-16 09:22:23

Is there something really awkward about the job or site that's making 3 not bother quoting and the others so expensive?

johnd2 Fri 28-Oct-16 10:05:02

Oh yes another point is the architect looked at things like access round the back and storage foot materials, he said due the the site not being too awkward it would help with cost plus the scaffolding won't be too bad. If they have to carry everything down the road and through the house and can't store anything, or they have to work around a big family in a cramped house they would add a hassle factor on. We basically handed over the back of our house to them and said we're replacing the floor so don't worry about the damage.

ThisOneNoThatOne Fri 28-Oct-16 11:08:03

No I don't think there's anything awkward about our house or plot. It has side access and a drive. There's a lot of remodelling inside though so I expect that's pushed up the cost a bit- I wasn't expecting that much though!

I just assumed the builders that didn't quote were so busy and just forgot. Also we didn't have planning permission approved when I started looking for builders so I think that put some of them off.

johnd2 Fri 28-Oct-16 11:47:08

If possible sort out all the planning, building regs, water build over agreements and party wall stuff before they arrive, then all they have to do is start building. That way they know you are serious about starting asap.
Also if you have a good architect, the builder will know you are serious and will want to get future work through the same architect, so they won't want to mess around.

Notonthestairs Fri 28-Oct-16 16:42:13

We're doing the same extension! We live in Herts. It is been very hard to get quotes and we've got buildings regs etc sorted. I've approached four firms (all recommended and I've seen their work) - got two back one for £159 (before VAT) and for £107 (before VAT). The second quote doesn't include under floor heating or kitchen fitting or patio). Just chasing the others.

Notonthestairs Fri 28-Oct-16 16:43:56

Forgot to say my quotes include loft conversion.

ThisOneNoThatOne Fri 28-Oct-16 16:49:30


If we added a loft I think that would be another £45k onto the cost so that's very different.

Notonthestairs Fri 28-Oct-16 22:07:35

I asked them to give me a quote without the loft extension but only the first builder provided that. It went from £159k to £128k.

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