Rough idea of extension costs?
Rough idea of extension costs?
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speed8

Original Poster:

5,103 posts

295 months

Tuesday 26th January 2010
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We're looking for a house just now and there's one fairly local to us which is a little bit smaller than we wanted but could be got at a decent price and has a rather large garden to potentially build an oversize double garage in. If we went for it we would probably want to extend to the rear on the ground floor to make a new dining room and extend the kitchen, and change the old dining room into a study/playroom. Total new floor area would be about 25m2 approx.

Picture of what it is now (left) and what we would like (right). There is currently a conservatory which would have to be taken down so I haven't shown it.

Any idea on rough costs for this, not including new fixtures and fittings?

Thanks


stu67

881 posts

210 months

Tuesday 26th January 2010
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As a rough guesstimate you are looking at circa £950 per sq m for single storey build, £1100 per sq m for double Storey build. I would stress that this is your basic build cost for simple extension works going out to a single contractor, if you were to sub out to single trades you may get it a little cheaper. This cost doesn't of course include for your fitted kitchen etc where obviously the sky's the limit.

DAVE-W

544 posts

233 months

Tuesday 26th January 2010
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Yes - agree with Stu's comments above at circa £1000 per square metre for basic build cost.

mkindyblade

136 posts

202 months

Tuesday 26th January 2010
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stu67 said:
As a rough guesstimate you are looking at circa £950 per sq m for single storey build, £1100 per sq m for double Storey build. I would stress that this is your basic build cost for simple extension works going out to a single contractor, if you were to sub out to single trades you may get it a little cheaper. This cost doesn't of course include for your fitted kitchen etc where obviously the sky's the limit.
Does that price includes plaster, floor, electrics, plunbing.....etc?
Or just the building?

herbialfa

1,489 posts

224 months

Tuesday 26th January 2010
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I agree! £1000 per square metre!

Thats a plaster finish ready to paint!

stu67

881 posts

210 months

Tuesday 26th January 2010
quotequote all
mkindyblade said:
stu67 said:
As a rough guesstimate you are looking at circa £950 per sq m for single storey build, £1100 per sq m for double Storey build. I would stress that this is your basic build cost for simple extension works going out to a single contractor, if you were to sub out to single trades you may get it a little cheaper. This cost doesn't of course include for your fitted kitchen etc where obviously the sky's the limit.
Does that price includes plaster, floor, electrics, plunbing.....etc?
Or just the building?
Yes that's including plaster, concrete/board floor, basic electrical and plumbing fixtures. Doesn't include expensive finished items such as expensive designer light fittings etc.

speed8

Original Poster:

5,103 posts

295 months

Tuesday 26th January 2010
quotequote all
Cheers, that's what I figured it might be around. Up to a ready to paint finish is fine as I can do most of the other stuff myself if I need to save some costs to put elsewhere. Didn't fancy doing structural work myself, especially where planning and buildings regs are most likely to be involved. Almost makes it worth doing a double story extension for the little bit extra but I just don't think a second story would fit with this building so a single it would be.

Turbo5

594 posts

233 months

Tuesday 26th January 2010
quotequote all
My neighbour is a very good builder, he has recently completely renovated from bare brick my mothers house and also he has done quite a bit of work at our house. I am very fussy and rarely give praise to builders but he is very good and reasonably priced. You are more than welcome to come and look at some of his work if want.

Spudler

3,985 posts

218 months

Tuesday 26th January 2010
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anonymous said:
[redacted]
As you put it, "floor space". A big chunk of any build cost is in the ground, its the same whether its a single or two story, so the cost for going an extra floor doesn't reflect the cost of a single...if you get my meaning.

Rollin

6,282 posts

267 months

Tuesday 26th January 2010
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Turbo5 said:
My neighbour is a very good builder, he has recently completely renovated from bare brick my mothers house and also he has done quite a bit of work at our house. I am very fussy and rarely give praise to builders but he is very good and reasonably priced. You are more than welcome to come and look at some of his work if want.
Maybe looking for a builder myself soon. Where abouts in the North West are you? Anywhere near Mancheser?

speed8

Original Poster:

5,103 posts

295 months

Wednesday 27th January 2010
quotequote all
Spudler said:
anonymous said:
[redacted]
As you put it, "floor space". A big chunk of any build cost is in the ground, its the same whether its a single or two story, so the cost for going an extra floor doesn't reflect the cost of a single...if you get my meaning.
That's what I read it as. i.e. about 24k for a single story build or about 28k for a double story build (correct me if I'm completely wrong). If thats right and we decide to go for this one then it might be worth seeing if an architect and the planners think a double story would be do-able. Most of the houses in the area have had planning accepted over the years for various things so that would be a good sign I guess. Could get a bit expensive doing bathrooms and bedrooms along with kitchens but..... smile

stu67

881 posts

210 months

Wednesday 27th January 2010
quotequote all
speed8 said:
Spudler said:
anonymous said:
[redacted]
As you put it, "floor space". A big chunk of any build cost is in the ground, its the same whether its a single or two story, so the cost for going an extra floor doesn't reflect the cost of a single...if you get my meaning.
That's what I read it as. i.e. about 24k for a single story build or about 28k for a double story build (correct me if I'm completely wrong). If thats right and we decide to go for this one then it might be worth seeing if an architect and the planners think a double story would be do-able. Most of the houses in the area have had planning accepted over the years for various things so that would be a good sign I guess. Could get a bit expensive doing bathrooms and bedrooms along with kitchens but..... smile
Speed8 if you can get planning for a double height extension it's well worth doing over the single storey. Costs may be a bit heigher than the original basic costs I gave (eg may extend normal tiled pitch roof on 2 storey whereas use flat felt on single storey), however the pay back far outweighs this. The thing that will really add value to the house is an extra bedroom, en-suite facilities etc.
The only problem you may have is pushing it through planning if it sets a local precedent, I live in whats called a "consevation area" by the local planners and it's a strict no-no, in fact I even need permission to take down hedges etc. To push through my extension I had to include things like rain water retention and a "green roof" to get them to agree. I would of loved to put an extra bedroom on my house as it's upstairs room it really lacks

speed8

Original Poster:

5,103 posts

295 months

Wednesday 27th January 2010
quotequote all
stu67 said:
speed8 said:
Spudler said:
anonymous said:
[redacted]
As you put it, "floor space". A big chunk of any build cost is in the ground, its the same whether its a single or two story, so the cost for going an extra floor doesn't reflect the cost of a single...if you get my meaning.
That's what I read it as. i.e. about 24k for a single story build or about 28k for a double story build (correct me if I'm completely wrong). If thats right and we decide to go for this one then it might be worth seeing if an architect and the planners think a double story would be do-able. Most of the houses in the area have had planning accepted over the years for various things so that would be a good sign I guess. Could get a bit expensive doing bathrooms and bedrooms along with kitchens but..... smile
Speed8 if you can get planning for a double height extension it's well worth doing over the single storey. Costs may be a bit heigher than the original basic costs I gave (eg may extend normal tiled pitch roof on 2 storey whereas use flat felt on single storey), however the pay back far outweighs this. The thing that will really add value to the house is an extra bedroom, en-suite facilities etc.
The only problem you may have is pushing it through planning if it sets a local precedent, I live in whats called a "consevation area" by the local planners and it's a strict no-no, in fact I even need permission to take down hedges etc. To push through my extension I had to include things like rain water retention and a "green roof" to get them to agree. I would of loved to put an extra bedroom on my house as it's upstairs room it really lacks
I know about Conservation areas as I currently live in one (former coach house). My previous place was Grade II listed so I've been through that too. The one I'm thinking about is just outside the conservation area and the planners seem to be quite lenient on the applications with only one refusal in the last 30 years for all the properties round this one (I think it was quite a major extension coupled with change of use that they rejected). This place is about 75-100k below budget but that doesn't mean I'll have 75k burning a hole in my pocket so depending on the figures it might be worth it. Got to think of my garage though, wouldn't want to eat into my garage budget hehe

Si 330

1,306 posts

231 months

Wednesday 27th January 2010
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A conservation area doesn't mean you can't have a 2 storey extension. It just means what ever you propose has to meet Mr Conservation officer’s ideas. There doesn't seem to be definitive criteria, more if he likes your design you stand a good chance. The main thing they are trying to do is preserve the character and architectural style. Making sure any alterations or new builds aren’t detrimental to its surroundings. Most of the work I do is in conservation areas and it always amuses me what gets approved and ones that have issues. Only once have I had a flat refusal others have been able to sort out over a friendly chat.

silverthorn2151

6,354 posts

201 months

Wednesday 27th January 2010
quotequote all
Have to say that my experience of thise £/m2 rates suggests they are very cheap, at least in terms of London prices.

I would always allow £1750/m2 enhancing that for any complex internals or elements of work. Whilst the comments about the cost for a two storey are true it's also important to bear in mind that a 2 storey extension will almost certainly have a more complex roof that a single storey. For that reason I would tend to use the same rate for the whole floor area.

The actual site to be built on can have a dramatic affect on cost as well. Seen costs of £2500/m2 for a single storey landlocked extension. Don't forget fees as well and always build in an undisclosed contingency, i.e one you don't tell the builder about. I recomment 10-15%.

Si 330

1,306 posts

231 months

Wednesday 27th January 2010
quotequote all
For the Yorkshire region £1750per m sq where the OP is based is very high.
The extensions I'm dealing with are costing between £800 and £1200 per m sq, this is in Yorkshire.
Your 10 to 15% is good advice.

silverthorn2151

6,354 posts

201 months

Wednesday 27th January 2010
quotequote all
Always useful to know where costs and prices are at, even oop norf, lol.

Don't do residential work now but clients arealways phoning up with 'my mum wants an extension' or 'I'm buying this cottage' etc etc.

Turbo5

594 posts

233 months

Thursday 28th January 2010
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Rollin said:
Turbo5 said:
My neighbour is a very good builder, he has recently completely renovated from bare brick my mothers house and also he has done quite a bit of work at our house. I am very fussy and rarely give praise to builders but he is very good and reasonably priced. You are more than welcome to come and look at some of his work if want.
Maybe looking for a builder myself soon. Where abouts in the North West are you? Anywhere near Mancheser?
Burnley

rb5230

11,657 posts

194 months

Thursday 28th January 2010
quotequote all
silverthorn2151 said:
Have to say that my experience of thise £/m2 rates suggests they are very cheap, at least in terms of London prices.

I would always allow £1750/m2 enhancing that for any complex internals or elements of work. Whilst the comments about the cost for a two storey are true it's also important to bear in mind that a 2 storey extension will almost certainly have a more complex roof that a single storey. For that reason I would tend to use the same rate for the whole floor area.

The actual site to be built on can have a dramatic affect on cost as well. Seen costs of £2500/m2 for a single storey landlocked extension. Don't forget fees as well and always build in an undisclosed contingency, i.e one you don't tell the builder about. I recomment 10-15%.
+1, i would say that if you can get a quote for around £25k you should have their hand off, we recently did a similar sized extension for a friend at cost, and although it was a bit of an awkward job in places it was about £35k although this did include a bathroom and conservatory, the quote he got from a builders before we took on the job was £60k.

Edited by rb5230 on Thursday 28th January 20:27

andye30m3

3,496 posts

276 months

Thursday 28th January 2010
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I was discussing this with a friend who's a builder / developer and he was saying build cost on a new build house with an average spec to a high standard is coming out at around £1250 per square meter in the south based on building single houses.