extension options / prices

16 Jun 2013
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United Kingdom
We are thinking of buying a traditional terrace property.

We would like to extend the width of the kitchen out into the side return and knock the back wall down to open plan the kitchen and back room. We want to have full width / height patio doors onto the courtyard and the new extension to have a glass roof

The extension size would be about 9ft x 16ft

What sort of extension would be best / cheapest?
traditional / SIPS / timber frame or a bog standard conservatory?

Currently the kitchen roof is flat so we would like to use SIPs or similar to build another room ontop and move the bathroom upstairs. This would be around 7ft x 10ft
Any ideas as to cost?

we are just looking at the basic build costs - not the finished thing

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Finished, £1000 per square metre if doing it yourself, £2500 if going turnkey with a full service contractor, or somewhere in between.

Not really sure what you mean by "basic build costs" as I'm sure your idea of something "basically built" is different to mine. Generally I find the cost of installing materials is somewhere between 1 and 2 times the price of the materials. That should ballpark you if you're prepared to quantity survey your scheme.

Get quotes from the people who will do the work? Buy a copy of SPONS if you want to get better ideas of specific prices. Try not to see 150 quid for a book as expensive; it should be able to recoup that easily, and it's a drop in the ocean of the project you're contemplating
Buy a copy of SPONS

Lol. And you think that someone with no experience will understand how to use the figures?

And the fact that those prices have no relation to reality, is going to help the OP no end I'm sure. :rolleyes:

To the OP, there are significant planning technical and structural issues with that type of work to that type of property. This makes the normal per m2 estimates unreliable
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Buy a copy of SPONS

Lol. And you think that someone with no experience will understand how to use the figures?

Gives em one eye in the kingdom of the blind.. The prices are compiled from actual work carried out so they should be a reasonable ballpark. I don't believe I ever claimed that it would allow pricing the job with penny accuracy, but equally I don't disagree with your points - OP will have to get on a steep learning curve.

Tiggy's currently in a position where s/he doesn't even own the property, so going into a fully planned extension scheme isn't something that should be on the drawing board (pardon the pun) yet; but if the question is "can it be afforded and will it be worth it?" then something like SPONS would be a helpful pointer towards getting an idea. Every project needs a budget lest it run riot with the finances

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