Extension 4m square cost

grumpy_codger

I think for "eating area" 4m2 is sufficient.

Also, a pitched roof can be problematic for a 4m extension if it's lean-to, not gable.

jj_home_80

Yeah, you're not the only one – getting builders to follow through these days can be a real mission, especially for smaller extensions. Everyone’s busy or cherry-picking jobs.

For a rough idea, a 4m² single-storey extension with a pitched roof and Velux, assuming standard spec (no fancy finishes or major groundwork), you're probably looking at around £2,500–£3,000 per square metre in Northwest Kent. So ballpark £10k–£12k for the shell, but once you factor in electrics, plastering, flooring, kitchen alterations, etc., it could easily creep up to £15k–£20k+ depending on finishes and access.

Hope that helps give you a sense of what’s fair when the quotes do eventually come in.

Section62

jj_home_80 said:

Yeah, you're not the only one – getting builders to follow through these days can be a real mission, especially for smaller extensions. Everyone’s busy or cherry-picking jobs.

For a rough idea, a 4m² single-storey extension with a pitched roof and Velux, assuming standard spec (no fancy finishes or major groundwork), you're probably looking at around £2,500–£3,000 per square metre in Northwest Kent. So ballpark £10k–£12k for the shell, but once you factor in electrics, plastering, flooring, kitchen alterations, etc., it could easily creep up to £15k–£20k+ depending on finishes and access.

Hope that helps give you a sense of what’s fair when the quotes do eventually come in.

The OP wants 16m²

grumpy_codger's point about the roof is also valid - the cost will be higher than typical if the roof is more complicated than a simple lean-to.  Builders doing quotes having sight of the plans will have a much better idea of what they are dealing with.

Bleg

I definitely do not want to lean-to. The plans are for a pitched. I will keep trying several people. I am sure there is someone out there who would respond positively and be competent enough to do the job.

Bigphil1474

The square metre average price is based more towards the 16 square metre end of build sizes than the 4 square metre end, so you are probably looking at around £50k price for first finish. I would stop referring to it as a 4m2 extension if I were you, especially if you are telling builders that. It's a 4m, square extension, which is 16m2.

casper_gutman

Bleg said:

I definitely do not want to lean-to. The plans are for a pitched. I will keep trying several people. I am sure there is someone out there who would respond positively and be competent enough to do the job.

A lean-to is a (type of) pitched roof. Do you mean that you want a duo-pitched roof with a ridge running out from the house and a gable at the far end? That'll increase the cost a bit, but is probably needed as a lean-to/monopitch roof will usually start clashing with the first floor windows if you're going out 4 metres.

Bleg

Thanks for all the input. Got a call that a rough estimate would be around 65K..Wow.... see what I mean... was not expecting!!!! that. And it does not include electrics and plumbing. Though it includes a window and french doors,rendering the outside and white paint..  This is why I was asking for other peoples experiences so I can be fair in my evaluation

Bleg

Have I stunned everyone to silence I felt like lying down in a dark room all day.

FreeBear

Bleg said:

Have I stunned everyone to silence I felt like lying down in a dark room all day.

I was going to say £3-4K per square metre. So your £65K ballpark quote isn't far off. Add a bit for budget overruns and finishing, and you'd probably be looking at around £100K.

onomatopoeia99

FreeBear said:

Bleg said:

Have I stunned everyone to silence I felt like lying down in a dark room all day.

I was going to say £3-4K per square metre. So your £65K ballpark quote isn't far off. Add a bit for budget overruns and finishing, and you'd probably be looking at around £100K.

By "a bit" you seem to mean another 50%, taking it to over £6k per square metre from £3-4k?

Is the building industry really like that?  "It will cost you X" as a quote, then the final bill comes in as X+50% for the exact thing they quoted X for?