Two Storey Extension Cost

[LookingOptimistic]

Found architect to draw plans, however want to know approx. build cost (reall rough guide as understand it depends on many factors) before agreeing to get plans drawn up.

Now thinking may as well go two storey, plot of rear extension is just 7 sqm, so to extend bedroom directly above is just another 7sqm on top floor.

EA who valued house said the kitchen ext wont add much value if anything but two storey would as it will make bedroom above a decent size double.

Anyone done similar 2 storey extension project and can say what there build cost was? Also what was the difference between what you were quoted and what final total was?

Excluding kitchen or bathroom cists, just want to know what it would be to get built with all services in, lights, plumbibg, sockets all ready for floor/tiling/decorating and kitchen fit.

Have a look at this - they suggest it can be up to £1,600 per square metre for a premium two storey extension.

www.velux.co.uk/projects/extensions/budgeting

I was going to say the same price actually, can depend on where you live though as some areas are more expensive

Also that extension doesn't sound very big so it may cost more, or builders wouldn't be interested so get different quotes and also check their previous work

We did a 2 storey extension about 4 years ago now and worked out roughly £2k per sqm plus VAT. That's for the basic structure to a plastered finish with electrics / heating, windows etc. Flooring/decorating/internal fittings like kitchen & bathroom etc - plus the cost of drawings / planning fees etc - all on top of that. So I'd budget £28k plus VAT and then whatever you want inside. We're in the NW.

@TwoLeftSocksWithHoles

Thanks very much for this.

I have read so many articles that range anywhere from 1,000 per sqm to £2,000+ and its so hard to determine the cost for a small project. Examples always state 15sqm as small but ours will be half of that.

I keep reading where just at foundations stage people are having to fork out 7 to 10k more unexpectantly, and at this size project would kill it even with a 15% contingency.

The estimates on their look quite conservative. I don't think many purple are having single story extensions built for 1k per m2 anymore unless they are building it with their own fair hands. 2k + Vat is more commonly quoted.

You may find an extension covering 7sqm ends up costing more. Some of the costs will be fixed or not change that much depending on size. A window is a window and will cost what it costs, irrespective of room size.

@Africa2go

That sounds ok, we are South West i believe but right on border to South East so could be lumped in with trades considering us London & South East expensive prices.

People not purple

@nomdeguerrrr

We are retaining existing windows/ radiators. There are no awkward pipes or drain issues to work round.

I have read that smaller extensions can cost more, as we just wouldnt benefit from economies of scale that larger projects get.

Examples always state 15sqm as small but ours will be half of that

If you go double storey OP, your extension is classed as 14sqm as its 7sqm on both floors. The quotes you see banded about (price per sqm) are not based on the footprint, but how many sqm you're adding to the property, in your case 28sqm.

Foundations can be different costs depending on how deep they need to be, ours needed to be 2 metres deep,- friend down the road, though, much different house, Hers a Victorian semi needed 6 metres deep

I'm struggling with your dimensions - is it literally 7.5 square metres so 3.25 on each level?

We're doing one at the moment. All in its likely to come to £200,000!

But that is with all fees, fixtures, fittings and a few structural issues along the way

@Africa2go

Well it would be 14sqm in that respect 7 up and 7 down. I read other sites say to only at 50% of ground floor costs to upstairs because you would have to havw foundations (albeit deeper ones) and a roof either way. Is that all rubbish do you think?

@custardbear

Footprint is 3.5 x 2m = 7sqm. If two storey thats 14sqm as it would be exact same size upstairs as downstairs.

@Twizbe

Thats one hell of a project, i guess structual issuea can really add.

For such a small job you will be looking at over 2k /m2
That is if you can find anyone to do it... getting a main contractor in for small jobs is cost prohibitive because they don't like to do them

@Alexalee

Oh that is unfortunate, its only that bit of space i wanted. Anything more and it would encroch on garden, so will lesson value by reducing garden size.

Could you project manage the separate trades yourself?

@Alexalee

I exoect i could yes, already done a fair bit of work to house requiring builder/ plumber/ electrician. Changed all flooring/ windows & doors external and internal/ had door knocked through to garage amd tiling plus we decorated ourselves.

I know those things are quite different to building walls. Do you think it would save much in costs to project manage myself?

Yes it will save costs
And will be easier to get small firms in to do their portion of works
Ie it will be more likely to get a groundwork company in to do their 2/3 days of work
And then employ the bricklayer
You will probably find that these tradesmen can also recommend someone to do other part of your build

Single storey cost £1200/sqm not including the kitchen.

@Alexalee

That sounds like a good idea, i can easily get small trades in and expect my builder/ plumber/ electrician may all know some.

Think just need to put a lot of time into planning and arranging quotes once i have drawings and been granted planning permission. Then ensure i can arrange for these traders to try and keep to a structured timescale for each part of the works.