Advice on 2 storey extension costs

Hi,

Not posted on here before but have been using the site over the past few months as there seems to be an answer for all my DIYing needs! Has been very useful.

We bought a 1890's end of terrace property last summer in Thames Ditton. The property needed work and has scope to expand. Its currently set out as follows; front reception, dining room with stairs off, 1 storey 1960's kitchen extension with downstairs bathroom and utility area, upstairs 2 bedrooms.

The property is one of 3 which were converted from a victorian villa in the 20's. We all have 1 storey extensions to the rear which house kitchen/bathrooms. We would all like to start again and and build a 2 storey extension full width across the back and further back than we are at the mo, this would involve extending the roof full width back as well.
We ideally want to make our house a 3 bed with bathroom upstairs, wc downstairs, open plan kitchen dining area opening out onto back garden. I would prefer us to build most of it in red brick to match existing and would want to make it look like it should be there rather than an ugly addition to the property.

Any ideas on costs for the build, I would ideally want everything done to 1st fix stage and I would finish the decoration, joinery and kitchen and bathroom fitting.

Sorry I've not provided any dimensions as yet, need to measure up and get some ideas on paper.

Anybody done anything similar for a client or planning this themselves?

Jonny

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lynda, moderator

please note forum rule 9

Sorry to be abrupt, but if you have been reading for a while, you should have noticed that requests for costs are either edited out by the mods, or you get a reply like "get some local quotes"

But use £1100 per m2 as a guide for your area

Jonny

I've worked around your area and I think you should look at £1200-£1500 per m2. A good builder will probably look for more. There's plenty of work in the London area at the moment, that keeps the prices up.

You can get get cheaper prices but you may not get the best quality with it. There's a few dodgy builders around at the moment, you should think about using a JCT minor works contract. It may cost you a bit more but you'll be better covered.

Another tip, if you are asked for money up front for materials, be a bit wary.

Jonny
How far do you intend to extend back as you will find planning only allow a measly 3.6m max even if your rear garden is 100m long.
Pete

Or the m3 rate at £600.

How does a m3 rate work out less than a m2 rate?

^woody^ said:

How does a m3 rate work out less than a m2 rate?

Click to expand...

3mx3m=9m2 x1500=£13500

3mx3mx2.4m=21.6m3 x600=£12960

Dunno if the rates are correct but is that not what is meant. Pretty similar for an approximation.

Thanks guys for the advice, one quick question though, what would i expect to have done based on £1000-1500 per m2, would that include specified windows, doors, new roof and everthing to 1st or 2nd fix?

Or is the rough quote just to build to 1st fix stage with walls plastered?

The exsiting 1 storey extension is 19.3 m2, I am looking to replace that with 2 storeys with approx 22.5 m2 per floor giving a total new bulid area of 45 m2.

The exisitng part of the house that is original is 67.3 m2 plus the 60's extension of 19.3 giving current size of 86.6 m2. The ideal size resulting from doing a 2 storey extension would be 112 m2.

My neighbours want to do the same so this could cut some of the build cost down I guess as well.

Thanks in advance for comments, Jonny.

On my earlier posting, £1200 -1500 m2 should get you shell, roof, windows, doors etc. which is all you are looking for. Materials would be typical contractors supply. Anything fancy or out of the ordinary would cost more. For example the electrical fittings would be white plastic, if you wanted a brass finish it would be more.

Things like bathroom goods, kitchens, tiles and such are normally supplied by the client, unless agreed in the specs. But you intend to do this yourselve anyway.

The cost of demolition will need to be added, but if you also have your neighbours involved that should help with the cost. There may well be other costs, each job is different, but hopefully given you something to work with.