Building costs guidelines

[chris French]

Ok another house buying related Q, I thought I could have Googled up the answer but no go.

A couple of houses have had potential, but don't 'tick all the boxes' in terms of rooms/space . Which has got us wondering about buying with a view to extending if we found the right property - say extending a kitchen and adding another bedroom sort of thing.

Never had to have any building work done, I've no idea really of the costs of such things (ok an extension is going to cost thousands but how many?). Now I realise that costs vary greatly depending on location, standard of finish, fittings etc. but there surely are some guide figures around of say costs per Sqm or whatever for house building works.

All I'm looking for is enough of a figure to be able to cost it into the house buying budget, any suggestions, or even just some rough costs of extensions people have had built?

[Neil Jones]

£1000/m^2 is what I've been told in numerous places, by numerous people.

[jim_in_sussex]

snip

Is that per m sq ground plan area, or internal floor area including upstairs & downstairs?

[dg]

There are two ways to deal with these approximate costs. One is to use a figure of say £700 m2 for a single storey and £1000 m2 for a double, the other is to use a figure of say £600 m2 and add together areas of both ground and subsequent floor. Its important to know which figure you have been given.

In each case, these are normally based on external 'footprint' on the ground.

In either case, one should not give too much credence to any such calculation or to those who band these figures about, as they are wildly inaccurate for cost estimating purposes. A minor alteration to some measurements or internal fit out, can greatly effect the £ m2 price, and local rates can vary too.

The only time to trust such figures is if a local builder has built similar extensions and has worked out an average build cost for that particular area.

So the only figures that should be obtained is a rough estimate from local builders based on "... how much for a two storey side extension with pitched roof" etc. Such estimates will normally be to the nearest £5000

If you are working to a tight budget, m2 approximations should be avoided

dg

[chris French]

In message , dg writes

We aren't at the stage of tight budgets yet, to the nearest 5 grand would be more than precise enough for my purposes :-) In fact the nearest 10 is more than good enough.

Just looking for a rough way to judge where to put or max purchase price if we were to allow for building an extension

[Dean]

We are in the process of having an extension built at the moment. 2 new bedrooms and a new bathroom upstairs, plus integrated garage, utility room, toilet, small store room and sun room downstairs. Basically we have doubled the size of the house. We got 3 quotes all from FMB registered builders, which all came in at about £43,000 ex vat. (This is in Chesterfield, Derbyshire).

However this is not what you will end up spending! The quotes only allocate a few hundred pounds for the new bathroom (B&Q Warehouse jobs), for example. True cost will be about £3,500 (Ambience Bain level C price band)! Also, don't forget that you will need to "tidy up" outside with some landscaping, and if you "get a little man in" (to quote mr Titchmarsh), you can figure a few more thousand, then there is the fact that the builders only quote for 1 double socket in each room and you will want two or three, etc etc. The builders we had said we ought to add on about 25% to the original quote to allow for these sort of deviations, but I will have borrowed £90,000 to do all the work, fitting and furnishing it, and to do the landscaping, so doubling would seem to be more like it.

Having said that we have spec'd the fittings quite highly, and this will include all carpets, curtains, new kitchen, new appliances new wardrobes etc etc etc.

Hope this helps.

Dean.

[chris French]

In message , Dean writes

Odd way to go about quoting - wouldn't it make n more sense to give a quote for what is actually required by the client?

[Graham Tavener]

Chris, We are currently having an extension built to add a dining room beside the kitchen at the back of the garage and a one bedroom with ensuite over the garage. We had a few quotes from £30k to £45k, in the end the lowest quote builder let us down as he kept postponing the start date from June-Oct, so we had another builder quote for £38k and they started two weeks later. We chose the current builder on a friends reference and in hindsight we should have done this before rather than choosing the cheapest. The current builders have displayed excellent quality of work and professionalism, something I know we wouldn't have received with the cheap one. They had six on site this week doing the brickwork and it has gone up very fast. The quote does not include plumbing and electrics, we are doing that ourselves, it's purely for a plastered finish. The only extra has been £900 for digging out the foundations twice as deep, on request of the buildings inspector. The house is built upon a slope and the house foundations are very deep. Hope this helps.

Graham