Extension cost idea please

Hoploz

We are planning to do a large extension on the back of our house, but have absolutely no idea how much we should expect it to cost! I realise once we get an architect in they will be able to give costings etc, but I need to know whether we are likely to be able to afford the plans we have in our head, or whether we need to think again before we get into professionals' fees etc.

We plan to go full width (approx 24') and full height (two storeys) hopefully about 12' deep.

Downstairs we'd have a kitchen and sitting room overlooking the garden, upstairs would give a generous master bedroom suite consisting of bedroom, ensuite and dressing room.

Can anyone give a suggested cost, however vague? Thanks.

ormus

cost really depends on where you live?
another thing is that most councils wont allow more than 25% increase in the property area sq footage. your plan seems rather large?
also which sort of roof you want? flat roof is much cheaper.

rough budget cost can as low as say 20k here in the NW. poss 100k in the SE.

Hoploz

We are in Surrey.

We are hoping for 12' deep but 10' would do at a pinch. Most houses in our road have done 2 storeys half way across (still morethan 25%) but due to light we think it'd be better to go right across. We are the only house in the road with no extension done at all. I will be going to council to discuss probability of acceptance in the next day or so.

We would prefer pitched roof.

ormus

we have a friend in staines, (semi detached house).
hes just had a quote of 80/100k!!! for a 2 storey extension.

amd

At the moment a rough 'ball-park' figure to work with is around £1,000 per square metre. (This varies up and down the country) That's total floor area, adding both floor level areas together, using standard construction and employing a builder to do the lot. The architect should be able to draw something up to your budget. However, prices are only increasing so allow a good 10% contingency on top and get at least 3 quotes.

Could be cheaper if you feel confident enough to use your own sub-contractors - but you'd need to know what you were doing though. For something of the size you're thinking of, if you're a first timer I'd stick with a main builder, perhaps getting the architect to oversee the project - for yet another fee!

brightontraveller

If other houses in your road are of same design. Construction etc as yours you can go to local council or look them up online and get copies of the plans submitted for there’s as they have already been granted permission a president has all ready been set so planning should be no problem, also there plans with a few changes e.g. there address etc can be submitted saving hundreds on drawings etc most if not all the calculations with regard timber sizes, lintels, roof etc will be on there if like most roads all the houses are the same if you get on with the neighbour who has the extension you can also see what the finished will look like and if there are bits they would have changed ?