Home extension - first timer

ldaffe

My wife and I are planning a single story rear extention across the whole of the rear of our house, 8m wide by 3m.

Its a 4 bed detached with plenty of land, the next door neighbours have already done the same but double storey so Building Regs shouldnt be a problem.

This is the first time we will have done a project like this and have no idea of costs and where we can save £. We don't have a massive budget so any money saving tips or general advice would be most welcome - have thought about doing a flat pack extension (you see them on DIY SOS all the time) as a way of saving on costs. Does anyone have any opinions or recommendations on these?

Portly_Pig

Building regs will be a problem if you don't comply with them.

KennyH1

General costs for a fully finished extension is approx. £750-£1000 per m2.
You can save money by doing some of the works yourself eg digging out footings, some minor demolitions if required etc, plus painting and laying of flooring etc etc.

What is the extension for? Are you looking at having a 'flat' roof or pitched? Pitched are more expensive but a flat one may fail in the future.

In regards to building regs not being a problem, I think you mean planning permission shouldn't be a problem as the neighbours have already done the same / similar. You will have to submit for building regs.

If you are only coming out by 3m then you shouldn't need planning permission as it is within general permitted development rights but its worth checking with your local council planning dept as permitted rights may have been withdrawn.

System

KennyH1 wrote: »

General costs for a fully finished extension is approx. £750-£1000 per m2

what area is that in? seems very cheap - normally somewhere between 1000-1500 in any area I've worked in...

the flat packs things can be ok, have used sips construction a few times recently, tbh I don't think you save anything by the end of the job, the labour costs will be cheaper but the materials will be more expensive - the only good thing is that the costs are definite once you are out the ground (but it should be like that with a decent builder too!)

KennyH1

the_r_sole wrote: »

what area is that in? seems very cheap - normally somewhere between 1000-1500 in any area I've worked in...

the flat packs things can be ok, have used sips construction a few times recently, tbh I don't think you save anything by the end of the job, the labour costs will be cheaper but the materials will be more expensive - the only good thing is that the costs are definite once you are out the ground (but it should be like that with a decent builder too!)

I work at an Architects in the Midlands and we base quotes on £1500-£1000/m2 for high spec jobs such as NHS etc and then £750-£1000 for housing. That's fully finished.

markdavey

I recently had an almost identical extension done in Bedfordshire with a pitched roof, including all electrics for a new kitchen and all plumbing/suite for a new d/stairs cloakroom and doors/skirting/plastering etc. came in at £24.5k + VAT

That included 3 velux roof windows, a back door, set of french doors and 2 windows.

ldaffe

Thanks for your input guys. Yes I did mean Planning Permission.

We live in the North West (South Manchester). Planning on having a pitched roof with two skylight/velux windows with either 1 large central sliding door with a smaller window either side or one window and smaller sliding door.

At the rerar of the house currently is the Kitchen to the left and the dining room to the right. We want to make it open plan so will need a large RSG.

Flat pack is a wild card suggestion really motivated purely by cost.

gavinh1175

KennyH1 wrote: »

General costs for a fully finished extension is approx. £750-£1000 per m2.
You can save money by doing some of the works yourself eg digging out footings, some minor demolitions if required etc, plus painting and laying of flooring etc etc.

What is the extension for? Are you looking at having a 'flat' roof or pitched? Pitched are more expensive but a flat one may fail in the future.

In regards to building regs not being a problem, I think you mean planning permission shouldn't be a problem as the neighbours have already done the same / similar. You will have to submit for building regs.

If you are only coming out by 3m then you shouldn't need planning permission as it is within general permitted development rights but its worth checking with your local council planning dept as permitted rights may have been withdrawn.

We are currently having plans drawn up for an extension. Building Control said we could extend the rear elevation by 4m for a detached house (3m for semi-detached).

System

gavinh1175 wrote: »

We are currently having plans drawn up for an extension. Building Control said we could extend the rear elevation by 4m for a detached house (3m for semi-detached).

you of course mean the planning department, not building control - a read of the sticky thread at the top of the forum section will clear up the different roles of each department if you are interested op

gavinh1175

the_r_sole wrote: »

you of course mean the planning department, not building control - a read of the sticky thread at the top of the forum section will clear up the different roles of each department if you are interested op

Building Control said we could build up to these sizes without having to obtain planning permission.

Maquarius

yes it is 4m for detached and 3m for semi. Building control sometimes will advise but it is Planning you need or not need.
Your 3m should not need planning unless you are in a conservation area or have already extended previously.

Flat pack can work but you normally pay more for the materials but then save in construction time.
The cheapest is if you do part of the work yourself or otherwise manage the different disciplines yourself, i.e. get a groundworker in do dig out & do the foundations, get a bricky in to brick up etc.. This is a longer process but will save quite a bit in the end.