How to extend a 3-bed semi?

[WindUpBird]

Ideally we'd move to a 4 bed house but where I live they are just too expensive. So a 3 bed semi has come up for sale in a road we like, but it needs a lot of work, plus we'd like to extend, either over the garage (and possibly convert garage into a room), or extend the back of the ground floor to create a toilet, utility, kitchen/diner, or convert the loft to a bedroom and bathroom.

I don't really know where to start. I've contacted the council's planning dept and they have said that in theory the above suggestions may be possible, I just need to take a few pics of other houses in the road, draw some sketches of suggested extensions and meet informally with their duty officer. Obviously they can give no guarantees until we actually apply for planning permission.

How do I find out how much each of the above extensions would cost? If they're going to cost too much then it is pointless us buying the house. I've been trying to find floor plans and vague building costs online but have so far been unsuccessful, but not sure I am looking in the right places.

Do we need an architect if we were to go ahead and buy the house and extend it? Or are there standard plans I can get from somewhere to show to builders to get some quotes? Would living in a house with 2 pre-schoolers and building work going on be too much of a nightmare? I have no idea, I have always lived in 'ready-made' houses. Once I know where to start with all this we'll be able to make some decisions. Any advice at all would be grand...

This house sounds like mine.We had a rough quote of £1000 a square metre,but haven't had the money to do anything so far.I can't really help much beyond that,other than to say that when we moved in.ours was structurally sound but that was it-otherwise it hadn't been touched in over 30 years.We moved in with a 3 wk old and a 21 month old and managed ok.We had to have it rewired,new garage roof,new bathroom,new kitchen,everything really.It has been expensive and slow,but we live in a lovely area that there was no way we could otherwise afford,and the house is coming together now.
Good luck

Single storey extension is roughly £1000 per sqm as 101 says plus £1k for the roof. That is with 900 depth footings.

The garage may have be to rebuilt or underpinned depending on its foundations as it will only be single skin brickwork if there is nothing above it.

You can clearly see if anyone in the street has built over their garage and also use google maps to see if anyone has built an extension therefore meaning you are much more likely to be granted permission.

It also depends on the age of the house too as to what else you may plan to do with it.

My mum & dad are doing this. They called an architect who was happy to come out & quote for free. I went round the house with him & my mum, it was very interesting as he had all sorts of ideas for what could be done. Fwiw he said that £1000 per square metre was bare minimum & in his written quote it was £1300 and this didn't include VAT. Also bear in mind that it doesn't include theactual kitchen units etc. Going up into the loft is a lot less. The architect told my parents that it would be possible to live in the house but it would take longer, 4-6 months if they did it before they moved in, 6-8 if they moved in first. HTH

just remember with going up, that it presumably means you or kids sleepign on different floors, I wouldnt do that myself.

we have a 3 bed terraced so only option was to go up into the loft. It cost 28,000 to do that and the main bathroom as well. We had to have planning consent but not full planning permission.

Our dds are so flipping loud it doesn't matter that they are on the floor below also the dog is on the ground floor and would kick up a fuss if anyone came in and the lodger is on the kids floor so no problems really.

We have done a lot of work looking into this in a similar-sounding house so I can give you ball-parks.

• convert garage into a room: 15k
• building two-storey about garage: 60k
• extend across the back of the house (single storey): 45k
• massive conservatory across the back: 20k
• attic conversion: 25k PLUS depending on structural work needed
• off-the-shelf garden office: 10k

We aren't doing any of it as it is too expensive but we spent 2k on architect's reports and drawings to get planning permission - but at the end of the day couldn't cope with the stress/expense.

We're in the exact same position as you. We're buying a 3 bed end terraced, converting the garage to a play room and building a 4th bed above in a few years when we can afford it.

We have been quoted 8k, for the garage conversion and given a ball park figure of 1k per square meter for above the garage.

However, I think it probably varies according to where you live. I should imagine London is a lot more expensive to do than where we are in Wiltshire!

Have you checked that the garage on the side of the house can actually be built ontop off - sometimes the depth of fondations for a garage are not deep enough and you may need to knock the garage down to then build agian at correct depth of fondations for a first floor extention..

We've spoken to a builder, and are probably going to go down the padstone? pagstones? route? Not sure, but the builder is someone we trust, it is what he recommends and indeed did to his own house.

We have just come through the other end of a big conversion and extension, took most of my life away last year. My DC were 2 and 5 through most of it, and whilst we are over the moon with the result, its not to be entered into lightly, demands a strong constitution etc etc....I personally would never do it again but it has been worth it.

There's a lot of upheaval, esp if you have to move out ( remember to build in the cost of renting another property whilst still paying for your existing one ) and probably the most stress I have ever experienced. Having said that, I think without young children it wouldn't have been nearly as stressful for me personally, and am unsurprised that a lot of these serial renovators you see on Grand Designs etc don't have small children.

We lived in our house for 4 years before we had the work done. It was a dump, too small, bad layout and thoroughly depressing. But we needed that time to decide what exactly to do - you do need to live there for a bit first IME if possible before you decide, to save up and work didn't actually start until 18 months after we instructed the architect, which isn't that unusual.

Location IME counts for an awful lot. There is no way we would have been able to afford our house if we had to buy it now, renovated,IYSWIM. So, I would say if you plan staying there for a long time, do it. Otherwise, walk away.

Thank you everyone, this is all amazingly helpful advice. And great to have an idea of prices too. We have had a builder friend look at the property details, and I've also contacted the planning dept so I know the garage was added in the 60s and therefore it would need to be pulled down and rebuilt if we were to build above it.
It looks as though a loft extension may be the best option, though as QOD said, not keen on being on a different floor to the DCs as they wake frequently in the night!
Taffetacat, that is a big concern of mine. What did you have done to your house? Was it on a bigger scale than the kind I'm anticipating? DCs are nearly 4 and 2 so massive building work will be a nightmare, and we couldn't afford to live elsewhere while the work was being done.
Fizzylemonade yes, I love looking at house layouts on googleEarth. Plenty of people in the street have had plenty of different conversions, the house next door has had a loft conversion, so I guess if we did the same the houses would actually 'match' again, iyswim.
morningpaper We'd also thought of the massive conservatory across the back but I can't fathom how this works structurally. Do you remove bits of the back walls of the house too?