Extending a 3 bed London terrace

[EmBeEmBe]

Does anyone have an idea of how much it might cost to extend a typical 1930s/ Victorian London terrace house? We are thinking of (to use estate agent speak) "opening up the back of the house", making a bigger kitchen/diner and adding a wc. One storey only.

I feel a bit clueless, we are seeing houses we like and thinking about making an offer. Do I need to take a builder with me on a second viewing? How do I find a builder? Argh!?!?!

Ooh, and the agents showing us round are saying a typical 1 bedroom + shower room loft conversion would cost around £40-50k. Is that about right?

Thanks so much!

Dont know about a ground floor extension but have had a round of quotes for a loft conversion recently, small scale 1930s semi. We are midlands.

Ensuite and a 4mx4m bedroom was quoted from 31k to 36k. With all the extras such as tiling the bathroom, bathroom suite, recessed lighting, carpets for bedroom, old and new stairs, paint for walls for hallway and bedroom curtains/blinds, not the bog standard builder's door but nicer ones for the new rooms and to change old ones, so they match etc came to an extra 8k when I did a rough calculation.

We are still deciding.

Cost for London for the loft sounds realistic.

Can't comment on the extension

Loft conversion price is accurate for London I'd say, having done two in the last decade. Our side return kitchen extension with sliding folding doors etc was about £55k 7 years ago but we had to move drainage etc so it was a huge job.

Where we are (London suburbs, average house price 3 beds approx 600-700k) the standard 3m permitted development box on back of semi/terraced 3 bed house to create kitchen diner is approx 45 - 60k depending on spec. Haven't done it myself but have looked into it.

Our loft was about 30k. we were quoted 40k for a box across the back although in the end we went two storey.

Depends so much on what finish you want and what the size is. 50-65K including fees and the new kitchen is fair for something that adds around 100 sqft to your existing kitchen. The quality of your folding doors, if you get under floor heating, how complicated the loo installation is, if you need to relocate your boiler, the ground conditions and existing sewer lines etc all have an influence. For the price I am quoting assume mid range everything.

We're spending just over £50k on a loft conversion to add a bedroom and en suite to our London terrace (Victorian). That covers a mansard build, bathroom suite, tiles, carpets, decorating and some built-in cupboards. We're going for good spec finish but not the top, top end.

Loft definitely ballpark. Ours was £35 all up, including painting, but we did not put in an ensuite.

Loft is also a good estimate.

Thanks everyone! That's really helpful information. And for my next question, how long should I expect building works like this to take? Including putting in a new kitchen, painting etc.

honestly? I'd allow a minimum of four months to do loft & side return. It's the last bits ( fitting the bathroom and kitchen, decoration and flooring) which inevitably run over even if the construction itself has been straightforward. Ours was nearer 8 months in th end, with various mishaps along the way, so build in some contingency

Our single story rear extension took 16.5 weeks in total including fitting the kitchen/decorating/fitting floor.

£30,000 to £40,000 sounds a good budget. It’s a big task for a builder so get a good one. I use Checkatrade to verify. Also put clauses in the contract with timings so they can’t run numerous jobs at the same time. You’ll need Building Reg/Planning approval too so speak to the Council.