Rough cost of extension London

tostaky

Hello, 
we are looking to buy and two houses could be a possible:
House A: needs rear and side extension (and loft extension) - good location
House B: only bifolding doors and a skylight into the existing (albeit old) extension are needed (loft is done) - less good location (same area but funeral parlour on the corner of the street)

Can i have a ball park estimate for building work for side and rear extension please in North London? 

Also, do you think it is possible to add bifolding door + skylight into an existing extension even if old? Or would we need to take it down and start from scratch? 

Thanks a lot

FreeBear

£250,000 to £1,000,000 depending on size and specification.

To be honest, without some idea of size & standard of finish, any estimate of cost is going to be a finger in the air job.

Rosa_Damascena

Always go with the best location with the most improvement potential - which is property A in this case. Converting the loft will be the least expensive starting point and your location is known for home extension projects, but expect to pay a high price.

FaceHead

Dimensions and number of floors etc are essential to providing any sort of estimate. Perhaps post the floorplans with some notes of what you have in mind? 

There's then 'what do you want to include', in terms of decorating, flooring, fitting a kitchen in etc. 

£2000+VAT per msq is a rule of thumb for a plastered room with some plug sockets, but it scales with size, and is less (per internal floor area) for two storey additions. 

Yes you add a bifold door and skylight. Information on the construction, sizes, age etc. is necessary to help with whether it's a good idea or prohibitively expensive. 

tostaky

Thank you - thats useful.
im only thinking about building work atm, not fittings.

when you say £2,000 sqm do you mean the added sqm or do you take the whole floor?

Rosa_Damascena

£2k/sqm of the new floorspace created.

Doozergirl will be along in a bit and she will disabuse you of any illusions you hold about this build (as she did with me, in the nicest possible way).

Eta: I see you have added in a floorplan - property A, presumably? It leaves very little garden for the plot. You may need to scale back your ambition and I'm wondering if it will get PP? If it does then yes you are looking at a reconfigured space of around 30' x 15', around £150k min.

Eta #2: making the existing cellar habitable might be less expensive?

tostaky

Rosa_Damascena said:

£2k/sqm of the new floorspace created.

Doozergirl will be along in a bit and she will disabuse you of any illusions you hold about this build (as she did with me, in the nicest possible way).

😂😂 in a way that is exactly what i am looking for! 

tostaky

@Rosa_Damascena I am not worried about PP as many houses have done this in the same street.
None have done the basement (Ive looked through the planning permissions database for the last 5 years)

and yes i would like a bit more garden but I am worried than having a slightly shorter extension might cost even more than just leaving it as it is!

stuart45

tostaky said:

when you say £2,000 sqm do you mean the added sqm or do you take the whole floor?

I guess you are asking if the price per metre means if that is for a single storey extension, does it double as you are adding double the area.
It's generally more cost effective per metre for the second storey as the foundations are already in place and a roof is needed anyway. The extra cost is the floor, walls, ceiling and scaff, but you are getting another storey.
For the bricklayers the second floor is more work, so in the past some of them used to draw up the cash and clear off to another job once up to joist high.
I would have thought in the London area you would be looking at 2-3 grand for a single storey extension, but prices vary if a special foundation is needed, or access is difficult. Even working in a busy street with no parking makes things more tricky.
With the door question, they should be possible. An SE sometimes want a steel goal post system in certain cases.

GDB2222

Why is an undertaker on the corner a bad thing? Could be worse. At least, they won't be noisy.

Rosa_Damascena

GDB2222 said:

Why is an undertaker on the corner a bad thing? Could be worse. At least, they won't be noisy.

In real life this won't bother the OP a single bit. Its one of those things that put inexperienced buyers off (it would have me as a FTB).