Building basement

[Amwantingbasement]

We are about to submit plans for a basement for a terrace in London. We will then serve party wall notices. Dig out will take 4 months but we also want to take opportunity to renovate our house, put sound proofing in, re-model upstairs. We have flip flopped for about 3 years on this because of the disruption it will cause to our neighbours but it is much more cost effective to build a basement than to move.

I think things have improved in the last 10 years and my builder said the only really awful noise is when they are breaking concrete.

For anyone who has done a basement - what was damage to NDN like? For anyone who has lived next door to someone doing a basement, how horrendous was it? We obviously wouldn’t do this during lockdown but are hoping to start in summer...

Is it making good a basement that already exists (e.g. storage) or a complete excavation?
Former colleagues lived through excavated neighbours' basements in London and not one had a positive experience. The noise is gut wrenching especially in terraces and the problems with access caused by deliveries, cranes, skips are an issue. In one case, there was damage to the direct neighbour's entire party wall.
I also have a friend who did a basement and despite assurances ended up having a pump running 24x7 because the water level was interrupted.
Sorry to sound harsh but I think excavated basements should be banned in London terraces. Why not move to the suburbs and buy a mansion for the same price with space to extend?

Has anyone else done this in your road? You could ask them if so.
Think about what's involved - it is not going to be a simple quiet job so get used to the idea of the neighbours being pissed off at you for a while - bring them gifts!!
All sorts of issues with water so make sure your background calcs and research is accurate (I expect the council will require several reports on this anyway)

How much does this sort of thing cost? Is it really cheaper than moving?

£500k all in and about £350k if we move on stamp duty and EA costs without getting any more space...maybe 100 sq ft extra...if we go for a house with more space - equivalent to what we would get with basement, you are looking at at least another £1.7m (when take into account stamp duty and moving costs). So it is significant. That’s why so many people do basements.

Yes - lots of people have done basements in our road - but probably not in last 5 years...

What was the damage to NDN like? Potentially this:

Hmm I think it will cost you more than £500k for a basement and full house remodel and refurb. We had several quotes for the same and they all came in at more like £8-900k. (Hence we ditched the basement part which was going to be about half of that.)

If you do get it all done for £500k hats off to you and please PM me your builder’s details...!

To answer your question: not my neighbours but my friend’s neighbours did a basement in 2019. I believe my friend had some minor cracking which was repaired without much bother. They also now have problems shutting some of their doors, due to slight movement. That’s more of an issue.

It was incredibly painful to live through. Took over a year. Constant noise. Their builders weren’t the most considerate either (eg chucked rubbish over the shared fence) which didn’t help.

Do not believe your builder for one second. The noise is awful even if just laying a carpet (which only takes an hour but I still got complaints!). I've renovated plenty a house (not dug a basement, but when working in one the upstairs neighbour called the council out twice, once for noise (he said it was acceptable renovation noise) and once because she said we didn't have planning (we did, and I had canvassed the whole building beforehand for their approval, she just wanted to make it as difficult as possible for us).
So you will be very unpopular for a few months, especially as many people are going to continue working from home.
I'm not saying you shouldn't do it, just do not underestimate how disruptive it will be for everyone.

Summer start is optimistic if you haven't got planning for it.

If you get planning there will be all sorts of restrictions on it too.

Basement plus whole house renovation is a lot.

We’ve done one...

There are a few different techniques they can use. We went for a company (Estbury) which goes in through the front garden to get under the house so leaves the ground floor in tact.

The noise isn’t terrible. The whir of the conveyor is mildly annoying but they are mostly digging through soil, rather than drilling through concrete.

The alternative methods take out the ground floor front window to go in, which makes the house unliveable through noise but is quicker.
So a better option if you want to move out for a while.

I would treat the refurb as a separate project. The dig will cause some minor cracking to plasterwork on ground and first floor (and to neighbouring houses) so once the basement is done, get the rest of the work done

You won’t need to soundproof the basement - it’s a massive concrete box which is inherently soundproofed.

If you want to do the upper floors, it doesn’t need to be tied in the basement work

Are you going to live there while it's done? We did and it was fine. It's the only way to really sort out problems. The people nextdoor did theirs before moving in and had no idea if the rules their builders broke and bent on noise, dust, working hours, parking, skip permits.

Have done one. Have had neighbours do one. Its no fun for anyone and is loud and vibrations reverberate through the whole terrace. What I would say is be very strict on working times... ie none before 8 or after 5, and nothing at the weekends.
Also I think 500k is too low, you will be closer to 1m than 500k for a basement and whole terrace refurb. 800k is probably about right

Having more of a think about this...

If you want to completely reconfigure the upstairs, have you thought about doing a total strip out and rebuild with a retained facade, where they literally demolish the whole house apart from the front wall.

The house then gets a new steel frame inside and then the rooms get boarded out around the frame.

Obviously you lose a lot of period features (although good builders will be able to keep them in the strip out and reinstall them) but you get the exact layout you want, staircases in the right place, and the plumbing and wiring of a new build. It also makes it super easy to do the basement, because they aren't worrying about access etc

Not sure what it costs, but I've seen enough of them around us (SW11) to assume the numbers must just about add up..!

Please don't do it...I've had builders for years on end...18 months for 1 basement build. Another just starting. Get a loan and move!