Neighbour's extension & party wall stuff - how do I know how deep my own foundations are?

[WireFan]

We're in a semi. Single storey extension was already done when we bought our house years ago. Next door neighbours whose house joins to ours has started work on a single storey extension of the same size. Says it's permitted development and no planning permission needed. No party wall agreement has been made as they say not needed as work is entirely on their property. But from reading a party wall agreement is needed if a) excavation is within 3m of your neighbour's property (it definitely is! Right up to the wall of our extension) and b) if excavation is digging deeper than the neighbour's foundations. The second part is where I'm stuck as I have no idea how deep the foundations on our extension are. How would I find out? Next door have dug to varying depths, the deepest being approx 4-4.5ft in places including right next to our extension wall.

We had just a few days notice of the work starting and asked about any party wall paperwork at the time and the said their builder had said it's not needed. We've not seen plans just been given a vague verbal description of the work.

But I feel very uneasy with what I've read about party wall stuff on here since! What can I do at this point since work has started and crucially how can I find out how deep my own extension's foundations are to know whether the 3m party wall act stuff applies?

Is @steveway1 around please as I've seen they've been helpful previously. Cheers!

They do need a party wall agreement and I would speak to them today! In theory you could halt their work (try not to). Go round, be pleasant but firm and say you’ll appoint a surveyor next week so as not to delay the build (they have to pay).

I don't believe this can come under permitted development, they need planning permission. I would ask them to stop until you've checked this out and have a party wall agreement and contact the council. You will need a party wall agreement to protect your property.

It could be permitted development if they don’t have any extension at all. Check the planning web site. Planning Portal will have info.

Contact a surveyor. Immediately. Ask them to survey your property and insist there is a party wall agreement. It’s vital. It should be your neighbour drawing it up. Not you. It’s there to protect your property and yes, it is required. Ask the surveyor what to do in the event of their not being one. I would contact a solicitor too if it was me.

Take photos of everything. Trial pits determine foundation depth.

Thanks everyone. I really need to know how deep the foundations of my own extension are to know whether the with 3m rule of the party wall act applies but I dont know how to find out.

I'll call building control at the council for advice tomorrow I think and will try to find a party wall surveyor.

When was your extension built?

@SwedishEdith in approx 2010.

Umm! Did a trial pit next to them!!!

@PresentingPercy sorry , I am utterly clueless on this! You mean I personally should dig a trial pit (what is that?) next to my own foundations (how do identify these?)

Usually, I'd say it's highly unlikely their foundations will be lower than yours so wouldn't be worried at all. But 4.5 foot seems quite deep as usually 1 metre. Can you look on your local planning portal for your house to see if there's anything on there? Yours may also have needed to be that deep.

I'm no expert but I find it very hard to believe they don't need planning permission.

I would contact your council ASAP. Surely if nothing else, the council should be involved to ensure it has correct building regs as it's being built?

Keep us updated OP

They're talking rubbish and you don't need to worry about your depth of foundations - whatever they are the PW agreement is required.

Our extension didn't need planning permission and there's nothing for our address on the LA planning portal. Their extension does seem to be of the size which falls within permitted development locally.

The Party Wall Act says agreement only needed if excavation within 3m of neighbouring property AND deeper than their foundations. Which is all well and clear but if you don't know the depth of your foundations it isn't so straightforward.

The builders haven't been on site for about 3 weeks now and work seems on hold but the trench they've dug has just been left open which is also worrying me.

The lack of any party wall process adds to my general nervousness about the competence or otherwise of the builders being used.

I don't know why people have brought up planning permission - it's totally irrelevant and almost certainly unrequired here.

Building control WILL need to be involved though.

None of this affects the Party Wall requirements - I don't know who said they had to be going deeper than your foundations - totally irrelevant. I think you're confusing the extension building with pure excavations. It's a different rule.

www.fmb.org.uk/find-a-builder/ultimate-guides-to-home-renovation/party-wall-agreements-what-you-need-to-know.html#when

NB for your piece of mind - if anything goes wrong, they're still liable.

The courts tend to take a poor view of failure to serve a party wall notice and you may be ordered to pay for repairs which, in reality, may not be your responsibility.

In short, the PW agreement is more for their benefit than yours!

You need a PWA as they are digging close to the party/shared wall of your semi.

Look on the government planning portal but also speak to the local planning department tomorrow as you have said you intend to do. The building inspector should come out to inspect the foundations someone soon.

Take photos of the party wall and of your single storey extension today to document the lack of cracks, just in case their building work causes any damage. They could claim the cracks were there before so it's good to have proof that your walls are currently in good condition.

Your foundation depth is besides the point. They need to draw up a PWA.

You should dispute it. You then appoint your own surveyor. Your surveyor works for you but they pay. It’s in your interests to have one so any damage is recorded and your rights are protected. It’s important to get this sorted out.

Steve the Party wall Surveyor here. The reality is you won't know the depth of your footings but you can take an educated guess from the age of the house - 1930s perhaps 600mm, 70s, perhaps 1000mm and later perhaps deeper. But if they have excavated 5'00 so about 1500mm my guess is that you should have a notice. But it can't be retrospective, it's very much going to depend on how deep they dug how close, whether it's a foundation or retaining wall and whether they were parallel to your footings if it's worth making waves over.

It’s definite there should be a PWA. It’s within 3m of her house!

If they had dug the footings out , got the building inspector out same or next day then poured the concrete I think that would have been a lot better. Leaving them open to cave in and fill up with water is just making more work for themselves. They should have served a party wall notice , but it all depends on how well you get on with them and how well you want to continue to get on with them if you do take it further and put a halt on them building ?

Some neighbours bear a grudge for a long time over the smallest of things and sometimes it’s not worth the hassle of rattling the cage .

Good luck with whatever you decide to do 🤞🏼

@PresentingPercy

It’s definite there should be a PWA. It’s within 3m of her house!

Its not, only if the excavations are deeper than the bottom of the foundations of the neighbouring property. If they are shallower or the same then the Party Wall Act does not apply. (Unless actually working on a party structure or on the line of junction).

It sounds like they are building a wall next to yours. Are they cutting into the wall for any connections? Are they going to weather the junction between the two walls or leave a gap? It's difficult but not impossible to do this sort of work and avoid the PW Act. Most people who do that successfully have taken advice from a surveyor rather than relied on a nod from their builder (all due respect to the many good builders out there, the PW Act can be a minefield for the unwary).

Leaving excavations open is just plain bad practice.

Blitz your place with photos now to bookmark condition and protect yourself (I mean every inch).

Contact a local PW surveyor, send them some views of your place and what you can see of theirs and ask for an opinion.

Might well be outside of the PW Act but it's not a good start.