Neighbour tanking cellar - anything to watch out for?

[tpmumtobe]

Our neighbour is having works done to her cellar so she can use it for storage. Digging down a bit, having it tanked, cutting into the wall in places. Party wall notice has been served and we have agreed to use her surveyor, they seem decent.

We have a call booked with the surveyor to talk it through but wondered if there was anything particular to be mindful of. I doubt them digging down half a foot will cause structural issues but could her lining the cellar wall on her side make ours more damp for eg? Is it likely to be horrendously noisy?

If anyone's done similar work or had neighbours do the same, pointers would be gratefully received!

Is it shared brick?

We have a tanked cellar, we had architects out yesterday to look at redoing it. It's the best way to do it, but it does mean the bricks get more wet than they otherwise would on the other side of the membrane. The cellar conversion also means there's more likelihood of damp problems from the wet bricks - we've got normal plaster rather than lime plaster upstairs and need to have that changed, as it's not letting the bricks breathe at all.

We've also got a pump in ours which would collect and remove water, so it doesn't cause any issues for next door, although she's since had hers done and I think most of the street has. But if she's not doing that, I'd want to know if it would age your bricks faster; or increase the chances of damp.

That said, if it would - there's not a huge amount of options. Declining her permission to go ahead might cause a dispute that would need to be declared on selling. Tanking your cellar too would be the obvious solution, but it'd have costs - it'd be unreasonable to expect her to pay for those in full. Maybe a contribution would be reasonable.

Do you also have a cellar? If so have it looked at for soundness, take lots of photographs and even if you have a little bit of damp there establish how much. Get neighbours to agree that they will rectify any damage to your property. If they don't want to do this you have your answer.

Ensure neighbours have a pump (not quite sure what this entails but important)

Daughter's neighbours had their cellar tanked, daughter's cellar got wet every time it rained after that. Was quoted thousands to have the issue rectified

How old are the houses and what sort of construction?

Thanks, this is useful. Victorian terrace, approx 1850s? Think walls are single brick tbh not sure. We both have small cellars that run just under the hallway, not the whole house, if that makes sense? She is end terrace, we're the next one in.

I'd be quite concerned where the moisture will go, chances are with one side tanked it will all disperse onto your side once the walls are saturated (which is what happens behind tanking).

Yes, yours is v likely to end up more damp as a result. The water has to go somewhere.

Hmm that was my concern. We have a damp meter kicking around somewhere so I might take some readings and ask that they are noted in the party wall agreement so we can compare if it does get much worse. We already use our cellar for storage and while it's not bone dry it is dry enough for most items. Will be a pain if it becomes very wet.

I will check if she's also having a pump fitted.

We had toyed with the idea of tanking ours but the cost was extortionate and we're planning other works to our house at the moment which are our priority.

Do you already have adequate ventilation in your cellar?
I don’t see how next door installing a pump helps you.

Well yes in that the "cellar" is open to the rest of the underneath of the house if that makes sense? The space under the living rooms is a crawl space about a foot high, the cellar (which is probs 5ft 2 high) runs along the side. And it's a terribly drafting old house so not exactly a well sealed space.