Massive ground floor leak. How much damage under floors?

[PaperDoves]

Yesterday I discovered the waste pipe under our kitchen sink had come unplugged... for who knows how long. It wasn't obvious because there are cut outs for pipes on the cabinet floor where the water was draining, and additional cut outs in the subfloor. So water has been pouring at an unknown rate under the subfloor.

This is the ground floor of a 1940s home. Under the subfloor we'll have the floor joists, then a gap above the foundation I expect. How much damage can be caused by water pooling on the foundation?

Basically trying to figure out how screwed I am, and what I need to do in terms of hiring people to figure it out. If they had to rip up the subfloor under our sink it will involve a lot of redoing the floors, and that alone will be so much money.

I'm already past the stage of wanting to cry, so any advice or wisdom would be greatly appreciated.

Do you have buildings insurance???

If you have escape of water cover on your home insurance, just start a claim on that. It could be a really massive job - dh has dealt with a lot of 'things draining into spaces' claims and because you don't see the water the whole walls can have soaked it up

Yes, definitely have buildings insurance. I'm just not sure if we're at that point yet. The leak was at the back of a concrete foundation and brick wall extension and I guess I'm trying to figure out if there's a way to tell the extent of possible damage before we rip things up. Or should I just phone a builder and get the ball rolling?

You are at that point - insurance will not be impressed if you get started without their approval….

How did you notice this? Is it leaking in the sink cabinet, or under the floor?

It was leaking in the sink cabinet and I noticed the cabinet floor was damp and getting soggy (mdf). Husband seems to think it wasn't leaking for that long, but I'm not so sure. Subfloor (plywood) is evenly damp but seems undamaged.

I phoned the insurance and he wasn't particularly helpful. Gave me the verbal equivalent of a shrug and said I'd need to figure out who to call to determine whether there's any damage, and said he wouldn't record the call in case I decide there's no damage to investigate.

I don't know if there's any further damage, I just want to find out (and hopefully in a way that doesn't mean ripping up all the floors!).

If the plywood is undamaged it’s very unlikely that anything underneath it is damaged. I think your DH is right, that sounds like a fairly recent leak and mostly absorbed by the cupboard.

I suspect your biggest problem is a soggy cabinet.

Amazing, thank you for the hope! (Not that I don't like to believe my husband but, well, he's even less handy than I am haha).

Since no one else knew what to do I just spent half an hour drying the subflooring with a hair dryer, and I could literally watch it change colour as it dried (which was very satisfying) so I'm also inclined to think the damage isn't that bad. And if the screws in the floor indicate the location of the joists then I don't think they'll have any damage, either, because they're well away from the worst of it.

I also remembered when we had a slow leak upstairs that caused damp in the brick wall. I got a damp guy out and he said there was nothing to do but let it dry (and that it would take about a year), and that the brick would be fine. Five years later we still don't have any issues with that wall so I guess I shouldn't be too worried about this either (?) at this point anyway!

Thanks all!