Water between basement floor and floor slab

Hello everyone,

over a year ago we bought a semi-detached house. The other half still belongs to the seller (who was also the builder and a craftsman himself) and is being rented out.

Due to the extreme rainfall last week and a clogged drain in the driveway, unfortunately our basement window well filled up and water entered the basement. It was about 3cm high in all rooms. We were able to completely remove it 3-4 hours later.

However, the walls have become damp in the lower part and still are after 1 week. It feels like it is getting worse. It looks as if the moisture has risen to knee height. The paint is already peeling off.

The strange thing is – at our neighbors, where no water had entered – the same picture appeared 2 days later. Not only on the wall facing us but everywhere.

The seller/builder has now done some test drilling through the tiles + screed + insulation layer in his basement today. Water is standing between the cover plate and insulation layer there!! (I haven’t been able to speak with him yet..., only with the tenants.)

What could have gone wrong? Is it water from our basement that has seeped down through the tile joints + screed? Is that even possible in such a short time? Could it be that the groundwater level or backed-up water (possibly from the soak pit next to the house) has risen and somehow found its way between the floor slab? We don’t have a "Weiße Wanne" or anything similar, but only a basement wall insulated with bitumen. According to the soil tests at the time, there is no groundwater in the upper 5 meters.

We are quite at a loss, frustrated, and afraid that the house will become a financial disaster for us.

Would you recommend that I engage an independent expert and even, as a precaution, a lawyer? Would the damage of any kind possibly be covered under the warranty?

Thank you very much in advance for your time, assessments, and tips.

Good evening,

first of all: stay calm, even if it is currently difficult!

Due to the extreme rainfall last week and a clogged drain in the driveway, unfortunately our basement window well flooded and water entered the basement. It stood about 3 cm high in all rooms. We were able to pump it out completely 3-4 hours later.

The walls have become damp in the lower part and still are after 1 week. It feels like it is getting worse. It looks as if the moisture has risen to knee height. The paint is already flaking off.

There can be many reasons why there is moisture in the house; guessing why and for what reason won't help you. On the contrary, the longer you ponder, the more nervous you will become! No user here – at least no one of sound mind (I hope) – will give you an assessment of where the cause "might" lie. That would be, in my opinion, irresponsible!

[*]Have you already spoken with your seller or informed him in writing with proof?
[*]Who is responsible for the clogged drain in the driveway? What caused the clog?
[*]Who owes the warranty – if it is at all the fault of a craftsman – only you can know, since you have not commented on the former construction project itself. Who built it? The seller himself with other craftsmen or did he build via a general contractor? Do guarantees or warranty retainers exist?
[*]Was the basement built according to the specifications of the soil report in the ground?
[*]Have you taken out elemental insurance and/or spoken with your insurance company? Insurers have their own experts, possibly they will send a surveyor to assess the damage.

Personally, I would only consider involving a lawyer or expert if you can find no reasonable settlement with either your former seller or your insurance. What I would definitely do, however, is set up drying devices and document the situation on site with pictures as well as in writing. It will rain again, and as long as it is unclear where the water is coming from, I would want to prevent further penetration into the building fabric; regardless of determining the cause.

Good luck and Rhenish regards