ᐅ The construction of the basement is a concern for me.

Hello everyone,

We are building on a slope, a gentle incline with the natural terrain sloping away from the house towards a dead-end street. Access/entrance is from the dead-end street into the basement (lower ground floor). Above our house, there is also a road... about 2.5 meters (8 feet) higher than our single-family home.

Now to the question: we have clay soil that does not allow water infiltration, and our basement is half exposed and used as both an entrance and living space. So only one half is underground. The basement will be constructed as a "black tank" (bituminous waterproofing system) with a drainage system to carry water away, connected to the wastewater sewer. This has been approved by the city. Since we have a separated sewage system, it is permitted.

According to the soil report, this is sufficient. However, I am still worried because a damp basement would be a nightmare for us. Therefore, I am considering not cutting corners and having a "Thepro" basement built. It is supposed to be better than a "white tank" (concrete waterproofing system) because it is secure against water penetration from the outside. This would cost us €8,000, and the general contractor says it’s definitely not necessary since most of the basement is exposed. Still, I am concerned, especially thinking about future increases in severe weather.

What do you think? Is this adequate, or should I trust my gut and play it safe?

Best regards

Hi, the inspector and the general contractor will probably be able to give you better information than we can here in the forum without knowing the exact location.

For friends of mine, for example, a waterproof concrete basin (WU shell) was definitely necessary on the slope because the infiltrating rainwater was pushing against the house. If you can intercept that with drainage, there shouldn’t really be any problems, but as I said, the inspector can provide more details.

Personally, I would be more concerned about heavy rain events, especially if it feels like a half river coming down the hill. Flood-resistant windows and doors on the uphill side would be an absolute MUST!

Best regards,

Andreas

We have a similar situation with a slope and a 40% exposed basement!

But isn't the dimpled membrane still missing?

I would trust your general contractor, especially since if something goes wrong—which is very unlikely—he has to take action and it won’t cost you anything.

Maybe you should put your concerns in writing to him, just in case.

tomtom79 schrieb:
We have a similar situation with a slope and a basement that is exposed about 40%!

But isn’t the dimpled membrane missing there?

However, I would trust your site manager, especially since if something does go wrong—which is very unlikely—he has to take action and it won’t cost you anything.

Maybe you should also put your concerns in writing, just in case.

And how did you build your basement? Yes, that’s a good tip... I will do that.

Well, insisting on the warranty during house construction (especially regarding the basement) is quite risky.

That’s not going to work...
Dimpled membrane is not intended for waterproofing and only protects the insulation. We had sandy soil, so we could do without it...