ᐅ Seepage Water Buildup in the Basement – What to Do?

Hello everyone,

we are planning to buy a property and have noticed that seepage water keeps rising in the basement. Apparently, there is a clay layer beneath the ground that prevents the water from draining away.

Does anyone have experience with this issue and can offer advice? We would like to use the basement and keep it dry.

Best regards
memoc

Welcome to the forum,
we have similar conditions in the building area, and my first thought is drainage.
Talk to your neighbors; they have the same soil and the same problems, and you will learn which measures have been effective and helpful.

Welcome to my world. A 100-year-old house in the village center; during prolonged rainfall, you can actually see the layer water pressing through the rammed earth / brick floor in the basement, because we are situated on a clay subsoil. All the neighboring older houses have the same problem.

There are certainly methods and solutions. First, you need to clarify how much you can or want to spend – or what you can accept. We have come to terms with it because the basement has been damp from time to time for 100 years, but it also dries out quickly. This was simply accounted for in the original construction. Options to reduce this are:

(1) – what we currently do – an adequately deep sump pump outside or in the basement at the lowest point to pump away rising water as effectively as possible. Advantage: the floor can be kept relatively dry. Disadvantage: there is definitely a risk of drawing in a lot of water since water naturally takes the path of least resistance.

(2) Drainage: sealing around the entire house and installing a drainage system below the foundation edge to divert water away from the building. The downside, to my knowledge, is that drainage can also work in reverse (meaning water can flow into the drainage system from the sides and then still seep underneath somewhere).

(3) Interior basement floor sealing, for example by installing a polyethylene (PE) membrane and then screed or similar. But in my opinion, this only works with a proper foundation slab – and there remains the question of where the water might come in since it is not a fully sealed envelope.

(4) It is apparently possible, with considerable effort, to retrofit a waterproof “tank” structure. However, I wouldn’t want to guess what that costs or whether it technically corresponds to the waterproof basement structures used in new builds.

Well, it’s not that extreme with the neighbors. The layer of clay and loam is relatively thin, and we are located on the edge of it.
A sump pit was considered. We already have that in mind as well. The fact is, we need a solution because our building services will be installed in the basement.

You just have to work with what you find. Simply put: if you have a bad feeling – don’t buy. Otherwise: pump sump and/or concrete base for the building services. 🙂