Drying basement – pump sump | build septic tank yourself

Drying out the basement of my 120 year old house has been going on for 12 months now. In the interior, I have previously used the injection method to dry out. The areas above the barrier layer dry well and the indoor climate has also improved significantly.

In the injection process, holes are drilled into the walls at regular intervals and a liquid is injected into the masonry.

The liquid runs into the walls and spreads into the masonry. In this process, the pores of stone and joint compound are sealed. The walls become hydrophobic and waterproof.

The measured moisture in the masonry of the basement has since dropped from 1.6 to 0.8.

The basement floor is waterproof – How to dry it now?

Unfortunately, the injection solution has caused a negative side effect.

While draining the basement, parts of the injection fluid dripped through the holes and cracks, in the wall and in the false ceiling, down to the floor of the basement.

There, the injection fluid has spread and thus made the ground waterproof in many places. The water that runs into the basement during long periods of rain can now no longer run off and seep away.

The exterior walls were drained 5 years ago and a drainage system was installed. The sub-basement is located about 5 meters below ground level. The dimpled membrane on the outside and the drainage pipe are about 3 meters below ground.

Deeper this could not be laid without affecting the foundation of the house. The foundation consists of compacted sand and gravel. Water can therefore enter the building from below.

During long and heavy rains, I now have a small pool in the basement because the water can no longer drain through the floor.

Ultimately, even more water now soaks into the walls or evaporates in the basement.

Even if I will still improve some things in the outside area to stop the source of the water sustainably, I already have to take further measures in the basement.

I therefore built a sump, a soakaway, in the basement.

Build pump sump itself – My video

I have accompanied the entire construction with the camera and cut together a short but informative video. This video is part of my project series“Drying the basement“.

If you want to see more of me and my projects, feel free to check out my YouTube channel.

KG Pipe as shaft protection

To build my sump in the basement, I first dug a hole about 1 meter deep. A 315mm KG pipe was installed in this hole.

The KG pipe stabilizes the shaft and prevents soil and gravel from sliding down.

I drilled many small holes in the KG pipe. This is how to make a drainage. The stability of the KG pipe is still guaranteed. The ground under the pipe is filled with coarse gravel.

I also filled in crushed stone between the pipe and the surrounding soil. This prevents the soil from slipping and at the same time ensures that the water is well conducted into the KG pipe.

I then placed a drainage pump in the pipe which is supposed to pump out the water that now accumulates in the pipe. To prevent the pump from sucking in dirt or rocks, I placed a brick under the pump. The pump is therefore slightly higher.

Alternatively, I also considered placing a wastebasket made of a tight metal mesh as a strainer on the bottom of the tube. This also reliably prevents the stones from being sucked into the pump. With this method, the pump would also pump the water much deeper.

KG Steigrohr Schachtrohr DN315 DN400 Länge - 1m Kanalschacht Kanalrohr Abwasser (DN 315)*

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Preis inkl. MwSt., zzgl. Versandkosten

Zuletzt aktualisiert am 5. December 2023 um 13:15 . Ich weise darauf hin, dass sich hier angezeigte Preise inzwischen geändert haben können. Alle Angaben ohne Gewähr. (*) Bei den verwendeten Produktlinks handelt es sich um Affiliate Links. Ich bin nicht der Verkäufer des Produktes. Durch einen Kauf über den Link werde ich am Umsatz beteiligt. Der Preis ändert sich für dich jedoch nicht.

Submersible pump with integrated float switch

In the pipe I have installed a submersible pump. The pump has an integrated float switch. Therefore, it requires little space, but still has sufficient pumping power to pump the water up.

From a water level of 12cm, the pump activates itself and disposes of the water through a garden hose to the outside. As soon as the water has been pumped out of the soakaway, the pump switches off again automatically.

My goal is to later tie the water hose into the sewer lines or downspouts on the outside of the house.

Update:

A month later, however, came the nasty surprise! By a stupid mistake I almost destroyed the pump….