Basement window wet / Water is running under the windowsill

Hello everyone,

we are currently still in the construction phase and have repeatedly noticed that water has entered below the window sill of two basement windows. Sometimes so much that the water ran down the wall to the floor or it was at least wet directly below the window sill. The shaft and the windows are not designed to be pressure-waterproof.

We have never been able to directly identify the cause so far, but we suspect that during rain water collects in the light well in front of the window, cannot drain sufficiently, and has therefore flowed into the basement room from window height. It is also possible that it flows in over the side into the light well...

We have addressed the site manager several times about this, who only said it will be resolved by handover. As a first step, the drainage of the light well has now been cleaned because it was apparently clogged with construction materials. In addition, a glass pane is now to be installed over the light wells to keep rainwater out from above. The groundwater stands about 30cm high at the basement.

The question, of course, is whether this is a suitable solution or just treating the symptom? To simulate this, we now want to pour 1-2 buckets of water into the shaft to see how quickly or slowly it drains...

How much water should the light well be able to drain and in what time, and is the idea of the glass pane a proper solution?

Would a backflow valve in the light well make sense, which also filters dirt?

Pictures 1 and 2 show the water flow quite well, picture 3 shows the shaft from the outside.

Thanks in advance for your feedback!

If groundwater is standing at the basement in your case, why was no pressure-waterproof design of the light wells chosen? That seems to me to be a defect. The light wells can also be connected directly to the sewer system, which might be a solution. But of course only with backflow preventer and odor trap.

If groundwater stands against your basement, why was no pressure-water-tight design of the light shafts chosen? That seems to me like a defect.

Hello,

the executing company decided in the implementation that this was not necessary due to the low groundwater level, hopefully it is not a mistake that we did not insist on it. The window itself is installed at a height of about 160 cm from the basement floor. The groundwater level is about 30 cm, i.e. approximately up to the floor slab. The question would be how high the level is at heavy rain?

The distance of the light shaft from the bottom edge to the window is how many cm? That looks like 10-15cm?

And please clean the drain of the light shaft.

The distance of the light well from the bottom edge to the window is how many cm? That looks like 10-15cm?

And please clean the drain of the light well.

The drain was cleaned, the picture is from before, since then we at least haven't had any visible wet spots inside below the window!

The distance is about 10cm, should be sufficient?

Structurally, there should be drainage and gravel below the light well to let the water run off.

I would set the shaft 30-40cm deeper.