Light shafts in waterproof basement

Hello everyone,

although all the answers are correct, they do not really fit the problem at hand. I will try to clarify a bit.

1. Why does the basement light well extend above ground level?
This is because, in the case of unclear soil conditions, the ground surface level is assumed to be the highest expected groundwater level. When there are rain events, the surface water flows into the light well. If you raise it, this does not happen.

2. What does a light well cover do?
The described glass plate is only protection against heavy rain. Water can still get in.

3. Regarding the statement: "The windows are not submarine windows"
The light wells must be positioned in such a way that water can temporarily stand in the light well without reaching the windows, otherwise pressure-tight windows would have to be installed. There is a minimum dimension that must be observed so that the water has enough time to seep away.

4. Regarding the actual question: "How do you properly install light wells?"
To ensure watertightness at the connection, the insulation must already be fixed to the wall with suitable material and must not be water-conductive. So only XPS insulation can be used here. Then the light well must be glued and screwed with a special adhesive that is applied to the light well. The adhesive bead must be pressed out (only where water occurs, but I cannot see that in your picture).
There is also a primer for applying the adhesive to ensure bonding, otherwise too much water can come in from the side.

We installed the competitor's light well and used the manufacturer's corresponding insulation board instead of a normal XPS board. This was applied to the wall with a 2-component adhesive using a notched trowel in the "buttering-floating method."

The joint is tight and according to approval must be tight when executed properly. The contractor's statement that you just have to lay gravel is convenience.
I also can’t sell you a WU basement and say you have to install a drainage system so that the water does not exert pressure anymore.

If you have any more questions, please feel free to ask.

It would also be good to have some pictures of the installation situation.

Best regards,
Jann

I see little chance for the OP to recognize a professional execution of the sealing, and then later the drainage can be an effective means to keep water away from the basement area. In addition, all penetrations (water, sewage, telecom, electricity, etc.) should be constructed to resist pressurized water. Regards Nida

Normally, light wells are not sealed. It is important that water can drain away and does not accumulate there.

talk to the neighbors who have old houses,
topic water in the basement, damp years, dry years, water in shafts, etc..
From this you can draw certain conclusions and take measures.
And I still believe that anyone who builds a WU basement expects pressing water.
Where did this recommendation come from? It doesn’t come cheap.

Off topic again:

Anyone who installs a light well on a WU basement must connect it watertight. And that works too. Of course, there are other solutions, but the question here is whether the execution is correct for the intended solution. And that would be answered with "no."

I also don’t answer the question "How do I seal a flat roof?" with "Well, I think a hip roof with a proper tile covering is much better, because the water inevitably runs off there."

The question of why a WU basement was sold can even be read from the explanation of the question:

clayey soil, water drains poorly. In technical terms, this means "temporarily rising seepage water." This construction method is very common for this load case.

And yes, if a layperson looks at how it is supposed to look correctly, they can judge whether what is presented is wrong.

Best regards, Jann