ᐅ What type of light wells should be used in case of potential water backup from drainage?
Created on: 9 Feb 2016 20:50
C
cumpaWe have poorly draining soil. Therefore, we need to procure suitable material to backfill the excavation around the basement.
We have two basement windows that are planned to have light wells installed.
We are building with a waterproof concrete shell ("white tank"). The general contractor wants to sell us waterproof concrete light wells for 1500€ each. Is there an alternative? Do we really need waterproof light wells? These two basement rooms do not necessarily require natural light.
But how can we ventilate if we possibly omit the windows altogether?
We have two basement windows that are planned to have light wells installed.
We are building with a waterproof concrete shell ("white tank"). The general contractor wants to sell us waterproof concrete light wells for 1500€ each. Is there an alternative? Do we really need waterproof light wells? These two basement rooms do not necessarily require natural light.
But how can we ventilate if we possibly omit the windows altogether?
Hi,
your general contractor must really like you, huh? First the heating, and now this?
Ok, the contractor can’t be blamed for the floor.
We also have a waterproof concrete (WU) basement that needs protection against occasional rising seepage water. The original plan was to secure only up to about the basement window height, but it turned out that the groundwater level at ground surface must be considered.
In other words, water level = top of grass turf.
We have six basement windows and considered three possible solutions:
1. Pressure-waterproof light wells with drainage pipes from the wells to a pumping shaft with a backwater valve, and from there by natural slope to the planned inspection chamber. Cost approximately 10,000 €.
2. Same as above, but without pressure-proof construction of the six light wells. This means accepting that in extreme cases water can enter these wells between the wells and the outer wall. The infiltrating water would be drained via the pipes and pumping shaft, but minor dampness and dirt marks could still occur in the well areas, which would have to be tolerated. Cost approximately 5,500 €.
So 4,500 € for six pressure-waterproof light wells equals 750 € per well.
3. Pressure-proof light wells without bottom drainage but with glass covers on top to prevent rainwater ingress. Cost 5,400 €, which is 900 € per well.
1,500 € per well seems expensive to me, unless a flood-proof basement window is included. Those alone quickly cost 600–800 €. We recommended them from the start and included them in our plan.
I would only omit basement windows completely if the basement has proper ventilation. Otherwise, sooner or later, you will end up with mold and decay in the house.
Best regards,
Andreas
your general contractor must really like you, huh? First the heating, and now this?
Ok, the contractor can’t be blamed for the floor.
We also have a waterproof concrete (WU) basement that needs protection against occasional rising seepage water. The original plan was to secure only up to about the basement window height, but it turned out that the groundwater level at ground surface must be considered.
In other words, water level = top of grass turf.
We have six basement windows and considered three possible solutions:
1. Pressure-waterproof light wells with drainage pipes from the wells to a pumping shaft with a backwater valve, and from there by natural slope to the planned inspection chamber. Cost approximately 10,000 €.
2. Same as above, but without pressure-proof construction of the six light wells. This means accepting that in extreme cases water can enter these wells between the wells and the outer wall. The infiltrating water would be drained via the pipes and pumping shaft, but minor dampness and dirt marks could still occur in the well areas, which would have to be tolerated. Cost approximately 5,500 €.
So 4,500 € for six pressure-waterproof light wells equals 750 € per well.
3. Pressure-proof light wells without bottom drainage but with glass covers on top to prevent rainwater ingress. Cost 5,400 €, which is 900 € per well.
1,500 € per well seems expensive to me, unless a flood-proof basement window is included. Those alone quickly cost 600–800 €. We recommended them from the start and included them in our plan.
I would only omit basement windows completely if the basement has proper ventilation. Otherwise, sooner or later, you will end up with mold and decay in the house.
Best regards,
Andreas
Hello Andreas.
The construction company responds briefly:
"If there are no windows, there is no ventilation, or a mechanical ventilation system must be installed, which needs to be routed up to the roof!
If standard light wells are installed, the high-quality construction method of a watertight concrete shell is no longer applicable."
At the price of 1500€ only the concrete shaft is included, not a sealed window.
The construction company responds briefly:
"If there are no windows, there is no ventilation, or a mechanical ventilation system must be installed, which needs to be routed up to the roof!
If standard light wells are installed, the high-quality construction method of a watertight concrete shell is no longer applicable."
At the price of 1500€ only the concrete shaft is included, not a sealed window.
Hi Cumpa,
you mentioned in your other thread that you already have a mechanical ventilation system installed. The basement rooms should actually be connected to it as well... and even if not, connecting them shouldn’t cost a fortune. If the basement windows and light wells are then eliminated, the general contractor should actually credit you for that.
Best regards,
Andreas
you mentioned in your other thread that you already have a mechanical ventilation system installed. The basement rooms should actually be connected to it as well... and even if not, connecting them shouldn’t cost a fortune. If the basement windows and light wells are then eliminated, the general contractor should actually credit you for that.
Best regards,
Andreas
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