ᐅ Sealing between the concrete slab and the reinforced concrete wall
Created on: 27 Apr 2025 11:18
K
kamilov80K
kamilov8027 Apr 2025 11:18Good morning,
I would be very interested in your opinions on the following issue: our concrete slab was poured just a few days ago. The exterior walls are reinforced concrete. Due to the connecting reinforcement, it is not possible to install a bitumen membrane. Therefore, the mason wants to apply a waterproof slurry beneath the reinforced concrete walls to be built later. He plans to apply a thick bitumen coating on the inside after the walls have been cast.
My question is whether this is a good approach or rather counterproductive.
Thank you very much, and have a nice Sunday.
I would be very interested in your opinions on the following issue: our concrete slab was poured just a few days ago. The exterior walls are reinforced concrete. Due to the connecting reinforcement, it is not possible to install a bitumen membrane. Therefore, the mason wants to apply a waterproof slurry beneath the reinforced concrete walls to be built later. He plans to apply a thick bitumen coating on the inside after the walls have been cast.
My question is whether this is a good approach or rather counterproductive.
Thank you very much, and have a nice Sunday.
Hi,
If these are load-bearing reinforced concrete walls and no bitumen membrane can be installed underneath, this is not unusual as long as a functioning waterproofing system is used as a composite solution.
A sealing slurry beneath the walls can work if the surfaces are properly prepared and the transitions are correctly executed. It is important to have continuous waterproofing with overlaps—for example, ensuring that the bituminous thick coating later connects seamlessly to the sealing slurry.
However, the type of water exposure you have is also crucial—this approach may be sufficient for non-pressurized water or just ground moisture. For pressurized water or high groundwater levels, a metal flashing system (such as Pentaflex) or a continuous tanking system (also known as a waterproof concrete shell or “white tank”) would be significantly safer and more sustainable in the long term.
In short: the solution with sealing slurry and bituminous thick coating can work, but it strongly depends on the workmanship and local conditions. For your own reassurance, I would recommend obtaining a clear plan and a written execution recommendation from the structural engineer or construction manager.
Have a great day!
If these are load-bearing reinforced concrete walls and no bitumen membrane can be installed underneath, this is not unusual as long as a functioning waterproofing system is used as a composite solution.
A sealing slurry beneath the walls can work if the surfaces are properly prepared and the transitions are correctly executed. It is important to have continuous waterproofing with overlaps—for example, ensuring that the bituminous thick coating later connects seamlessly to the sealing slurry.
However, the type of water exposure you have is also crucial—this approach may be sufficient for non-pressurized water or just ground moisture. For pressurized water or high groundwater levels, a metal flashing system (such as Pentaflex) or a continuous tanking system (also known as a waterproof concrete shell or “white tank”) would be significantly safer and more sustainable in the long term.
In short: the solution with sealing slurry and bituminous thick coating can work, but it strongly depends on the workmanship and local conditions. For your own reassurance, I would recommend obtaining a clear plan and a written execution recommendation from the structural engineer or construction manager.
Have a great day!
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