Sealing between the floor slab and the reinforced concrete wall

Good morning,

I would be very interested in your opinions on the following matter: our floor slab was poured just a few days ago. The exterior walls are reinforced concrete walls. Due to the connection reinforcement, it is not possible to lay a bitumen membrane. Therefore, the bricklayer wants to apply a sealing slurry under the subsequently erected reinforced concrete walls. He plans to apply a bitumen thick coating later from the inside after the walls have been concreted.

My question is whether this is a good idea or rather counterproductive.

Thank you very much and have a nice Sunday.

Ask the bricklayer what he can do if you want a 30-year waterproofing guarantee. If you have pressing water, live behind the dike, have a basement in a flood area, etc., more information leads to more answers

Our construction company used Pentaflex joint flashing. However, we are located on a fairly dry slope without pressing water.

Hi,

If these are load-bearing reinforced concrete walls and no bitumen membrane can be applied underneath, this is not unusual at first – provided that a functional sealing system in a composite system is used.

A sealing slurry under the walls can work if the surfaces are prepared cleanly and the transitions are executed properly. What is important then is a continuous seal with overlap – for example, that the bitumen thick coating later connects seamlessly to the sealing slurry.

However, it is also crucial what water exposure you have – with non-pressing water or only soil moisture, this can be sufficient. With pressing water or high soil moisture, a joint sheet system (like Pentaflex) or a continuous white tank would be significantly safer and more sensible in the long term.

In short: The solution with sealing slurries and bitumen thick coating can work – but it strongly depends on the execution and local conditions. For safety, I would have a clean plan and a written execution recommendation from the structural engineer or site manager.

Have a nice day too!