ᐅ Waterproofing of foundation slab for the load case of hydrostatic pressure
Created on: 10 Aug 2025 13:10
B
blablub
Hello everyone,
after the foundation slab was completed, it now needs to be waterproofed against the load case of hydrostatic pressure W.2-1E (we have occasional rising groundwater layers here). The planner roughly specifies fully welding the waterproofing membrane over the entire surface. A PYE Photovoltaik 200 S5 membrane is apparently sufficient here.
The question now is how the installation should be done beneath the masonry.
Two companies—three opinions. One says G 200 DD and to weld it to the surface waterproofing membrane. The other says to apply the surface waterproofing completely over the foundation slab and additionally install the G 200 DD underneath the masonry.
What is correct here?
The planner himself seems uncertain. Unfortunately, I have not found any detailed specification on this so far. Therefore, I hope someone here might be able to help.
Thank you in advance.
after the foundation slab was completed, it now needs to be waterproofed against the load case of hydrostatic pressure W.2-1E (we have occasional rising groundwater layers here). The planner roughly specifies fully welding the waterproofing membrane over the entire surface. A PYE Photovoltaik 200 S5 membrane is apparently sufficient here.
The question now is how the installation should be done beneath the masonry.
Two companies—three opinions. One says G 200 DD and to weld it to the surface waterproofing membrane. The other says to apply the surface waterproofing completely over the foundation slab and additionally install the G 200 DD underneath the masonry.
What is correct here?
The planner himself seems uncertain. Unfortunately, I have not found any detailed specification on this so far. Therefore, I hope someone here might be able to help.
Thank you in advance.
I spoke again with the TWP and the manufacturer of the bitumen sheets. Neither has a proper solution proposal. Unfortunately, the planner is not reachable, and the company is already eager to proceed.
I tried to sketch the assembly. This is at least how the planner designed it. The strip foundations were necessary due to the soil conditions, and the facing bricks are part of the existing structure and had to be preserved. The screed was intended to be a bonded screed on the concrete slab for the purpose of thermal activation of the concrete core.
The detail in question now is the cavity wall damp proof membrane under the masonry. According to the manufacturer, the G 200DD membrane is not approved for the load case. I am almost considering using the PYE Photovoltaic 200 S5 membrane directly under the masonry and omitting the G 200DD.
I tried to sketch the assembly. This is at least how the planner designed it. The strip foundations were necessary due to the soil conditions, and the facing bricks are part of the existing structure and had to be preserved. The screed was intended to be a bonded screed on the concrete slab for the purpose of thermal activation of the concrete core.
The detail in question now is the cavity wall damp proof membrane under the masonry. According to the manufacturer, the G 200DD membrane is not approved for the load case. I am almost considering using the PYE Photovoltaic 200 S5 membrane directly under the masonry and omitting the G 200DD.
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