Lateral sealing of the base plate

Hello everyone,

I want to waterproof the floor slab on the side myself, and due to the availability of materials, I want to order them early.
The house from the manufacturer ends on the floor slab with an aluminum Z-profile, which protrudes 10 cm over the floor slab. The prefabricated house walls stand on swelling mortar and are sealed downwards against the floor slab for water, animals, etc.

As insulation, 6 cm WLG40 still need to be added. This should be sealed upwards to the aluminum Z-profile with compressible tape. 1st question: The insulation: EPS or XPS, or something completely different?

The construction manager said that a seal should still be placed between the insulation and the floor slab (although many omit this). Would you seal it, and if so, how?

Regards, sciliar

Hello,

I didn't quite understand that.
Can you draw it?
Sealing on the outside side of the base plate or on the surface? Where is the insulation going?

Best regards, Jann

Hi,

I'm not much of a painter :-)
It's only about the side sealing. The base slab is finished, a prefabricated house will be placed on it. The upward sealing is done by the prefab house manufacturer when setting up the house, and then seals around the edge of the base slab up to 5cm from the top down the side. The house extends 9cm beyond the base slab; a Z-aluminum profile will be placed under the house for covering. On-site, we then have to install the lateral perimeter insulation, 6cm thick, all around, sealing upwards with compressible tape against the Z-profile. The question is: does another sealing need to be applied between the lateral perimeter insulation and the base slab, and if so, how (bitumen, sealing slurry, ...)? The house manufacturer said: it can be done, but it’s not necessary.

Ah okay - understood... Question 1 - XPS or EPS -> XPS Question 2 - A transfer of the waterproofing of 5 cm onto the side of the board is not sufficient. Of course, it depends on how much water is actually present. Therefore, I would recommend applying waterproofing. Regarding the question of what to use for waterproofing, the first question is again how much water to expect (soil survey?). Presumably, there is only ground moisture there, right? The house manufacturer will certainly weld a bitumen membrane onto the board. Then you need waterproofing that is compatible with bitumen membranes and that you are able to install. It would be best to also weld a bitumen membrane, but maybe you can't do that - then I would use a thick bitumen coating. You can always say "it’s not necessary" - but when it comes to waterproofing, I would rather spend a little too much money now than say in 10 years that it was not enough.

ah, an additional info: The base slab is not buried, only the lower 9 cm are in the ground, and only on 2 sides (one side is a carport, where paving will be done, the other side is on a slight slope). Plaster will be applied on the XPS insulation boards, and then this will form the plinth emerging from the ground. Alternatively, we are considering attaching a row of slate instead of plaster, but we just don't know how to fix slate onto XPS.

Hmm ok, then instead of xps you could also use special EPS base plates, but I still recommend xps with structure otherwise the plaster won't hold … the plaster should also be a moisture barrier - this is available from well-known manufacturers and is always called something like Flexyl etc. If you build it up like that with Flexyl from the outside, you can also work on the board with a mineral waterproof slurry