ᐅ Strip foundation with additional perimeter insulation and waterproofing
Created on: 16 Apr 2023 13:04
K
Kati2022Hello everyone,
Since our contractors have different opinions, I would like to ask for your views and experiences.
Problem:
We are building a house without a basement. Foundation – strip footings around 80cm (31.5 inches) deep. The footings are insulated with 12cm (5 inches) perimeter XPS both from the outside and inside. Under the slab, there is also 12cm (5 inches) of XPS insulation. Since the house is located at the highest point of the new development, our site manager believes we don’t need drainage. The site manager and the structural carpenter say that the exterior perimeter insulation does NOT need to be covered with an additional waterproofing layer. Installing a dimple membrane for plaster protection is optional. The plasterer is supposed to apply a waterproof slurry in the base area, and that should be enough. Hmm... Is that sufficient? Do the XPS boards protect the strip footings permanently? The window installer insists that he would definitely coat the footings with a bitumen layer and extend the dimple membrane all the way down to about 80cm (31.5 inches).
How have you waterproofed your strip footings (without basement)?
Since our contractors have different opinions, I would like to ask for your views and experiences.
Problem:
We are building a house without a basement. Foundation – strip footings around 80cm (31.5 inches) deep. The footings are insulated with 12cm (5 inches) perimeter XPS both from the outside and inside. Under the slab, there is also 12cm (5 inches) of XPS insulation. Since the house is located at the highest point of the new development, our site manager believes we don’t need drainage. The site manager and the structural carpenter say that the exterior perimeter insulation does NOT need to be covered with an additional waterproofing layer. Installing a dimple membrane for plaster protection is optional. The plasterer is supposed to apply a waterproof slurry in the base area, and that should be enough. Hmm... Is that sufficient? Do the XPS boards protect the strip footings permanently? The window installer insists that he would definitely coat the footings with a bitumen layer and extend the dimple membrane all the way down to about 80cm (31.5 inches).
How have you waterproofed your strip footings (without basement)?
A
Allthewayup16 Apr 2023 13:33Is the foundation slab made of waterproof concrete (WU concrete)?
Allthewayup schrieb:
Is the foundation slab made of waterproof concrete?No, as far as I know, it is not. It is a standard foundation slab; nothing special was mentioned in the quote.
A
Allthewayup16 Apr 2023 14:38A dimpled membrane does not serve as plaster protection but rather as a drainage protection in the ground and ends where the plaster begins. Perhaps there was some misunderstanding. If no waterproof concrete is used, I would definitely recommend applying a bituminous waterproofing layer as well. In case of issues, the wrong place to cut costs is on waterproofing or groundwork.
It shouldn’t make a huge difference either since there is no basement, so the effort should remain manageable.
I’m not entirely sure if this is strictly required by regulation, but if I remember correctly, all building elements in contact with the ground should always be waterproofed.
It shouldn’t make a huge difference either since there is no basement, so the effort should remain manageable.
I’m not entirely sure if this is strictly required by regulation, but if I remember correctly, all building elements in contact with the ground should always be waterproofed.
Waterproofing on perimeter insulation is largely unnecessary (unless you plan to use boards that are not moisture-resistant—but why would you?).
What might be necessary is waterproofing the strip foundations (i.e., before installing insulation boards), depending on the required water exposure class (ground moisture, occasional pressurized water, etc.) and provided they are not inherently resistant (for example, waterproof concrete construction). Of course, this primarily concerns potential rising moisture from the strip foundation to the floor slab, and you will likely have appropriate waterproofing on the floor slab itself anyway.
What might be necessary is waterproofing the strip foundations (i.e., before installing insulation boards), depending on the required water exposure class (ground moisture, occasional pressurized water, etc.) and provided they are not inherently resistant (for example, waterproof concrete construction). Of course, this primarily concerns potential rising moisture from the strip foundation to the floor slab, and you will likely have appropriate waterproofing on the floor slab itself anyway.
That a strip foundation must be fully waterproofed over its entire surface would be new to me.
Therefore:
Therefore:
Harakiri schrieb:
certainly an appropriate waterproofing on the slab foundation anyway
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