ᐅ Insulating the Outside of a Garage Against Moisture?

Hello everyone,

This is about a garage with two sides directly adjacent to the ground, due to its position on a slope. The back wall of the garage therefore needs to support the hillside.

These two walls and the ceiling of the garage are cast concrete reinforced with steel.
All other walls, which are free-standing, are built with brick masonry.

Question: Should the walls in contact with the ground be additionally insulated? The structural builder has not done anything in this regard.

The garage ceiling will also be sealed from above.

Regards

Yes, you have to. The areas in contact with the ground must be sealed (not insulated). Usually, this involves applying two layers of thick coating, followed by a dimpled membrane, and possibly drainage (required in case of hydrostatic pressure). Your building materials supplier can advise you on which materials to use and in what quantities.

Our U recommended applying two layers of waterproof slurry for a precast concrete garage. Additionally, the soil should not be placed directly against the garage wall; instead, leave a trench and fill it with gravel to improve water drainage. This might be visible in the photos.

I would also recommend applying two layers of bituminous waterproofing. (If you want, you can add perimeter insulation, but it won’t make much difference for a garage.) Instead of using a dimple membrane, it’s better to place drainage stones with a drain pipe underneath.

Ok, quick update. It’s waterproof concrete (WU concrete). Does that change anything regarding the matter?

A brief follow-up. The whole thing is mainly because the structural builder believes it’s not necessary due to the WU concrete?

You can place waterproof concrete directly into the ground. It is watertight.