ᐅ Waterproofing of concrete slab without insulation in garage adjacent to residential building

Hello everyone,

Is there any reason not to skip the screed and insulation in an adjoining garage and instead seal the troweled floor slab with a two-component coating? The adjacent house would then have a standard floor construction with insulation.

You can do without floor insulation in the garage. However, you should insulate the walls facing the main house.

A smoothed trowel finish on the floor is usually sufficient. Whether a two-component coating makes sense for you is something you need to decide yourself. I initially planned to apply one, but after seeing it at friends’ places, I decided against it.

With insulation and screed, you should also consider the load, depending on how you intend to use the garage.

However, from my perspective, the most important aspect is the decoupling of your two floor slabs.

But if it's only smoothed without any coating, there is no waterproofing against moisture, right?

What type of moisture protection do you need?
Is it rising damp from below or moisture coming from above, such as water from a car, etc.?
As it is shown in the drawing, you currently have a thermal bridge from the garage floor into the house.

Both, actually.

The thermal bridge is a different matter but it makes sense, I think.