Vapor barrier for exterior walls

In 2007 we moved into our low-energy prefabricated house (timber frame construction). The timber frame walls were underpinned with expansive mortar, on top of which were two-centimeter-thick wooden boards. The floor slab received welded membranes for sealing. I suspect that the vapor barrier of the walls was not properly installed. It should definitely reach down to the floor slab and be glued to it, right? In my case, it seems to have just been wedged under the exterior wall. At least, I feel a constant draft around the baseboards. I fear an impairment of the thermal insulation and possible mold risk for the screed insulation. How is such a vapor barrier properly installed?

Hello Tegger,

You should not feel any drafts; if you do, then indeed something was done wrong during the construction of the walls. In your case, I suspect a poorly installed wind protection on the outside of the exterior walls. Either a special windproof foil is applied there or a panel material that takes on the task of the wind barrier.

If the vapor retarder only tightly covers the inside of the exterior walls, that would be fine, as the vapor retarder is supposed to prevent the penetration of vapor and moving air into the wall insulation.