Insulate the inner window reveal?

Greetings everyone,

we are slowly moving towards the final details of our planned single-family house. A friend of mine recently recommended that I should think about insulating the interior window reveals.

I am aware that there are nowadays special insulation products to prevent the stone window sill from getting too cold. But what about insulating the inner window reveal? Is it sensible? How feasible is it? Have you heard of it before or perhaps even retrofitted it yourself in a DIY project?

Let us know what you think, because it is probably no secret that the window reveal is definitely colder than the normal interior wall. The friend had mold problems in that area in his house (built in the 90s) in a relatively humid bedroom.

Best regards

You don't need it. If it should be necessary in a new building, either the window installation or the external insulation was massively botched.

Internal insulation is not necessary, even detrimental. Risk of mold growth, etc. With proper external insulation and installation of the windows, no problems are to be expected.

Risk of mold because water could accumulate between the masonry and insulation, right?

With our planned single-family house, we are slowly reaching the detailed finishing.

I see you are still light years away from that. What wall construction are we even talking about, and where is the installation level of the windows supposed to be?