For a feature request, have a look at the left menu here which will take you to Feature requests. And also the wishlist in the forum.

There is a plugin that should calculate wall areas, although, probably not the way you want: ComputeWallsSurface. And one that calculates room perimeter.

That said, I am uncertain whether such a feature will be very useful; It is relatively easy to make rough estimates of most wall areas by multiplying wall length with (average) height and deduct the areas occupied by windows. Coverage-areas given by most paint manufacturers are not very accurate anyway.

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