Going to polish up the walls in a room in the basement. Around the windows at the bottom, there is a gap about 10 cm deep from the inner wall to the outer edge of the window. (see attached image)
Should I fill that space with mortar, or can I "fill" it with something like mineral wool? Or will that be too soft and crack?
Grateful for tips!
Should I fill that space with mortar, or can I "fill" it with something like mineral wool? Or will that be too soft and crack?
Grateful for tips!
