I will install windows in a basement wall (made of concrete blocks) and will be mounting Leca beams over all the windows. The problem is that the Leca beams end up in the middle of the wall, so I have a problem getting mortar on the top side to attach upwards to the existing wall (making the holes minimally larger than the beam).
Question: Is there a good sealant/expansion concrete in a tube that can be used between the wall and the beam?
