I have made an opening in the wall to install a window and would like tips on what to use to fill in certain gaps with.
The wall is constructed of loose concrete blocks in two parallel rows with about 10cm in between. In cross-section, it looks like two walls, an outer and an inner. These two are connected at regular intervals, breaking the space and creating compartments. These compartments are filled with coke.
After making the opening, one compartment was emptied of coke, creating a void between the outer and inner wall. This void must be filled with something, otherwise, I have nothing to secure the frame screws to. I have considered plaster, mortar, or concrete. I also thought about using fitted pieces of LECA, but then I have problems with the frame screws, since LECA is not an ideal material for fastening and screwing.
So now I need tips on what I should do.
Externally, the wall will be clad with 10cm of foam insulation, so the risk of thermal bridges is relevant.
The void is about 7x10cm, as high as the window, and is on the right side of the opening.
The wall is constructed of loose concrete blocks in two parallel rows with about 10cm in between. In cross-section, it looks like two walls, an outer and an inner. These two are connected at regular intervals, breaking the space and creating compartments. These compartments are filled with coke.
After making the opening, one compartment was emptied of coke, creating a void between the outer and inner wall. This void must be filled with something, otherwise, I have nothing to secure the frame screws to. I have considered plaster, mortar, or concrete. I also thought about using fitted pieces of LECA, but then I have problems with the frame screws, since LECA is not an ideal material for fastening and screwing.
So now I need tips on what I should do.
Externally, the wall will be clad with 10cm of foam insulation, so the risk of thermal bridges is relevant.
The void is about 7x10cm, as high as the window, and is on the right side of the opening.
If the window is not too large. Fill the gap with polystyrene. Drill holes for frame screws in the top and bottom pieces near the side pieces. Insulate with joint foam.
If the window is large such that this attachment feels insecure, you can attach wooden blocks in the gap where the frame screws are to be mounted.
If the window is large such that this attachment feels insecure, you can attach wooden blocks in the gap where the frame screws are to be mounted.