happymappy
2020-04-02 20:26:56
- #1
Hello dear forum members,
I have encountered some challenges with the project of insulating the inner reveals of my balcony door with calcium silicate boards and urgently need your help.
On the one hand, after chipping off the plaster, I unexpectedly found a wood wool substrate with 4 large holes, which I filled with PU foam. On the other hand, at the top, there is a 3.5 cm thick mortar layer that is loose and thus presumably no longer load-bearing for the calcium silicate boards.
On the sides, I renewed the PU foam but now I suspect that, due to the wood wool surface, I cannot create a diffusion-tight transition to the outside even with smoothing plaster and sealing tape. If there is no objection, I will nevertheless make a smoothing coat with flexible adhesive at the transition from wood wool to PU foam and stick a sealing tape up to the plastic of the window before applying the calcium silicate boards. Does that make sense or should I do it differently?
Can I remove the loose mortar layer at the top and replace it with an XPS board without risking mold growth? If yes, how should I bond/fill/seal it? And is there anything I need to consider when gluing the calcium silicate board over the boards?
Thank you very much in advance for your help

I have encountered some challenges with the project of insulating the inner reveals of my balcony door with calcium silicate boards and urgently need your help.
On the one hand, after chipping off the plaster, I unexpectedly found a wood wool substrate with 4 large holes, which I filled with PU foam. On the other hand, at the top, there is a 3.5 cm thick mortar layer that is loose and thus presumably no longer load-bearing for the calcium silicate boards.
On the sides, I renewed the PU foam but now I suspect that, due to the wood wool surface, I cannot create a diffusion-tight transition to the outside even with smoothing plaster and sealing tape. If there is no objection, I will nevertheless make a smoothing coat with flexible adhesive at the transition from wood wool to PU foam and stick a sealing tape up to the plastic of the window before applying the calcium silicate boards. Does that make sense or should I do it differently?
Can I remove the loose mortar layer at the top and replace it with an XPS board without risking mold growth? If yes, how should I bond/fill/seal it? And is there anything I need to consider when gluing the calcium silicate board over the boards?
Thank you very much in advance for your help