Hello All,
Recently had my foundation cored and installed my thimble and through wall chimney pipe. The thimble is through my concrete foundation and within the thimble I am using triple wall class A chimney pipe. The picture below highlights my question. There is a very small gap between the thimble and the concrete wall, as well as the triple wall pipe and thimble. What can i use to seal these up? Some sort of non combustible insulation, foam or sealant? I can feel a significant draft through these areas so im sure they arent intended to be left like this. What products do you recommend? Thanks!
![[Hearth.com] Sealing Wall Thimble in a concrete wall](https://www.hearth.com/talk/attachments/20211128_103124-webp.286961/ "[Hearth.com] Sealing Wall Thimble in a concrete wall")
Recently had my foundation cored and installed my thimble and through wall chimney pipe. The thimble is through my concrete foundation and within the thimble I am using triple wall class A chimney pipe. The picture below highlights my question. There is a very small gap between the thimble and the concrete wall, as well as the triple wall pipe and thimble. What can i use to seal these up? Some sort of non combustible insulation, foam or sealant? I can feel a significant draft through these areas so im sure they arent intended to be left like this. What products do you recommend? Thanks!
