wood burner stove to thimble

[Bill W]

I'm installing a 6" flexible liner into my single flue masonry chimney with a 7X7 inside diameter clay flue. The clay thimble is round and has a 8 1/4 inside diameter. In the past I had a class A triple wall pipe inside the thimble (it just fit). I pushed it against the vertical flue on the chimney side and connected the stove pipe on the stove side. The interior wall was boxed in with block between the 24" studs where the thimble comes through the wall and about 8" above and below the thimble. It looks like the blocking around the thimble to the chimney was done after the sheathing was put on the house and the masonry block was put up against it. I never had a problem with this but can't say for sure how far the plywood goes. I was always glad to have the triple wall pipe inside the thimble but now with the flexile liner and the connection to it I will only have the 6" single wall pipe coming through the 8" inside diameter flue connecting the liner Tee to the stove pipe. Any advice on how to insulate inside the thimble or do I even have to. Thanks

 

[begreen]

Chimney pipe (class A) going through a combustible wall is supposed to have 9" clearance. There are insulated thimbles to reduce this clearance. Here is an article discussing options:
https://www.hearth.com/talk/threads/chimney-passing-a-chimney-through-the-wall.147754/

 

[Bill W]

Thanks for the reply. The article on through the wall installation applies to everything I'm doing. The metal fab safe T thimble might be the way to go. Also, I just purchased a SS 6" round liner. To my dismay it doesn't fit into the flue. I'm going to have to remove the clay liner about 18'. If I remove the clay liner I will have room for the insulation around the liner which is good but I did like the idea of the SS liner in the flue I thought it would be safer. To remove the clay liner I was told I need a tile breaking tool. It is expensive and I will never use it again. Any advice on the best way to remove the clay liner and everything I'm doing would be very appreciated. Thanks again Bill W