rebuilding top of chimney

[rmcfall]

I posted earlier about how the top of my chimney was struck by lightning and is now in need of repair. Unfortunately (but as expected), I just found out the brickyard cannot get brick to match the brick on my chimney. Because of this, I believe it makes sense to just repair what is remaining and reuse as many of the existing bricks as possible. Since I will be installing a stainless liner, is there any point in replacing the flue tiles that were destroyed? It seems like the flue tiles only function would be to give the liner's top-plate something to rest on...

 

[elkimmeg]

The flue tiles are a liner. If replacing with an ss approved ht 2100 liner, I see no problem, If using it for a wood stove.
For your fireplace to function, the opening area size determines the size of the flue liner. This used to be code but it still works as a rule of thumb. The flue has to have an area equal to 1/10 the opening size example.
30 by 30 " opening = 900 sq inches the flue cros-sectional area has to be near 90". In this case, one would have to use a 12/12 clay flue. The real code has grafts to determine flue size, which depends upon verticle run as well. The longer the run,(again this is to a point), the flue size can be reduced. If you are planning to add a 6" liner for a wood stove, you will not need to breakout the exinsting flues, providing you have enough passage clearance to get it threw, nor will you need to replace them. The metal liner is acceptable. Using as a fireplace you need a flue liner to equal your current vollume. Probably easier to use the clay liners replacing the damaged ones

 

[rmcfall]

That's pretty much what I figured....no point in spending money on clay flue tiles and installation of the tiles since I will be putting in a stainless liner for the woodstove. What is the "ht2100" liner? I know it has to be a certain grade of stainless (304, right?), but what is the HT2100 part?
Thanks,
Rob

The flue tiles are a liner if replacing with an ss approved ht2100 liner I see no problem, If using it for a wood stove.
For your fireplace to function, the opening area is size determines the size of the flue liner. This used to be code but it still works as a rule of thumb. The flue has to have an area equal to 1/10 the opening size example.
30 by 30 " opening = 900 sq inches the flue cros-sectional area has to be near 90" in this case one would have to use a 12/12 clay flue. The real code has grafts to determine flue size which depends upon verticle run as well. The longer the run (again this is to a point) the flue size can be reduced. If you are planning to add a 6" liner for a wood stove, you will not need to breakout the exinsting flues providing you have enough passage clearance to get it threw, nor will you need to replace then the metal liner is acceptable. Using as a fireplace you need a flue liner to equal your current vollume. Probably easier to use the clay liners replacing the damaged ones

 

[BrotherBart]

HT2100 is the designation for the Underwriters Laboratory testing procedure that tests a liner to withstand 2100 degree farenheit temperatures. Chimney fires are usually talked about in terms of being able to get up to and over 2100 degrees.

The UL Standard is UL 103 for the States and ULC 629 for Canada. The most common stainless steel used in the liners is 316ti and 316L.

 

[elkimmeg]

The 304 ss is a thiner weaker composition of stainless steel. It in its self, does not comply with code ,without being insulated acccorging to manufactures specs. Ht 2100 316 ti is a better grade of stainless steel and if tested to 2100 you are not required by code to insulate, it is suficient to stand alone. Insulation of a liner in an exterior chimney is a recomended application and I second that

 

[rmcfall]

thanks everyone!