Masonry chimney questions

[Cyungle]

I am about to start construction on a masonry chimney but have some questions about my design:

I have two 8-inch diameter, 12-inch tall flue liners. I was planning on mortaring them together to make a 24-inch tall chimney but am not sure whether I need that height. I am considering using just one of them. Are there any considerations besides zoning restrictions that would make having a shorter chimney a bad idea?

I am going to build a brick chimney tower around the flue liner with regular clay brick and an air gap between the flue liner and the tower. Will the heat from the flue liner be too much for the non-firebrick tower or should I use firebrick to make the tower?

I am also going to fabricate a steel buttress frame for the brick tower to distribute the weight so it is not all centered on the arch. Are there any considerations about such a strategy?

Thanks - C

[Tscarborough]

Re: Masonry chimney questions

The higher the better for draw. You should not need any additional support for the arch, so long as it is sufficiently buttressed.

[stonecutter]

Re: Masonry chimney questions

I am about to start construction on a masonry chimney but have some questions about my design:

I have two 8-inch diameter, 12-inch tall flue liners. I was planning on mortaring them together to make a 24-inch tall chimney but am not sure whether I need that height. I am considering using just one of them. Are there any considerations besides zoning restrictions that would make having a shorter chimney a bad idea?

There are combustible clearances to consider, as far as zoning, that is a local issue. In my experience, there are little specific zoning restrictions pertaining to outdoor wood burning units, beyond common sense stuff.

I am going to build a brick chimney tower around the flue liner with regular clay brick and an air gap between the flue liner and the tower. Will the heat from the flue liner be too much for the non-firebrick tower or should I use firebrick to make the tower?

No need to use firebrick for the chimney and an air space between the flue and chimney is proper masonry practice

I am also going to fabricate a steel buttress frame for the brick tower to distribute the weight so it is not all centered on the arch. Are there any considerations about such a strategy?

What kind of an arch do you have? Centering the load on the arch is exactly where you want it.

Thanks - C

See above in bold.....

[brickie in oz]

Re: Masonry chimney questions

Why do you need the flue liner?

[stonecutter]

Re: Masonry chimney questions

They are not susceptible to heat damage like building brick, they protect the chimney, and they create a smooth chase for the gasses and smoke to escape.