Flex Liner Install Help

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
Sep 23, 2010
31
N.W. Iowa
I ran into something while installing my new flex liner and wanted to see what some of you thought. My stove is in the basement with an outside masonry chimney. The old clay thimble went through the brick wall in the basement below the outside grade by just a few inches. The outside wall of the masonry chimney is about three inches from the outside of the basement wall. The out thimble went between the two, basically just under the ground. I broke the old clay thimble out and found this out when dirt and landscape rocks feel into the basement. I am wondering if I need to do something about this or just put the new SS snoot for the Tee through the basement wall and into the chimney. It will then be covered with dirt or rocks for about three inches. I though about digging down between the chimney and the basement wall outside then put the snout through and seal it with caulk the best I can and maybe pour some concrete mix over it ???
 
your issue is very confusing
 
while earth itself is noncombustible, and an excellent insulator, the moisture issue you have with anything in direct contact with dirt is a problem. for a temp fix I might recommend using a piece of metalbestos or other class a chimney section to attach to the chimney, as it is all stainless and will not rot. Next issue: freezing. Anything less that 4' below grade is subject to freeze and thaw, thus a lot of movement. I would think that digging it out 10" around a stainless sleeve (8" round, preferably to accomodate many appliance oulet sizes), laying in 2" styrofoam aginst the raw dirt to prevent freeze against the earth, then pouring 8" of concrete all the way round the pipe to the styrofoam should solve the issue forever.
 
I think I would insulate it with liner insulation and then pour concrete around it. The insulation will prevent the heat from damaging the concrete if you were to have a chimney fire. You might also want to dig down a couple feet below and fill the space with sand or gravel to allow water to drain away.
 
burleymike said:
I think I would insulate it with liner insulation and then pour concrete around it. The insulation will prevent the heat from damaging the concrete if you were to have a chimney fire. You might also want to dig down a couple feet below and fill the space with sand or gravel to allow water to drain away.


you're gonna have a hard time damaging 8" of crete w/ heat.
 
summit said:
burleymike said:
I think I would insulate it with liner insulation and then pour concrete around it. The insulation will prevent the heat from damaging the concrete if you were to have a chimney fire. You might also want to dig down a couple feet below and fill the space with sand or gravel to allow water to drain away.


you're gonna have a hard time damaging 8" of crete w/ heat.

Even one inch.
 
If it got hot it could crack and being below grade moisture would then enter the cracks. Even though it is stainless steel I would not want to chance corrosion.
 
Sorry if this was a bit confusing, it was hard to explain. Thanks for the ideas everyone. My thought was to dig it down lay in some styrofoam on the bottom, form up the sides, install the snout, insulate it and then pour concrete around everything. My big concern was knowing it is not below the frost line and having freezing and thawing might damage something from heaving up and down.
 
It really depends on how deep your frost line is and the type of soil you have. The frost line here is 2' and I have seen plenty of buildings that have been built with a footing that is less than 1' deep. Many of these buildings are 50+ years old and have not moved at all or very little. It is due to the stability of the soil so I have been told by an engineer.

You could call an engineer and ask about your soil type and if he/she thinks you need to go below the frost line.
 
Status
Not open for further replies.