I am installing a wood burning stove in an off-the-grid Cabin in the Woods. I have a large supply of bricks readily available to me and I would like to build a thimble through the wooden wall using bricks rather than purchasing a wall thimble from a fireplace store. My question is how large a brick wall will I need to build to properly displace the Heat from the wood-burning stove pipe. I just want to make sure that this application is safe. I figure I can build it for just a couple dollars worth of mortar since I already have the bricks. What I was planning to do is to build a section of bricks into the wall that is 4 ft square with a hole in the center for the chimney pipe to go out through the wall. Any ideas from any chimney or fireplace professionals as to whether this is a safe plan? My limited knowledge of physics tells me that four by four brick wall would be sufficient to disperse the Heat and avoid a fire. Comments?

 

I'm a painter, not a mason but I'd be leery of a brick thimble. IMO the mortar joints would all be possible fail points. I haven't bought a thimble in a long time but I don't remember them being expensive. I suspect a fireplace store would be the most expensive place to purchase one.

 

Everything i have read so far tells me that virtually no insulation (double walled pipe, insulating wall thimble) is required when passing a stove pipe through masonry walls. I'm not concerned about failing mortar joints. A properly built brick wall should last decades. I just want to know how large of a brick wall is needed to safely disperse the heat. It makes sense to me that a few bricks, possibly even 2'x2' would be enough. After all, the bricks would only be in contact with the hot pipe for about 6 inches. Roughly 1 square foot surface area of hot pipe touching brick. Does anyone have any experience with this type of application? I know I can do this plan for 5-10 dollars in mortar. A standard thimble and double walled pipe are gonna run me a couple hundred. I always say "spend the time, save the money".

 

I don't know where you are shopping but for the few chimneys I built I used similar to this - https://www.menards.com/main/buildin...4441465212.htm It was placed in a masonry 'box' constructed of brick with a minimum of 8" of brick on all sides of the thimble. I used single wall stove pipe with these installations.