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4 replies
Casting concrete around a stove insert. How does it work when it gets hot?
I have some plans to cast a custom-designed concrete frame around a fireplace insert (Keddy 520P incl. installation frame). How does it work with concrete and reinforcement (expansion/cracking) when the fireplace gets red hot, are questions going through my mind.
What do you think and what ideas and tips do you have regarding this matter?
What do you think and what ideas and tips do you have regarding this matter?
The important thing is that you have airflow around the insert, otherwise you won't get any heat. I'm working on a project with an insert embedded in a Leca-wall. It will have four cm for airflow above/below the insert and 2 cm on each side. The chimney above should be connected "softly" to prevent cracks from forming when the stove gets hot.
It should be the same problem if you cast it tightly with concrete. The stresses when it gets hot could cause significant issues.
It should be the same problem if you cast it tightly with concrete. The stresses when it gets hot could cause significant issues.
On that particular Keddy I was looking at, there is a built-in frame you can purchase, which snaps in place with some leaf springs after being mortared. There's even a warning in the manual that says you're not allowed to mortar it in due to the risk of cracking.
Do you use reinforcement in the Leca closest to the insert when you mortar?
I've looked at some instructions for those prefab fireplaces you buy and assemble, and none seem to have any reinforcement. That's why I was wondering if it was because reinforcement doesn't expand at the same rate as the masonry and thus causes cracks?
On the other hand, reinforcement is used in the modular chimneys so they don't collapse...
Do you use reinforcement in the Leca closest to the insert when you mortar?
I've looked at some instructions for those prefab fireplaces you buy and assemble, and none seem to have any reinforcement. That's why I was wondering if it was because reinforcement doesn't expand at the same rate as the masonry and thus causes cracks?
On the other hand, reinforcement is used in the modular chimneys so they don't collapse...
No, I will not have any reinforcement. However, the chimney should be placed on a foundation so that it does not rest on the stove. Then maybe some flat iron might be needed in the construction, but not as reinforcement.
Between the stove and the chimney, there should be a piece of metal hose of a few decimeters so that the stove can expand without pressing against the chimney.
Between the stove and the chimney, there should be a piece of metal hose of a few decimeters so that the stove can expand without pressing against the chimney.
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