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This is a follow up to this question: How do I install steel dowels into the side walls of my brick bbq?

I have fit the dowels and they are working perfectly. However, the tiles on which the hot coals are placed are lifting/warping.

Here is a picture from before the dowels are installed.

enter image description here

I think the reason the tiles are lifting is because they are tightly packed together and the heat is causing expansion which leads to warping/lifting.

Apparently the tiles are heat resistant (although some of them have cracked). My parents had a similar installation and their tiles lasted more than 20 years with no lifting, cracking or warping.

How do I achieve a similarly long lasting installation? Is it just a case of using high temp mortar with more spacing in between?

Chechy Levas
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I want you to take a really close look at these tiles. Tightly packed tiles

Look a little bit closer. At the gap between the tiles, do you see how thin of a gap there is?

Your tiles are too tightly packed.

A lot of people think that mortars purpose is to glue tiles together. And it does that, but it has another use which is not mentioned but is just as important. Mortar is stretchy, even when it is completely 'dry' mortar is stretchy (compared to tiles). This allows mortar between bricks/tiles/etc to compress and expand as the tile expands and shrinks with temperature changes.

But in your pictures it looks like you barely have a 1/32" gap between tiles. They don't have room to shrink/expand as they warm up/cool down.

Ovens provide a very large change in temperature which causes oven bricks/tiles to expand/shrink significantly.

The fix.

Tear our your current tiles... Put a minimum of an 1/8" gap between each tile. And re grout them... It will work so much better.

Questor
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The firebrick in my wood-burner are not mortared in. They're set around the walls and held in place by a metal channel on top (which wouldn't really be necessary given the floor arrangement). The ones on the floor are just laid loose. Ash ends up filling any voids and providing some insulative value.

I'd consider two options, both of which avoid mortar altogether:

  • Overlay a second set of tile on the floor, staggering joints. Leave them all loose with small gaps at the outside of the floor.

  • Add a layer of the same firebrick we see around the walls.

One consideration is that loose tile is prone to cracking under impact. Maybe a bit of sand as a bed would help with that.

isherwood
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