• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies living kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • raven ranson
  • Jocelyn Campbell
  • paul wheaton
  • Devaka Cooray
  • Burra Maluca
  • Miles Flansburg
  • Julia Winter
garden masters:
  • Dave Burton
  • Anne Miller
  • Greg Martin
  • Joylynn Hardesty
  • Mark Tudor
  • Pearl Sutton

Fireproof Concrete mix  RSS feed

Posts: 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I am looking for a good fireproof concrete mix. I am pulling out my Schrader Stove and replacing it with a rocket stove. My stove now sets on a brick hearth and surround and I plan to enclose the whole brick area. The area is about 4x6x8. So, I want to build my fire box with brick and fireproof concrete. Any suggestions?

Mark S. Leathers
Rolla, MO.
Posts: 2392
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Welcome to Permies, Mark!

Concrete is not generally thought of as "fireproof" because the intense heat of a fire can cause chemical reactions to take place in the concrete that weaken it. That said, there are refractory mortars that are useful for bonding chimney bricks together and they can be considered "fireproof". Generally they have a higher clay content and are made with more water than regular mortars so that they are runnier and make for a thinner bond.

Here is a link with recipes for refractory mortar.
Posts: 1245
Location: Okanogan Highlands, Washington
books cat dog food preservation hugelkultur
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Yup. 'Refractory' is the word you want; a thin-set mortar is fine; ideally you want it to be rated for over 2400 F, but something that can handle about 2000 will do if that's all you can find locally.

We often use fire clay (refractory clay) instead of chemical-set mortars; it's easy to work with, and doesn't damage the brick if something needs to get taken apart later (like to replace a cracked brick).

You can use ordinary concrete and cement mortars in the casing (outer 3-4") of the heater, just not in the firebox area.
If you do use Portland cement products, be sure there is a good expansion joint (a layer of flexible insulation or something like that) between firebox and surface masonry, so the firebox doesn't crack the concrete when it expands with heat. Earthen masonry is a lot easier to patch than cracked concrete; and it's also possible for the force to be relieved inward in ways that screw up your firebox.

Live a little! The night is young! And we have umbrellas in our drinks! This umbrella has a tiny ad:
Food Forest Card Game - Game Forum
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!