Peter Mauk

Gerry, thanks for your comments. That Stove Chat 31 was right on point - appreciate the link.

My conclusion now is to not worry about it so much - I’m going with perlite, no air gap.

As the Video points out, when you raise up the build to allow an air gap, you also automatically create pressure points under the supports, leading to uneven weight distribution, which is another challenge for the wooden floor that then must also  be addressed. Distributing the weight with cement board seems far wiser in my application.

I won’t ever be running it all day, or anything, i think. A cold spell here is a few weeks in the 30’s at night, but it rarely ever even frosts. So, major heat buildup under the stove will never be an issue.

My burn box is ceramic board. I’ll put a layer of fire brick splits under that, and 4” of perlite in a hardiboard “box” under that. Sound about right?

Best Regards.

Thanks for your reply.

I really want mass to keep the place warm for my dogs while I am away all afternoon/evening (I work the swing shift)... So, I think a flue pipe bench with mass is a better choice than a bell bench in my application.

The link you shared makes me think that an air gap is needed under the burn box (and maybe manifold) area to protect the floor, but not for the bench area. Perlite/clay, say 4”, might be good enough there.  Any thoughts?

My concern isn’t weight, it is keeping my vinyl flooring from melting.

This is my first build.

I rent single-wide house trailer (circa 1970, with 4” walls, unknown insulation, poorly constructed, 650 sq ft) that currently has no heat. Previous tenant used portable propane heaters. I am in Southern California in the hills above LA. It is noticeably cooler than living in the LA basin, but not as cool as the High Desert. It is about halfway in between the two, climate-wise. Heating Degree days is 2500.

I am going with a 6” RMH. I am using the Walker ceramic fiber core J design. I’ll wind up with something like Wisner’s 6” Annex design by the time I’m done.  Just out & back with a flat bench. 2.5 ft x 9 ft, roughly. Drum & chimney completes an L shape to the straight bench at one end.  I’m conscious of not putting too many turns in because my climate seems not cool enough to allow for great chimney draw.

I have a big pile of free red bricks to use and the local soil is very mineral rich, low clay, virtual no organic matter. I figure to just mix straight soil with fire clay for the cob, and call it done. Does that make sense? Is straw a necessary ingredient?

I am in the middle of reinforcing the suspended wood floor now to take the weight (easily done). It was 2x6 on 2 ft centers with 3/4” OSB and roll vinyl on top. Now it’s plenty hefty for the weight, but protecting the vinyl concerns me.

Plan A: Put greenboard, or masonry board, or something down on the vinyl. Put red bricks down flat on greenboard with plenty of air gaps (two-thirds air, one-third bricks, say). Put another layer of greenboard down. Build a rim of flat red bricks around the circumference. Fill the interior with perlite/clay, 2” (one brick depth) deep. Build up from there with cob.

Plan B: put greenboard down. Rim the circumference with vertical red bricks. Fill the interior with 4” of perlite/clay. Build cob up from there.

I’m not sure how important the air gap layer is for a wood/vinyl floor. Advice welcome.

Offhand, I prefer Plan B if the vinyl is safe that way ... less greenboard to purchase ... goes in faster ... and fewer spiders will move in under my RMH.

Thank you all for the forum and for being a cool community.

Hey Thomas!  Thank you for the warm welcome, and the welcome advice. That’s good news that I can use what I scrounged. Your rocket crew, as pictured, does inspire confidence.

I’ll start a new thread with my plans. Advice welcome.

This is my first build and i am assembling materials.

I scored some refurbished barrels with removable lids, but the lids have screw in bungs. Is that a problem?

Can I use this style lid as the top of an RMH barrel?
If so, do I need to do anything special to seal the screw-in caps?

Or, do I need to find a smooth, blank lid with no orifices?

Or, since finding a blank one is unlikely, should I just forget about having a removable top, cut the lid end off, flip the barrel and use the bottom as the RMH top?

Thank you.