distance to combustibles?

How far should a brick RMH be from combustibles? I am guessing the answer is, "It depends". Where can I learn what it depends on, and how to know what to do?? I have Matt Walker's Tiny cook stove plans. For this build, I don't know that insurance codes are a high priority... but i dont want to burn anything down. We are going to use concrete pavers for the stove exterior because thats what we could get. This is going in a small building - 12x28ish... and I'm trying to plan a floor layout, but need to know how far from other things the stove should be. Any principles or numbers to work off of??

I would tend to work from the International Building Code's spec for masonry heaters, which says 36" clearance where not reduced by various factors. If the wall of the heater is at least 8" of solid masonry (which would include cob), the clearance can be reduced to 4". Clearance to the ceiling must be at least 8" in any case.

I agree with Glenn. It is a existing standard that isn't too hard to abide by. It might earn you some brownie points if the grey area of insurance ever tries to rear its ugly head.

Thanks for the responses Glenn and Timothy. I see a lot of stoves on this forum that appear to be built against (or along) a wall... Are these folks not concerned with the code? Or should I assume that they have 8" solid masonry and a 4" air gap? Also would this recommendation be true for every part of the stove? Its my understanding that the bench is much cooler than the stove body. I am not really planning to build a bench on this because the space is quite small, and I'd prefer to us it for other things that can include storage. But in the Tiny Cook Stove plans, the chimney is layed out to exit the rear of the stove body before going up. I'm wondering if the chimney also needs to be 36" from the wall? That would really cause some problems for me... I can encase the chimney in brick at least to the top of the stove body. It looks like Matt's Tiny Cook stove is pretty close to the wall.

Matt's stove

First, I expect many builders are not familiar with or aware of masonry heater codes. Published plans by competent builders generally include safety precautions which, even if they don't follow the letter of codes, are actually safe in use. The bench being much cooler than areas next to the combustion core is a case in point. Stovepipes leaving a RMH mass are so much cooler than a wood stove exit that minimal clearances are actually safe. Chimneys that are not part of the heater should be built to code so that if the heater is someday replaced with a common wood stove the chimney will still be safe.

Hi Eloise;

Most of the outer skin of your stove will be in the 150- 250  F range except near the top.
If needed, a piece of sheet metal can be spaced 1" from a wood wall and the bricks could easily be within 4" or less from the metal.
A cheap laser temp gun can be used to monitor wood temps.

If you have the room, then allow a foot on all sides.

Thanks guys, this info is super helpful. Its been a while since I've had my head in the RMH stuff. Our building plans have taken many turns and delays, so my head has been other places for a while. We are getting back to the project on our land, and I'm having to refresh. I had remembered that the stove body temperatures were relatively low (at least compared to a box stove), along with bench and exhaust temps being even lower. So 36" just seemed like over kill to me. 4" seems a lot more reasonable. I figure if its not unsafe for a person to sit on the bench, it should be alright for it to be pretty close to combustables! Not sure if an insurance adjuster would agree with me on that, but I'm not stressing about that for this build.

I also contacted Matt Walker and his recommendation was in line with yours, Thomas. 4" from combustables, reduced to 2" if you use a heat screen like you described. Since the heat screen is itself 1" or more thick (made from 1xs), the heat screen is really only gaining you an inch.. so I think I'll just plan for 4" allowance all around. That is certainly obtainable!

Thanks again for your guy's input! Its really nice to be able to post something and get some reliable feedback quickly! Really appreciate it.