Masonry heater build in tiny house

thomas rubino wrote:Hi Jordan;
Your stove is looking very nice!
I just love the old brick, it has such character.

I have found that when using new fire bricks , no mortar at all works very well.

I remember working on my shop batchbox during the winter...
A propane heater helped and then about 3-4 hrs was all my hands wanted to do.

thanks thomas!

yea i am enjoying the project immensely.

Maybe 3% of the bricks were new. the rest are all used. Some of the full sized firebricks were from a recent RMH build which was put in the wrong spot of a house(basement).

The majority of the red bricks are Baker, some are Dominion, and some are Clayburn.
My favourite to put on the wall is the Clayburn and the Dominion. They are flat on both sides and are accurate ( dimension wise)

A lot of the Baker bricks are inaccurate.



I need to get the door on my tiny house first before i can even attempt to heat the space ! Sounds like it is going to happen this weekend.



Does anyone have any suggestions for cleaning the bricks? What i mean is after i finish mortaring them? I was thinking a spray bottle with some water to wet the mortar and than a spoon or something rounded to sculpt the joints. I know when they striking the joints with concrete they do it before they finish for the day.

John C Daley wrote:

Its an interesting job

thanks! When are we going to see your build?

VERY nice!
I have a couple of questions.
1) I see you are using a layer of cardboard between the firebrick and standard brick. Is this an expansion joint? Do they move so differently as to need that?
2) Is anyone doing these with cob? If not, why not? Is it a similar problem of thermal expansivity, or weaker wear?

Nice build you have going there Jordan. Yeah, for cleaning mortared in place bricks of excess mortar, a spray bottle of water and a small brush, even an old toothbrush works well.

Re. April's question about the sheets of cardboard, yes, it's used to prevent mortar from falling into the air-gap and bridging between the core brick and outer brick "skin". Such mortar bridges, while the stove is coming up to temperature, would transfer unwanted force between the hot and expanding core to the much cooler outer brick body, resulting in cracks and fractures, and possible combustion gas leakage in certain situations.

Looking great Jordan! Any more progress on the stove? How abrasive are the Insulated fire bricks you are using compared to Ceramic fiber board? Do you think they will hold up well in the firebox?

well after enjoying a break from doing things.(please come back snow! ;) ) i spent the last few days working on the stove. Finished putting bricks on it and capped the top. Cut the ceramic glass, started a fire without a proper door installed. Top of the cooktop got above what my temp gun can read!


Water was spewing out of the chimney. Closed up the windows and put a wool blanket over the door(still don't have the door installed}. Managed to get it to 75* F. Took my sweater off and was enjoying myself.

so the stove seems to be running ok. There is still smokeback upon start up. and if i leave the door open to long while reloading it will smoke back. Lots of pulsating and flame spitting out the primary air.



Today!!! i Figured out an error

I went with the window delete version. I ended up making the back wall all the same. Which gives me a channel about 1.5" x 9" Whereas when i look at this post on the proboards it say the minimun shall be 2.5"
https://donkey32.proboards.com/post/23678/thread

That gap where my secondary monitoring window goes is crucial. It must not be pinched there, so I set those two bricks back. I've been suggesting to other builders to go no less than 2.5" at the narrowest points. In the first corner that should be corner to corner, like I show measured in the slideshow. I'm not sure what that is in mm, and I don't know what the true minimum is, but it starts to get finicky as that gap narrows.

than matt goes onto say

The window-delete version is a bit awkward due to that set back. A builder could remedy that if desired by slightly enlarging the firebox, or shortening the center wall, or using splits in the set back location, depending on what was behind it.

so i now think i have found my restriction!

2.5 x9 is 22.5
1.5x9 is 13.5!

Here is one example of what i could have done

So i thought about it for a long time and came up with replacing the last brick in the center. I cut it out with a reciprocal saw blade. I ended up slipping a 1 1/4" split into the space. Now i have around 2 1/2"+ for the gasses to travel through.

The stove performed much better! I still have a poorly sealed door. However i did not receive any smoke back when i reloaded the stove. Which with the old gap of 1.5" I would get smoke back.