Papercrete And Me

I know that my little buildings will be easy to heat because they are so small and well insulated. The sun coming in the south and east facing windows should be enough to warm the interior surfaces. A good earthen floor will provide enough mass to hold the heat until night when it will be released back into the room.

But I know that just a few days of overcast and windy weather can really cool things off even in an energy efficient house. It’s good to have something for backup heat. Or maybe I am just looking for an excuse to have a fireplace because I LOVE sitting by a fire on a cloudy day or after the sun goes down.

I built a conventional Rumford fireplace in one of my previous projects. It came out nice but it was also very expensive and required a lot of exacting work. ( Barry Fuller has/had a pic of it on his site http://www.livinginpaper.com) Any who are following this blog know that attention to detail is not my forte. And now that I’m not employed I don’t have the $1200 or so the components would cost.

So true to form I decide to build my own kiva style fireplace. That way I could use what I had on hand and better size it to fit the room.

Carole Crewes’ new book CLAY CULTURE has some pretty simple instructions for builing a kiva so I dove right in and got started.

I decided to put it in the southwest corner mostly because that’s the only place available but also because it will be right next to the picture window with a perfect view to the Pedernal, the flat topped mountain made famous by Georgia O’Keeffe.

I had some 1/2 size cinder blocks left over from the last fireplace so I used them as a base. First I scraped away all loose dirt and leveled the area as much as possible, just by eye. I set the blocks in  and tamped them so they would sit firmly.

that the papercrete wall behind the fireplace would stay cool so I insulated it with a layer of pumicecrete. I formed an area with wire and poured a mix of pumice with just enough cement and water to make it harden up. I poured this down into the void

Pumicecrete between fireplace and wall

created by the wire.

To make the pumicecrete I mixed dry pumice with a little cement then added just enough water to make it stick. It was still easy to pour and almost dry but hardened up nicely in its wire form.

I continued with the base, adding a layer of adobe blocks then mudding over the whole thing with a cob mix. At first I was stomping the mix on a tarp as the book suggested but soon gave that up in favor of mixing in a bucket.

I wasn’t sure how to make a framework for the shape of the fireplace. I tried a few things that didn’t work then came up with the idea of taking wire and shaping it the way I wanted it then applying thin layers of the cob mix. I held a handful of mud against the wire and pressed it through using both hands. I built up layers from there until it was about 3″ thick. This seemed to work well. I took a piece of lathe that was sort of rounded, I guess for a corner (?) and used it to form the arch.

I wasn’t sure of the dimensions when I set the lathe for the arch and now it looks like it may be too high but I plan to finish the fireplace first, check the draw and then adjust the arch until the draw is good.

As I was going up I added a damper in the stove pipe just over the arch. It was a little tricky but I got it in there. The stove pipe starts just above the arch and goes out the roof about 2 feet.

Where the pipe goes through the roof I used more pumicecrete to insulate all the way around the opening. I made a sort of donut shaped cage or 1/2″ rabbit wire around the pipe an attached to the roof and filled it with the pumicecrete. I know papercrete doesn’t burn but I don’t want to take any chances with it smoldering and eventually turning my roof into dust.

So there is how I made the kiva fireplace.  For more detailed instructions I would suggest you get Carole’s book or the one by Becky Bee.

I will update this post when I finish and have had a chance to test the draw.

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This entry was posted by Judith on Thursday, January 6th, 2011 at 3:16 pm and is filed under What Was I Thinking???. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.