Biochar plaster

I fell in love with earthen plasters during my cob course. It is nice to have a building material that you can wash out on the ground right next to your garden. It is nice to know what is in your home is not toxic to anyone, and the production of it is not creating any toxins elsewhere in the world.

It is nice to be able to source materials locally, to dig up my materials from the ground. This is much more affordable as well.

I have worked with clay based plasters and lime based plasters, and recently was introduced to biochar plaster. At the Ecovillage Training Center at The Farm in TN, Albert is the biochar man. I have to admit a little skepticism when first introduced to the concept of biochar, but there are so many people who report amazing results that I am sold. 

Recently the permaculture apprentices at the Ecovillage Training Center applied some clay based biochar plaster in The Prancing Poet (event space).  Albert mentioned that the biochar blocks electromagnetic radiation such as those that come from computers, microwaves etc. I was curious so I looked around and found a very interesting article on biochar plaster. 

Biochar as Building Material for Optimal Indoor Climate

by Hans-Peter Schmidt

The article mentions that biochar plaster is being used to restore old wine cellars. It regulates humidity for the wine, helps stabilize the temperature, and filters the air. 

I had yet to complete a final plaster coat on the cob bench around our woodburning stove, so I decided to do my own experiment.

I chose to use a 50/50 lime and masonry sand mix. with at least 20% biochar. The biochar was beautiful when wet, bluish-black. As lime plaster does, the biochar mix still smoothed into a nice finish after burnishing, looking almost like stone. 

I did have to baby the plaster a bit because humidity was low in the cold air, and I wanted to keep the cob at an ideal temperature for lime plaster curing so that I did not get large cracks (the last lime plaster I did was in ideal humidity and temperature and did not require water spritzing regularly as this mix did).

The plaster turned out great. I head to leave and come back to the Ecovillage Training Center, so I asked my husband to continue to spritz it for a week and keep an eye on it, then slowly decrease frequency of spritzing while it cured the our cold temperature with the stove running. I am very curious of the effect of the humidity regulating biochar on the lime plaster, but would need to try the plaster in different conditions to know that the change was related to the biochar in particular. 

I hear it is doing great and am looking forward to further biochar plaster on the walls. I will be keeping an eye on summer humidity in our home. I am looking forward to some changes in this!

Next time: More fibers, try a natural tint, do this plaster when it is warmer out!

Mosaic story floors

I started tiling last year when Sarah Haas came through and showed me what she leaned with Dan Phillips, other tilers, and then through trial and error of her own professional tiling efforts. She showed me how to tile with commercial thin-set mortar and grout with scrap tile. I decided that I wanted to complete the stairs with scrap tile and bottle caps. 

This year I started a new project involving bottle bottoms. I cut the bottom off of beer bottles with a tile saw and mortared them in.  To strengthen the bottoms (even though they are pretty flat) I filled them in with mortar as I set them. 

As always I had to try new things. I started with the thin-set mortar for tiles, but remembered how easily some of the tiles on the stairs had popped out pre grout. Instead, I grabbed a bag of premixed brick style mortar.  Once dry these tiles were not going anywhere. Thin-set mortar allows future changes if you may want to scrape everything up and try again, but after this much work with mosaic, I can't imagine wanting to redo the floor. 

I then mixed my own mortar for a bit, with local masonry sand from the quarry and a bag of portland cement. I found with this that sometimes there were still small pebbles that would make an uneven setting for the tiles and they would pop out. Next time I use this sand I will pre-screen.  Darrell, a contractor staying at moonCat right now, brought a bucket of fine sand scooped from a local property. Even though this contained a small amount of silt the mix held great, and this was my absolute favorite, until the cats found the bucket and made it into a litter box.

I did consider using an earthen plaster of clay, sand, starch, matrix material (such as straw, manure, etc.) and water. I decided against this because the house is in the ground. If by chance flooding occurred, I would need to redo the natural plaster and tile. With the amount of time I put into mosaic work, I think I will seek sustainability by using materials that will not need to be continually consumed, but will last for a long time (use of portland cement instead of natural plaster).

I did start with commercial grout, and decided to end with commercial grout, but recently spoke with a friend about mixing my own. My friend Michael (that I met at Earthships) recommended a fine sand mix very similar to the actual mortar I was making. He said mixing in the structural poly fibers used for cement may help prevent cracking. I may play with adding lime to the grout as well. At The Farm Ecovillage Training Center I had seen that the home Albert Bates was staying in had bottle caps laid in a lime plaster, but it did not hold well. Perhaps a mix of some portland and lime . . . and a little soaked sawdust?

I prefer to use natural or "waste" materials when possible. With this floor I used scrap tile from a mix of other contractors, the Habitat For Humanity Re-Store, and bottles and bottle caps that were being thrown away from local bars. I will admit that on one dark and frustrating night I decided to "Just finish it quickly!" by laying actual square tile bought from a store and did buy a couple of boxes of cheap tile.

I have come to realize that my tiling values include local material sourcing and waste/recycled materials as much as possible, but also there is a measure for my time and effort. I wanted to make the tree much larger with the bottle bottoms, but this is very time intensive.  I pushed myself for long days to complete the mosaic tile quickly and used all of my great TFH kinesiology pain releasing techniques to support days of statically bending over and mortaring in bottle caps and bottle bottoms. The tile portions go very quickly and are not quite so static. 

I can thank craigslist, local bars, and local flooring contractors for most of my tiling material! Thanks to Phoenix for all of her help placing bottle caps, and WWOOFer Chris Burke for hours of helping me to cut bottle bottoms.

I really enjoyed this project and have found it very rewarding. I am looking forward to more! As little girls at moonCat plot about who will own the house when I die I feel that my mosaic story floors can promote inspiration, creativity, culture beyond my lifetime. 

tiling in retrofit

This past summer we had someone come to visit who is interested in intentional community. She stayed with us for a couple of weeks and we discussed community and our experiences with it and shared knowledge. While she was here Sarah Haas shared her tiling knowledge with us.

Sarah is a dancer who decided that she wanted to build her own home and performance structure that could go with her as she traveled the states.  When she told me she had interned with Dan Phillips I was excited to pick her brain because I had found his TED talk very inspiring. Dan Phillips gave a talk on building creatively with reclaimed materials in Texas.  While there Sarah gained a foundation of tiling knowledge and then expanded her knowledge to do some tiling professionally.

The first project we worked on was a small table. Sarah cut cement backer board and we used Versabond thin set mortar to set the prearranged (largely by Phoenix) scrap tile pieces in place. I know that when working with plasters and cement the right mix means lasting work. Knowing this is a good brand and how particular Sarah is about work that will last I will probably stick with this unless I hear otherwise.

The line of blue dragons' tears down the center Phoenix collected somewhere random.

Once the mortar had been given enough time to set (about a day or check label) we squished in a reddish grout. Sarah was a little nervous about staining the tile with a darker grout but Phoenix picked red and we decided to go with it. Once applied we sponged it off the tile within 2-3 minutes and then wiped any remaining grout off the tiles with a cleanish rag. There was very little staining. A couple of the white tiles had the tiniest amount of color change.  After grouting we used a water sealant, and quickly scrubbed it off the tiles before it could dry on them and make them look foggy. 

I showed a friend later how to tile a coffee table. It was much easier to grout when we were able to keep the tile pieces level by varying the amount of mortar on the individual pieces of tile. When using scrap tile the pieces have different thickness and keeping the pieces level not only makes grouting easier but minimizes sharp edges that could stick out. 

The table turned out amazing! Second project: stairs. We have a few stairs leading down to the kitchen that are made of wood. Each stair had a small lip that stuck out. Jerome said that this is because of a visual effect and how our brains interpret depth. People are more likely to trip without that extra lip, but it would be really hard to tile. So I got out the sawzall and butchered the stairs as I cut off the lip. Then we laid cement backer board to support the tile and create and even surface to prevent future cracking. 

The tile we used came partially from what Sarah brought that people had given her as scrap and what a friend had given us from someone else's left over tile. I decided I wanted to get creative and use our collection of bottle caps that Phoenix had claimed. This was fun but did take a little longer to lay the bottle caps. We cut tile for the step edges to that there would be not sharp edges.  This was the first time I actually used my tile saw for tile. Previously I had used it to cut glass for bottle bricks. 

 I took the most time on the top stair. At first I really got intricate and took my time . . . then I decided the stairs needed to get finished more quickly because they were being walked on and pieces were getting knocked off and sideways. . . so a number of people chipped in to make our small community stair mosaic.

 Phoenix designed the center that looks like a ship anchor/bird and Jerome finished it by grouting her creation. Before she left Sarah designed the golden cap portion near at the right that looks like a sun and the trees on the side. Phoenix and our WWOOFer Sam from Utah designed the sides of the top two stairs. A WWOOFer couple from Ohio helped to grout and water seal a couple of the stairs. Our neighbor Donna contributed clear marbles left over from tiling her coffee table (I love how these feel on my bare feet).

When applying the water sealant I used two different brands. The brand "Miracle" that Sarah recommended seemed to soak into the grout much better. The cheap brand kind of rolled around on the surface a lot and needed a lot more work to apply. 

I love sharing knowledge and stories. It is fun to read the stories in our mosaic. The point beer caps are from every time Jerome's family visits from Wisconsin. The bird tile is a hot pad I found at a local thrift store and grabbed because I wanted to copy the bird for a sketch. Gluten free cider caps tell their own story. Some of the scrap tile came from a CSA member who snatched up a bunch of tile a friend was going to throw away and shared with us.  Jerome probably knows more about the other beer caps, and maybe which WOOFers drank each. . . or maybe not, but I really like the bottle caps and would like to do more with them. 

I can claim that the tiling fits in with sustainability because we are repurposing scraps and "trash".  Done right tile can last a long time, which also is a form of sustainability.  A lot of floors include poly something or other, and maybe some of my materials do;  I think it is minimized.  There is a bit of a trade-off in the use of mortar and grout with embodied energy, but creating a creative and lasting mosaic is worth it to me.

Tile can also be laid in an earthen plaster, but our home is in the midwest and partially in the ground so I want to avoid possible moisture issues by going with more traditional tile methods on the existing cement floor.