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DayCreek Journal

May 8, 2001

The Writing is in the Wall

Deb and Nick take turns at pointing and adding a few logs to the wall. A special thanks to both of them for their help with the wall and obtaining recycled materials to help build the house.

Literally. On Sunday, May 6th the first logs were placed into position marking the start of what will prove to be a long road towards completing the walls. I chose one of the back walls of the house to be the guinea pig. I figure if there's mistakes to be made, this is the right place to make them. (I have worked with cordwood in Rob Roy's workshop and a test wall made at home in Illinois, but this is the first real serious wall.)

As mentioned a couple of journals ago, I have decided to build the walls using a modified papercrete mortar. This is quite new to cordwooders to say the least. I'm taking my chances by using papercrete, but I feel quite confident using the material. The ingredients found in traditional cordwood mortar consists of either portland cement or mortar cement mix, lime, sand and sawdust. The purpose of the sawdust is to help retard the setting of the cement and to a lesser extent add R-value to the wall. I had considered replacing the sawdust found in mortar mixes with paper, but after researching papercrete I believe that more paper pulp can be added to the mix -- much greater than the traditional sawdust and mortar recipes. I would not however, consider papercrete for load bearing cordwood walls. The mix I'm about to describe is for non-load bearing cordwood walls only.

James Juczak has built his cordwood home using paper sludge from a pulp mill and type N mortar mix. Jim has reported no cracks in his mortar whatsoever. This in itself is quite intriguing to me. Mortar cracks are quite common with traditional mortar mixes used with cordwood. It appears that because paper soaks up so much water, the drying time of the walls is greatly extended. Does the extended drying time keep the mortar from cracking? I guess more research needs to be done on this. I do believe that some of this also has to do with the ratio of paper to cement. (My own experiments using papercrete mixes did cause a few cracks, but I was using much more mortar mix in the recipe, plus the walls were small in size causing them to dry more quickly.) Jim is using about 20% mortar mix to 80% paper pulp.

Papercrete is quite often mixed in huge quantities and poured into forms until dry. When using it with cordwood, much smaller batches seem appropriate. Here's a quick lesson on how to make papercrete mortar.

Give me your newspapers, comic strips, yellow pages...

Step 1. Soak lots and lots of newspaper for at least 24 hours. (A 55 gallon drum does a good job for me.) You can also mix other paper products, but newspaper degrades the best. The paper that I am using is a combination of newspaper, telephone books, envelopes, office paper, paper bags and who knows what else.

Step 2. Try to find a 15 gallon container if you can. My friends Nick and Debbie were nice enough to find me two barrels that were once filled with cow teat washer. (I'll keep you abreast as to how well they work.) These barrels are nice and tall to prevent a lot paper splashing up at you.

Just your typical recycled paper in a bucket with water.

Step 3. I start by putting in about a quart of water to the bottom of the barrel and then add about 5 to 6 handfuls of wet shredded paper. I then use a 1/2" drill with a spackle mixer and mix up the paper until it looks like gray cottage cheese. If the paper compacts down at the bottom of the barrel, you need more water. The extra water really helps to get things mixed into a slurry. Typically 2 to 3 minutes is sufficient to get the paper into a slurry.

Paper slurry just waiting to be squeezed.

Step 4. The slurry gets dumped out onto a large board. I first tried using a framed 1/4" screen, but the paper takes forever to drain. Squeezing out the water is much faster by hand, so now I just pile it on a board.

Step 5. Using my hands, I squeeze out most of the water -- not all of it. The squeezed paper pulp goes into a measuring container. A ice-cream bucket works fine here. Just be sure to use the same sized containers for both the paper and mortar mix.

Step 6. I add two thirds of the paper pulp to the bottom of the 15 gallon mixing barrel. I then add the mortar mix and then the last third of the paper pulp. Mixing both the paper and mortar takes only a few minutes and no other water is added. The paper holds plenty of water!

That's it. From here I scoop the papercrete out of the barrel and start mudding up the cordwood wall.

I have modified the mix a bit. The first batches were made with 25% mortar mix to 75% paper. I found that this ratio worked, but I found it difficult to point smoothly. Currently I am working with approximately 35% mortar and 65% paper. I find this mortar to point much easier and the plasticity of the mix is greatly increased. It has kind of a putty feel to it. Although this is probably quite a bit of "cement overkill", I really do like the characteristics of the mix.

I've also tried squeezing out more of the water before mixing with the cement, but this just made it harder to point. I could never get the right feel to the mix until adding more mortar. I could see adding some sand to the mix too, but I personally like the looks of a smoother mortared wall.

So why am I taking the chances with an unproven method? I guess I'm just plain hooked on the idea of taking newspaper and cement and building walls out of it. Our society produces so much waste, I feel that using recycled paper is a big plus for the environment. Also, the wall should greatly increase the R-value of the wall.

I have left the first wall to set for a week to see how it turns out. I'll update the journal with results in another week or so. Thanks for taking the time to read this rather long journal.

The wall is still quite wet. Once the mortar is dry, it should be quite a bit whiter in color.