Papercrete for Mortar?

by | Jun 25, 2000

Pondering the Potential Possibility of Papercrete Mortar
During my visit to this year’s Midwest Renewable Energy Fair, I moseyed on over to Rob Roy’s booth to see what was new and interesting. Rob showed me a hunk of papercrete mortar that James Juczak made while experimenting with papercrete mortar. Jim is currently using papercrete mortar to build his post and beam cordwood home in New York state.

(I had heard of papercrete before but I was skeptical of its strength and durability, so it was low on my list of priorities. After I saw the sample, I decided to make it a high priority!)

Papercrete is made out of a combination of paper slurry and type N mortar. The paper slurry is quite commonly made out of old newspaper, but a variety of paper pulp products can be used. Once the mixture had cured and dried, the material that is left is very strong and lightweight. Most of the information that I have found so far, relates to papercrete as a building block material rather than mortar. Typically, the papercrete is made into blocks and used to build block walls.

The sample that Rob received from Jim was light in color, smooth to the touch, hard as a rock and lightweight. Jim wrote about his mortar experiments in the last CoCoCo papers and started using papercrete as mortar last fall when he started construction of his walls.

I spoke to Jim by phone this last week and he reports that his walls are holding up beautifully. Jim still has the second floor to do, but he did have some walls up before last winter and they survived the wet and cold without any degradation whatsoever.

A Visit to Paul Reavis
For those of you who follow the forum, a few months back Chris (3crow) brought up the possibility of using papercrete mortar and informed us of an article in Earth Quarterly News (Number 5) that had an article about Paul Reavis’s barn in Wisconsin that used papercrete mortar. After investigating, I learned that Paul wasn’t too far off the beaten path from my weekly trips to Minnesota, so Jo and I visited with Paul and his wife Sandy on Saturday evening.

Paul’s cordwood papercrete walls are probably the first of its kind. Paul built a cordwood addition to his barn in 1988 and it’s been holding up just fine.

Paul’s mortar mix consists of portland cement, sand and paper. The paper was not made into a slurry before mixing with the cement. He just simply mixed all of the ingredients together in a wheelbarrow. The only problem with the wall (in certain areas) was that Paul put the logs too close to each other. This caused a few cracks and weakened the wall in spots. This was not a fault of the mortar, but of log placement.

Jo and I had a wonderful time talking to Paul and Sandy and it was a pleasure meeting them. Little did Paul know at the time that he would be a pioneer in what might become a new form of mortar for cordwood homes.

I am pursuing this new form of mortar with great interest and I have already made a few test samples to see how this stuff works. I’ll be reporting my findings in a couple of weeks or so.

Here’s a few (subjective) pro’s and con’s that I’ve come up with so far regarding papercrete mortar for cordwood homes:

Pro’s

  • Cost Effective – You can get used newspapers or pulp waste for free and it cut’s down on the amount of mortar used in a wall.
  • Good for the Environment – Using recycled paper is a good thing. Less mortar is a good thing.
  • Simple – Mixing papercrete mortar only requires mixing paper, water and type N mortar.
  • R Value – It has been estimated that the mortar provides at least R 2 per inch.
  • No Cracks – Jim informs me that his mortar has not cracked during the drying process.

Con’s

  • Not Yet Proven – Papercrete has been proven to work quite well in the arid Southwest on adobe type homes, but the verdict is still out in damp climates. Time will tell. (With that said, you can increase the amount of cement in wet climates to make the mortar more durable.)
  • Water Seal? – It might be necessary to water seal the mortar near the bottom of walls that might get covered by heavy snows in the winter. (Again, this is somewhat dependent upon the ratio of paper to cement.)
  • Thermal Mass – With all of that paper and air, and less mortar, the wall will not have as much thermal mass as regular mortar. (But, your gaining R value in place of mass… flip a coin?)

If you would like to find out more about papercrete, there is a web site on the Internet that is devoted to the subject. Take a look at Papercrete News. If you have any information that you would like to share on this web site, feel free to email me or write a note or two for the forum.

And finally, this week’s Beanie Baby photo goes to Rosebud, Paul and Sandy’s pot bellied pig!