Natural Roofs

Janine Bjornson is a natural builder, practitioner and educator. She began her career in natural building when she trained with The Cob Cottage in 1996. Since then, she has taught over 65 workshops in Canada and the United States, from east to west. Her passion for building with natural materials bloomed out of her love for the earth, in conjunction with her concern for diminishing ecological resources and toxic buildings. As a result of this, Janine has devoted the last 14 years to immersing herself in the world of natural materials and the knowledge of how we can shape dwellings that are healthy, healing, inspiring, and beautiful. She has developed a penchant for natural paints, and plasters and loves the concept of “naturalizing” any kind of home. She loves to share this knowledge with others and this is evident in her enthusiastic teaching style. Janine has assisted in organizing 2 Natural Building Colloquia. She has presented at the Natural Building Colloquium in Bath, New York, Kingston, New Mexico, and Kerrville, Texas. She taught the hands-on natural building component of New College of California’s EcoDwelling program, and Dominican University’s EcoDwelling program. She lives in Sebastopol, California. www.claybonesandstones.com.

Questions and Answers

Q: Could recommend a natural roofing system that would be compatible with a mobile?

A: (Kelly)This is a tough one. I suppose it would be possible to do some sort of thatching up there. If you are thickening the walls you will need to create a new roof anyway, so thatch, or tiles might work...all depends on aesthetics and materials availability and your budget.

Q: Is there a way for me to make a form or pattern for a terra cotta roofing material made from this South Carolina red clay that is abundant here? I hope you can point me in the right direction. I have this idea to use a pvc pipe to act as a form for the tile and to bake it in an outdoor oven on my farm.

A: I have never done this work, therefore I contacted a friend that has had some experience with this. Here is what she said.....

The typical traditional thing is to use a wooden mold and lay the clay mix for the tile in a slab over it for forming. These molds are usually tapered at one end. I've been playing with using a used roof tile, purchased from a building recycling center, as a mold. Depending on diameter and taking into consideration shrinkage of the clay a PVC pipe cut to length should work
just fine. Clay has the great ability to hold shape memory and retain it after it comes off the mold, yet before it is dry. In Mexico we would stack them right into the earthen kiln wet and keep a small fire going to dry them. Once dry they were stacked in a 'house' and fired in groups of 2,000 or more for three or four days.here are many ways to do it and the most important thing is to find the right material and mix that can handle the form and fire.

Q: I am building a home on an island in Thailand. I have been thinking of using Thatch or Bamboo for roofing. I like the Spanish tile idea for bamboo, but the property does have termites. I recently toured the Greenschool Campus in Bali, where they immerse Bamboo in Boric Acid to make it insect resistant. The Thatch that is locally available needs to be replaced approx. every 5 years but I read about Water Reed Thatch that is more durable, but I cannot find any articles about it being used in a Hot, Humid climate like southern Thailand. I would appreciate any thoughts and insight into using either.

A: (Peggy) Yes, in Thailand people do not use water reed for thatching.  There are a few kinds of reed but they are not so accessible and have not been used for thatching.  You would need a ton of them as well and if you are on an island that would be really difficult to get.  I recommend using the local palm thatch but making very steep roofs and attaching it close together making it as thick as you can.  Making a steep roof will make it last much longer as the water will run off quicker and make it rot slower and you can make it thick if it is steep whereas if it is not steep it will start to flip up if put on thick.  They usually recommend at least a 45 degree angle on the roof.  The palm thatch is quite a bit more long-lasting than the grass thatch we have here in Northern Thailand.  This kind of roof if done steep and thick should last you at least 10 yrs but in our tropical climate of Thailand it's hard to get thatch to last much longer than that.

As for bamboo tile, that is done in Laos often, but it needs to be replaced quite often (every few years).  We don't have a lot of experience with boric acid but usually that is for insects whereas the bamboo Spanish-style tile tends to rot which I don't think the boric acid would prevent.