Waterproof Roofs the Natural Way – Update

Sooo, its been some time since I’ve posted last and I have some good and bad news to share with you. As is customary in delivering such information I’ll share the bad news first.

Bad News: I did not complete any of my theorized waterproof roofs.

Good News: I’m going to continue my research after I leave Aprovecho.

So all is not lost in my case. I think…

Some time after beginning my project it became clear to me that I was most interested in harvesting natural clay and firing it into ceramic tiles to use as a roofing material. After spending far too much time with clay and having many attempts at progress end in slippery disaster, I feel I have begun to get inside the mind of the clay. I feel like i have overcome the first big hurdle of working with this material and have an increased confidence for working with it in the future.

If you decide to follow in my footsteps and play around with clay, I will share a few things I’ve learned to compensate for the handicap of following my lead ūüėČ

Pro-tip #1 : Save your experimentation with large amounts of clay for warmer weather. Immersing your arm in a barrel of water and clay every couple minutes to check for lumps while mixing at 4 degrees C (39 F) is not a fun time. This would not be a problem if you were working with a more manageable amount / were working in or near a heated space / knew what you were doing.

Pro-tip #2: Partially hydrated (wet) clay is difficult to harvest and even more difficult to fully hydrate (dissolve in water). If at all possible try to harvest clay in its hard and dry form and leave it somewhere airy and dry to dry further before re-hydrating it.

Unfortunately I found this helpful website far too late into my time here, but the information therein is very useful – AND has some nice pictures, which this post seems to be lacking.





Waterproof Roofs – The Natural Way

 Modern conventional construction methods are resource-intensive, wasteful and rely heavily on unsustainable building materials. These materials may have high intrisic energy costs, be derived from the petrochemical industry and/or be sourced from areas hundreds of miles away from where they are used.

Steel and plate-glass dominated modern city highrises. The epitome of the conventional building ideology. (image credit: www.steelbuildingshub.com)

Natural building is a thoughtful and intentional counterpoint to this building culture. In Natural Building there is a high level of awareness about the sustainability of materials used, the proximity of source materials, and the minimization of waste.

Earthen materials dominate the structure of this mutli-story building in Mali. ( image credit:¬†Juan Manuel Garcia –¬†http://forum.skyscraperpage.com )

Despite this awareness there are still improvements to be made. For example a cob building can be constructed from the foundation to the roof rafters using only materials sourced from the building site itself or from sustainable local sources.

Shelter walls – stacked rock foundation and stem wall with cob on top. Cob is a mixture of sand, clay and straw. (image credit: Kent Griswold – http://tinyhouseblog.com/earthcob/cob-cottage-project/ )

Problems seem to arise when it comes to constructing the roof ‚Äď particularly the waterproof component thereof. Many ‚ÄúNatural Buildings‚ÄĚ still rely on steel, rubber, asphalt, EPDM, vinyl, or poly sheeting to waterproof the roof structure. It is unfortunate that in this one stage of construction there is a need to resort to using materials that cannot be harvested locally or produced on a vernacular scale.

Plastic waterproofing membrane for a green roof. Materials derived from petro-chemicals are often used as the moisture barrier between the roof structure and the natural environment. ( image credit: Clive Greenstone http://www.greenroofs.com/content/guest_features010.htm )

With the ideal of maintaining the use of natural materials throughout the entire structure of a Natural Building, I will be testing a number of experimental roofing systems in an attempt to create one or more alternatives to these unfavourable waterproofing materials.

Hopefully this will yield some interesting results that can be used in future research.

Please Comment!

     РCrusty Dusty