Could a lime cob plus vermiculite be made for a membrane substitute?
it may be worth leaving an attic crawlspace from which to refresh the waterproofing treatment every so often.
I don't think this thin layer would stand up to roots & the house settling, unfortunately.
Jami McBride wrote:I was picturing laying this mortar/cement down to cover the wood and then continue with all the usual layers for a green roof. As far as I can tell I wouldn't have access to it once it was covered with all the layers. So I'm not following you here.
Cristian Lavaque wrote:
Kathleen, I've been wondering this same thing some time ago, so I'm glad you brought it up.
What I had thought I'd try when I actually get to build one, was trying a corrugated roof under the ferrocement. This way, it'd have a space that would separate the roof from the cement and moisture wouldn't accumulate there. That way, even if roots got through the ferrocement, they wouldn't go further. And the corrugated roof would also prevent it from making progress and adds an extra insulation from the living roof that could permeate the ferrocement. I hope that didn't confuse you...
I attached an image to better show the idea. There's the green, the earth, ferrocement, corrugated, wood.
Rob Roy talks about a clay that expands when it comes in contact with water, so it is self sealing. I can't remember exactly what clay it is.
He says it is expensive.
11 Waterglass Earthen Floors
This technique relies on using Waterglass, either sodium or potassium silicate, as a hardening agent for mixtures of clay soil and sand. This is a technique with which we have had much experience, but we feel that it is worthy of further testing in that the samples we have done turned out to be extremely hard and abrasion resistant. They were every bit as hard, if not more so, than earthen floor mixes sealed with linseed oil. Consequently, they provide another option for anyone not wishing to use an oils and solvents to harden the surface of their floor. This approach is based on experiments conducted at the Building Research Institute – University of Kassel, Germany.
Waterglass, is added to a mixture of clay soils and sand at the rate of 10% by volume. The sodium silicate needs to be diluted with water at a 1:1 ratio before being added to the floor mix. Additional water is added to attain a consistency that can be applied with a trowel. The one difficulty we have found with this method is that mixes containing sodium silicate tend to set up fairly fast and provide a limited window of opportunity to work them. One needs to get as good a surface as possible when applying the mix as it will tend resist further troweling.
In that sodium silicate does little to resist the absorption of water, another material is needed to seal the floor. One option is a product called Safecoat Penetrating Water Stop manufactured by AFM of San Diego, California www.afmsafecoat.com. It is a solvent free, acrylic based, low-odor and no VOC (volatile organic compound) formula.
Sodium silicate can be easily found through suppliers of clays and other materials needed to make pottery and ceramic products.
Emerson White wrote:
could you impregnate cotton, wool or linen with a heavy wax and then encase that in clay? I'd think you've get a few years out of that. Maybe try and get your hands on a bunch of second hand denim and sow it all together. It wouldn't be easy but it would be doable with DIY skills.