Hi, Can anyone see any problem with the following set up for a house wall? Outer layer (rain protection) compressed earth tiles treated with water proofer. then an inner cavity to allow for moisture and water to drip down the back of the facade tiles without getting onto the next layer which is strawbale covered by a one way vapour barrier. I ask this question because someone today advised me to also have a board of some type in front of the strawbale but I would have thought that the strawbales would be rigid enough to stop wind. Could there be another reason for the cement board suggestion? many thanks
Tiles, compressed earth or other, will not be able to sustain themselves with an airspace in front of strawbales; you would need a solid support for them, like cement board. That in turn would need support. I don't know how vapor-permeable these tiles would be, but it might be important to ventilate the space behind them.
Consider how the plaster skin provides much:
structural skin strength,
Water absorption/transmission/buffering reservoir
Durable, does not rely upon a membrane or rusted out brick ties, and is Easily repairable
Like said need a board to attach tiles if an air space, which probably defeats the membrane. Brick ties on air space rain screen is also self defeating. You could scratch plaster your bales, pinning ties. Once cured/dry, you could veneer out all or parts of the wall with your ceb tiles. I've done this with Adobes over earthen behind woodstove. You may want to consider rock, flag or brick for your bottom exterior courses depending on your ceb quality and location.