Non-Loadbearing straw walls

[nsainsbury]

Hi
My family and I are about to move onto 5 acres with a shed. The shed is going to be added onto, Bathroom and screened in area, and I would like to do the walls with rendered straw I have Three questions.
Can the walls be rendered staright onto the concrete slab?
There are already wooden supports in what will be the screened area. Where the walls meet them should the straw contact them and render around the lot or should I try to leave them mostly exposed? They just seem to be branches without any treatment at all.
Are there any problems with walling around the steel supports in what will be the bathroom?
I am worried about rotting the wood and a reaction with the steel and the wet concrete. I do not have much experience in building.
Help with these questions would be wonderful.

Nathan

PS Is there anyone out there living the permaculture life in the Whitsundays?

[Douglas J.E. Barnes]

Hi Nathan,

Don't place bails right on the floor. If you have a plumbing leak, you can face catastrophic decay in the walls - not something you want. You can place them on some manner of toe-up and render the whole works to the floor (you need to get the thing completely sealed with the render). For the finish, you can leave it like that or put in baseboards before your final coat. To make it easier on yourself, I'd finish the baseboards before adding the final coat then covering it in plastic to protect it (diito for windows).

I'm not sure I fully understand the second question. If my answer seems unrelated, please ignore it. You need to seal up the bale wall to protect it from moisture and to get the full insulative value of the straw (which I'm sure you know). You can run the render right up onto the posts, if you want it that way. But the straw must be sealed up.

There is a guy here in (cold) Ontario Canada who is doing bale infill homes with steel frames. Personally, I find the idea horrifying. Steel is very conductive, so it gets cold easily. This will make it a likely point for condensation. Condensation means decaying straw. I'd be careful. You are right to be worried. Perhaps you can insulate the steel with foam?

I hope that helps. If not, let's have another crack at it.

[derekh]

Douglas is correct about the cold and water vapour.

If you are going bale around the steel supports then have the supports on the inside of the wall not the outside. The theory being that the walls will insulate the posts and reduce condensation. If render is going directly onto the posts then wrap the posts in hessian / jute to "key" the render to the post.

Rendering a strawbale bathroom is probably one of the most challenging things you could do. Getting it wrong would be disasterous. Make sure you do the research first. Use waterproofing agents and damp course materials in the right places. There are fibreglass shower recesses available and one of these would help minimise water directly onto the wall or use a bath and tiles.

Good luck with it. I recently did a Strawbale course and had a great time.

derek

[nsainsbury]

Hi

thank you both for a speedy reply. The hessian to render sounds good and I had not thought of a 'glass shower recess even though I use the one at work regularly.

Thanks again

Nathan

[barely run]

There is a great bathroom down here at Rosnay Organic Farm...strawbale house but the bathroom is built on with corrugated iron walls and the floor is just fantastic. It is deep filled with river stone..loose stone ..with drainage through the stones into an enviro type septic system. There is one straw bale wall furtherest from the shower so less concern with sealing.
Cathy

[nsainsbury]

Hi

That sounds sweet. Since the water problem was brought up I have been trying to think of something different. I won't be doing that but I wish I could.
Maybe some more thought.

Nathan

[Honeychrome]

If you can find it down there, check out a book called 'Building Green' by Clarke Snell. It's a really well written and photographed document on the building of a small cottage using strawbale, cordwood, cob and.... hm, I think the last wall is something like 'modified stick-frame.' Goes into great detail about ground/stemwall/wall interfaces, moisture concerns, as well as strategies for connecting walls of differing construction techniques, which seems applicable to your situation.

That river-rock floor is a fantastic idea- I'm going to file it for use in an outdoor, solar shower I want to eventually build.