Replies

1. 
   Malcolm_Taylor | Jan 04, 2025 03:04pm | #1

   Clemkonan,

   Unfortunately there are no prescriptive paths to getting a rammed-earth house approved in Ontario - meaning you have to get the structure engineered. The second big impediment is meeting the building code requirements for insulation. Most of the resources for how to build these structures comes from warmer climates where they are more common, so take much the advice you find with a grain of salt. I don't mean to be discouraging, but thought it made sense to lay out the obstacles you will face.

   I don't see any reason why the designs that have been featured on GBA for concrete-free slabs wouldn't work with rammed earth.

2. Expert Member
   Akos | Jan 04, 2025 04:55pm | #2

   Malcolm makes an excellent point about design. One option that is used by straw builds is to build a post and beam structure with infill. Essentially the walls become a series of headers and jack studs which can be pulled from prescriptive tables.

   You would still need some real R value though. Despite the lot of hand wavy arguments, rammed earth is around ~R0.5/inch, so you have to get up to R24 if building under part9. Assuming 12" walls, you need about R18 somewhere. Simplest is 2x6 studs with cheap batts but could also use ~4" of rigid insulation. Nice part about exterior rigid is you can go with an EIFS finish which will be a heck of a lot less maintaince than any of the rendered coatings, I grew up in a place with those lime renders and there were never ending maintaince

   If you can build under SB-10, there are provisions for "mass" walls there that lets you use much less insulation but you are definitely needing an architect at that point.

3. 
   Clemkonan | Jan 04, 2025 05:10pm | #3

   Thanks however please note my bed and breakfast will be in the Caribbean. It will not be practical to ferry supplies over to the site so I would prefer not to do a concrete pour. Similarly to get the form works and use local soil would be great once I have the know how. I envisage a single story flat roof design with 3-4 bedrooms. Hopefully I can bring in a crew from Ghana to help me keep the cost down.

1. 
   Malcolm_Taylor | Jan 04, 2025 06:05pm | #4

   Clemonan,

   That changes everything. Various schools hold rammed earth workshops in both Canada and nearby New England, and what they teach will be applicable to the Caribbean - although I believe most North American builders use cement in their mixes, which you sound like you want to avoid.

   I would re-think using a plywood floor in favour of a tiled one on an compacted earthen floor base, which will be less susceptible to moisture issues.

4. Expert Member
   Akos | Jan 05, 2025 10:32am | #5

   Critters down south like wood, plywood on the floor might not be the best idea. You can do adobe floor if you don't want to deal with concrete.