Hello,

I am looking for advice on forming up my grade beams for my 1000 square ft. rectangle of a house.  Its for a concrete free slab/ sand box and the structural engineer specified 1 foot wide grade beams that can be done in a single pour.  Its trenched on 3 sides and will sit on 6 inches of compacted gravel all the way around.  The site has a 10% grade.  The western wall will be a 2 foot pour and is trenched.  The eastern wall , meanwhile, will be a pour of 42 inches and will not be trenched, thus accommodating the slope of the site.  The north and south walls will be tapered between the two.

So, the 1 foot wide, 42 inch tall eastern wall is my biggest concern.  I am a carpenter but have largely avoided form work over the years.

Here what I have so far:

1. I am looking for advice on ties.  I am leaning towards sandbaggy snap ties and they will be independent of the studs and whalers (not tied in).   What is the suggested spacing in this case?

2. Plywood.  I would like to use 5/8 zip, since I could reuse it, but would 3/4″  be best for a 1 foot wide pour?  Finished side in and presoaked (sprayed) to help with cleaning up the forms, right?.

3.  Studs and whalers.  I will use 2×4’s.  I imagine a grid.  Which is best for bracing, having the studs or whalers make contact with the plywood?   

Thanks,

Stephen