/ ? on proper install of wall in area subject to freeze - base preparation? #31
There are two types of shallow frost-protected foundation methods. One is for heated buildings, the other is for unheated. There are some differences in where all the foam boards are placed between the two. If you check out the links, you will find the two methods.
Revised Builder's Guide to Frost Protected Shallow Foundations (FPSFs)
At the above link, open the "Full Report" 752 KB pdf. On document page 17, there is a diagram for unheated showing foam below the foundation. The whole report is good reading and everything you need to know is there.
In either case, the foam is isolating the ground (with an ambient temperature of ~45*F) from the ambient air temps in winter. The foam does need to extend horizontally far enough to prevent the frost from reaching the part which is actually being protected--the foundation. There are charts for different regions which specify how far that horizontal foam apron extension needs to be, how thick, and how deep the foam is buried.
In common usage, a "frost wall" is something set deep enough to prevent heaving and usually consists of a footer poured in a trench that is as deep as the frost penetration in the area, and a poured or layed block wall that sets on the footer and rises above ground.
In your case, either poured or block walls will need some sort of lateral support. This could be ells at the ends, and tee(s) in the mid-section depending on the length of the wall. And, you need free space on the footer next to the wall to support the granite curbing.
The masonry walls can carry a lot of vertical weight, but they are fairly easy to push over from the sides. a strong wind can blow down a tall block wall that is not laterally supported, for example.
You can incorporate the lateral support ells and tees into a built-in seating bench, planter, outdoor grill, etc., etc., limited only by your imagination and budget. :laughing:
Yes - project creep - just a little.
Refer to post #19. :thumbsup:
It's a retaining wall you are building. They have different design parameters than a plain wall.
You should have drainage at the bottom of the wall. (Lowers pore pressure) The wall should be set on a compacted granular/clay base. If underplaying material is prone to frost heave try and remove it. ( material that will allow capillary action for water)
Forget the insulation and geotextile. More cost than true benefit.
If in doubt get the opinion of a geotechnical engineer.
Again, Post 19 :thumbsup:
Will cut granite stone, just plain granite boulders or flat slate stone count?