I am planning to build a ground level dry-laid brick or concrete patio on soil that is subject to movement from freeze/thaw. If I use concrete, a reinforced slab on concrete piles will likely remain still while the soil moves away. I prefer to use brick which will move with the soil but I want to minimize patio movement and weed growth in the seams. I am in central Alberta where the soil is black gumbo clay, difficult to dig, very heavy, like concrete when dry, and sticky/slippery when wet. How does one work with soil that moves to create a durable foot traffic surface? I have lawn in the project area which is to be replaced with a hard surface patio.
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I would pour a floating slab. There would be no rebar because the slab would be divided into <5' squares. It would be formed up with Trex or some other synthetic wood. The forms would be grooved / keyed to keep the slabs alined with each other.
What about using a geotextile under your pavers?
The geotextile will keep the sand from migrating into the soil, but it won't do anything for stopping the expansion/contraction of the soil.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
2" subsurface insulating foam extending 1 1/2 times the frost depth past the edges of the slab. Example: if your frost depth is 4' and your patio is 10x20, with the 20' against the house, excavate a 16' x 32' area at least 8" deep. You will later cover the exposed foam with 6" topsoil around the slab. You can put 2" sand, or more insulation, under the slab so you don't have to pour a 6" slab. Use borate treated foam.
No more freeze.
Edited 4/11/2006 7:20 pm by SamT
Thanks, Sam. As I understand it your strategy is to prevent the ground under the patio from freezing. And the blending of frozen-to-protected ground is gradual enough that the patio area should not move.....or if there is movement it is reduced enough that the pavers or slab is not affected.
frost protected shallow foundationSamT
I checked the website you put me onto and got a better idea of what I need to do. Our temperature drop here is to -40 deg Celsius which is -40 deg F. The info on FPSF covers areas in Alaska and cold European countries also. THe recommendation is to keep the soil beneath, dry and to use insulation under the project. I will post results as I proceed. Thanks for the link!
Seen a sidewalk and patio poured over cardboard boxes. Crush boxes I believe they called them.
Just something I saw. Dont know anything about it.
when they put the boxes together, they were about 4 inches high or so.
Anyone else seen this.. or do it?