A properly built paver patio has several layers working together below the surface: undisturbed or compacted subgrade soil, a compacted aggregate base several inches deep, a thin bedding layer of coarse sand, the pavers themselves, and jointing sand swept into the gaps between them, all contained by an edge restraint. Skipping or shorting any one of those layers is what leads to sinking, shifting, or gaps down the road.
Each layer has a specific job. The subgrade has to be stable soil, either undisturbed ground or fill that's been properly compacted, because anything loose underneath will keep settling no matter what's built on top of it. The compacted aggregate base sits above that and does most of the load-bearing work, spreading the weight of the patio and anything on it across a wider area. The bedding sand above the base is a thin leveling layer only, not a structural one, which is why it's a mistake to try to use it to fix an uneven base.
Base material and depth matter more here than in milder climates because of freeze-thaw. A well-graded crushed stone base lets water drain through it instead of sitting and freezing underneath the pavers, which is what causes heaving in a base that was built with the wrong material or not compacted correctly. The edge restraint around the perimeter is what keeps the whole system from spreading outward under traffic and frost movement over time, so it's a small piece that does a lot of work.
We build the base to match the actual site rather than assuming a generic spec fits every yard. That means checking the existing soil, the slope, and what the patio needs to support before deciding on base depth and material. Getting this layer system right the first time is the difference between a patio that stays flat for years and one that starts showing problems within a couple of seasons.
More on this from Chelo's Brick & Stone.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
