Common Patio Installation Mistakes
We do at least a couple of jobs each year from people who hire a cheaper contractor and are now wondering if we can correct the mistakes. We can! Here are the most common errors we fix.
Improper grading
Either too flat or too steep
We recommend a 1.5% grade for Winnipeg soils. This is about a 2" vertical drop for every 10 feet horizontally. A slope that is more than 1.5% will be very noticeable visibly and as you walk on it – we want to avoid that. But less than 1.5% and it might work for a while, but with very minor surface movement, you can end up with water pooling on the surface. If an area of the surface slouches even slightly and one area rises a bit, you get water collecting in that area. If there was a bit more slope to begin with, it would still drain.
Complex draining designs
For some patios there will be a simple slope: the entire patio can be on a single plane, directing water away from the house. But grading becomes more complicated if, for example, the patio is between house and garage. We need to keep both buildings dry, so we create a swale between the buildings. This is more complex and it's not uncommon for installers to have trouble with it.
Improper excavation
Too shallow
If the excavation isn't deep enough it doesn't allow for adequate base depth.
Not fully removing old concrete, tree stumps and tree roots
Concrete piles located 18" to 24" below the patio can still telegraph up through the patio surface.
Stumps and roots will decay over time causing sinking.
Inadequate compaction
Without thorough compaction, the patio will shift and settle over time, leading to uneven surfaces, sunken areas, and even cracked pavers.
There are two key layers that need to be compacted:
- The subsoil – Before adding any stone, the natural soil beneath your patio must be compacted. If it's not, it will certainly settle later under the weight of the patio.
- The stone base – The base is compacted in “lifts,” which means it’s installed in shallow layers (typically about 2 to 4 inches thick). Each layer is compacted before the next one is added. This ensures that the base is solid all the way through — not just at the surface.
If you try to dump and compact all the stone at once, the top might feel hard, but the lower layers will remain loose. That hidden weakness is often what causes patios to fail a year or two later.
Poorly installed edge restraints
Poorly installed edge restraints allow the pavers to spread horizontally.
An edge restraint is a border that holds the outer pavers in place.
When edge restraints are poorly installed — or skipped entirely — the pavers are free to spread outward under pressure from foot traffic, weather, or frost heave. Gaps start to form between bricks.
A proper edge restraint:
- Is securely anchored into the ground with long spikes or stakes.
- Sits tight against the outermost pavers.
- Is placed on solid, compacted material, not loose soil or gravel.
Wrong materials
The wrong foundation stone
Using only 1/4" down gravel for the patio base will retain a lot of moisture, causing shifting and heaving. We use 3/4" down for most of the material in the base. This allows water to flow through. Then we add just a thin layer of 1/4" down right at the top to refine the grade before placing the bricks.
The wrong paver or slab
Not all pavers are built for the same purpose. Some are designed only for light foot traffic, while others are engineered to handle the weight of vehicles. Obviously this is especially important for driveways, but also for any area of a patio with heavier traffic.
Lack of geotextile
Skipping the geotextile layer between the subsoil and the base stone won't cause immediate problems, but it will reduce the lifespan of a patio.
Geotextile fabric acts as a separation layer, preventing the compacted base material from mixing with the softer soil below. Once the fine subsoil particles mix with the foundation stone, the foundation stone won't drain anymore.
Poor polymeric sand technique
Polymeric sand (often called “polysand”) is used to lock the pavers together and help prevent weeds, ants, and water from getting between the joints. But if it’s installed improperly, it won’t do its job — and it won’t last.
A common mistake is failing to compact the sand into the joints. Just sweeping it across the surface isn’t enough. The sand should be swept in, then vibrated into the joints using a plate compactor.
We're happy to help with any of these items! Just send us a quick email.
