Ensuring your
You will also need to incorporate some method of drainage, to make sure rainwater doesn't accumulate on the patio or around your foundation. Water sitting against the house will eventually seep in, leading to damp crawl spaces, a leaky basement, and a damaged foundation.
Plan your drainage carefully to ensure that rainwater doesn't flow directly into the sewage system and include a soakaway (a hole at the bottom of the lowest point of the patio, filled with loose gravel) so that any water has somewhere to go. This will prevent it from building up on your patio or driveway.
In most cases, we would recommend that you install a soakaway crate, in order to let the water seep away naturally into the ground.
If the existing concrete patio lacks a drainage system, it is a practical move to install one. In areas where the rainwater collects, cut a sloping channel. A well-cut channel directs the water away from the patio. Fill the channel with decorative stones or gravel so it meets aesthetic ideals.
Dig out the trench about 6 inches deep along the line, using a slope gauge to slope it 1/4 inch per foot. Dig a dry well about two to four feet wide and three feet deep at the low end of the trench. Line the trench with landscape fabric and gravel. Then lay in 4-inch perforated drainpipe with the holes facing down.
Water erosion is one of the most common reasons for a patio to sink or dip over time. Below all of the foundation gravel and sand is all-natural soil. This soil can be affected by water erosion causing a dip in your patio.
If your backyard doesn't have a natural slope, you can install a filter fabric or geotextile as they are commonly called. They are made of a permeable material that prevents the subgrade from moving while allowing water to drain. By installing this underneath your pavers, you could extend the lifespan of your patio.
Like any other Allan Block retaining wall, your raised patio needs to have proper drainage.
A concrete patio drainage channel like Slot Drain is the ideal way to protect your outdoor recreation area from the damaging effects of water. The most efficient option available, Slot Drain is a sleek, easy-to-install option that will easily handle any water runoff from your patio area.
Debris, such as leaves, soil, or twigs, can accumulate in drainage channels, eavestroughs, and gutters, blocking the water flow. When these channels are clogged, water is prevented from draining away efficiently, leading to pooling issues on your patio.
Pavers are permeable and are laid with small spaces in between them. These features allow water to run through them and back into the ground below instead of sitting on top, like it would with asphalt or concrete.
Mudjacking involves drilling small holes into the concrete and then pumping a slurry mixture of water, soil, and cement through the holes. The slurry fills the voids beneath the slab, and the pressure of the mix raises the concrete back to its original position.
Preparing the base
To lay a solid base for your paving slabs, you first need a layer of hardcore at a depth of about 50mm to 80mm over the area of your patio. Use a rake to distribute the hardcore, evening out any bumps, then add a layer of bedding mortar over the compacted hardcore.
You should never install the following over a drainfield:
Driveways. Pools. Patios. Tennis courts.
While it is possible to lay paving slabs on soil, it is not generally advised.
Usually with a standard patio, drainage underneath the patio is not required, so a woven membrane should work just fine. The woven membrane will help to stop the sub base of the patio from mixing in with the ground beneath which will avoid pitting, sinking, or wobbling of the patio slabs.
The recommended depth you'll want to dig to is about 150mm or 6 inches from the finished patio level. You can use a tape measure to check your depth is correct and once you're happy you can compact the soil using a Vibrating Plate compactor, also known as a Wacker Plate.
However before you lay down any paving slabs, you should consider a patio drainage system. By ensuring the removal of standing water from a patio (which can happen as a result of heavy rainfall) a properly installed drainage system can help you to avoid bacteria growth and even insect infestations.
Sealing Pavers Pro #3: It will help to improve the drainage around your installation.
Concrete Sand: A Common Choice
However, while concrete sand is a great option for paver bedding, we don't often recommend it as a base material because the soil underneath can compress and shift over time. In summary, the best bet is to use gravel as your base and concrete sand as your bedding material.
Once water accumulates beneath the patios or pavers, it erodes the supporting soil, followed by the sinking.
If rainwater is flowing directly onto your patio from a roof overhang or downspout, the water will pool in that area quickly. Installing a gutter system and redirecting downspouts away from the patio will usually correct the problem.