Raised paver patios are a character-filled and durable alternative to wood decks. Like any prominent feature in your landscape, you want to ensure that the foundation-building process is sound, for the long-term use and enjoyment of the patio. Let’s discuss the importance of proper installation of raised outdoor patios in Huntington Station, NY, so you can achieve a beautiful and long-lasting outdoor living space.
Here are four essentials that go into properly building a solid foundation for a raised paver patio.
Proper excavation is essential, to allow for at least 6 inches of base material below the patio. In some cases, excavation must extend below the frost line to prevent shifting during any freeze/thaw cycle.
Some installers fail to choose the right fill material or do not compact it properly. Using soil as fill for a raised patio can be a mistake. It’s almost impossible to compact soil completely—this results in uneven compaction and voids between the pavers and the naturally compacted subsoil (pre-excavation). If this occurs, these voids can’t support the weight of the pavers—or their movement—which can cause the pavers to crack, separate, or create a dangerously uneven surface. Pea gravel is another fill material. It is small and round, which means that under heavy load, it can migrate into neighboring soil.
Considered by some to a better alternative are limestone chips and dust (a mix of irregularly shaped and varied sizes of angular limestone pieces, from ¾ inches to dust). This is commonly called Limestone 411. Using a mix of sizes ensures that when the material is compacted, any voids are filled with smaller pieces and dust, which prevents larger stones from moving around and settling over time. The result is an extremely dense fill.
Geotextile fabric could also be used to further stabilize soil and fill material and prevent loss of fill material over time.
Compacting the fill material is another common challenge. The key is adding just the right amount of moisture both before and during compaction. Moisture helps release any air trapped between the stone chips, and helps bond stone chips and dust.
Aside from moisture, it’s important that no more than 2 to 4 inches of material is compacted at a time when using mechanical compaction equipment, or no more than 1 inch at a time if using a hand tamp. Improper compaction will eventually lead to settling, which will result in shifting and cracking of the paver surface.
If water pressure builds up behind a nearby retaining wall, it could eventually cause the wall to crack, buckle, or even collapse. This is prevented by using drain pipes, as well as managing water flow around the patio. There must also be adequate drainage off the patio surface itself: A 1% slope is often considered adequate for patio drainage, as long as there is easy egress for the water at the low point. If there is a seating wall around the perimeter of the patio, it must have drainage holes to prevent water from pooling on the patio surface.
If these four factors are met, a raised paver patio will be virtually worry-free for many years. Of course, experience and the right equipment also make a lot of difference to the longevity of a patio.