The concept of Permeable pavers has been around for several years but still few people (and contractors) dare to use it in today’s residential projects. This concept is more often seen in commercial and institutional projects.
This ecological technique will allow efficient management of storm water and excess runoff by returning water to the environment. This way the humidity does not accumulate in the foundation, as it would in a conventionnal 0-3/4” foundation.
We believe that the shifting of pavers and slabs, as well as the presence of whitish stains is due, in large part, to the freeze/ thaw cycles which can lead to the accumulation of humidity under your unistone.
Before digging, make sure there are no inground wires or gaz conducts.
– Determine the area to be paved as precisely as possible. It makes it easier to evaluate the material needed for your project. To ensure better stability of borders as well as pavers, excavate the equivalent of 1.5 times the depth beyond the surface to pave.
– In order to ensure sufficient drainage, it is recommended to excavate to get a minimum incline of 1% (1/16” per foot), then rake and level the bottom of the excavation WITHOUT compacting the sub-grade.
2- BASE and SUB-BASE
– Put down a woven bi-axel geotextile membrane at the bottom and along the sides of the excavation. Ensure that there are no wrinkles.
– Rinse away fine aggregates and debris, spread 3/4” gravel and compact with a vibrating plate or roller in 3 or 4 inch layers. When the application requires a base thicker than 12 inches you then proceed to creating a sub-base.
Becomes necessary for retention of a higher volume of water.
– Rinse and spread 2 to 4” gravel in 6 inch layers.
Pack down with a vibrating plate or roller until you see no movement of the gravel.
– Two inches of 1/4” gravel that should be leveled with a straight piece of wood or aluminum bar that you pull on 2 guides (2” diameter steel pipes) previously installed on the 3/4” gravel base.
4- LAYING THE PAVING STONES
– Ideally start at a 90 degree angle and at the bottom of a slope on an inclined area. Proceed by walking on your pavers, not on the installation bed (1/4” gravel).
– Leave a 1/4” gap between pavers to allow filling the joints. Some pavers are manufactured with spacers.
– For better results, it is recommended to use bricks from more than one pallet at a time. This way you get a more even distribution of colours and textures.
– For driveway applications, when you need to cut pavers, make sure the cut pieces are no smaller than 1/3 of their original size.
5- FILLING THE JOINTS
– Spread 1/8” gravel on a DRY surface. Spread the product all over the paving stones then work it into the joints by brush- ing in all directions. To make sure the joints are filled, run the vibrating plate one more time and brush in what is left over.
– Make sure your plate is equiped with a “paver saver” mat and that the surface of your paver is dust free before passing the plate. This way you limit scratches on your paver.
*this information is based on general applications in instances of complete infiltration. Other ways are possible too. For more specific projects, more information is needed; type of subgrade, it’s draining capacity, the volume of water to contain…Refer to a qualified engineer.