Paver Laying | Flagstone
First Make a Plan
Even before buying pavers you should have a plan. This way you will ensure yourself of a professional finish. When working out a plan, it is best to work in a systematic way, marking out the areas with a can of dazzle (spray paint ) to help visualize the area. We need to tie our patio and driveway with existing trees, planting beds and decks. We measure everything and make a small scale drawing of our home and existing landscape on paper. We use a straight edge with a level on it and a tape measure to get a rough idea of how much our yard sloped (we noted that on our drawing as well). Once you complete the concept plan, mark it down on a planning sheet in pencil, from there calculate the quantity of pavers and raw materials required. A well-designed patio or driveway must take into account the terrain, landscape and the needs and budget of your family. If you have any trouble calculating the quantities from your plan, call into you local paving manufacturer and they will assist you in calculating the quantities of your raw materials.
The first step in excavating the area is to mark it out with dazzel or string lines. Then calculate, using string lines, your finished heights ensuring that you allow adequate slope for drainage. Then remove all vegetation and soft soil to a depth equal to paver + bedding sand + base-course. It is important to consider, the disposal of the surface water, as excess water can undermine the base, it is recommended that excess water be removed by the use of strip drains or like products.
Building a Base
Using the correct sub-base is essential, as one of the most important factors in ensuring longevity in your pavers is good drainage. Most paving failures are caused by lack of or incorrect base material being used. It is recommended that the minimum depth of base course used is 50mm in paving and 100mm minimum in driveway applications. All base materials must be compacted by the use of either a plate vibrator or some other means of compaction.
Well graded, course textured bedding sand (not beach sand) should now be spread over the compacted base course layer. To ensure a consistent layer of sand, screed rails (25mm water pipe) and a screed bar should be used. Place the screed rails on the surface of the basecourse in two tracks slightly narrower than the screed bar, then spread the bedding sand over and between the rails, ensuring that the sand is 10mm above the height of the rails. Now compact the sand, when the sand is compacted, use the screening bar to level the sand, always working backwards to avoid walking on the finished sand.
Preparation for Laying
You should now have an expanse of flat sand ready for laying the product, but before you can begin you need to set out the appropriate string lines to ensure that the job remains straight. You will also need to ensure that your lines are straight and square. This can be determined by laying out a right-handed triangle (3,4,5 triangle).
Lay the border pavers (header course) and ensure that this is straight and level.
Place the pavers in the desired pattern flat and gently on the sand bed, making sure that they are hand tight. Ensure that there is a 2-3mm joint is created between the pavers.
Ensure that care is taken to work to your string lines, adjusting the pavers to fit.
Lay the full pavers first, then measure the pavers required for any cutting. Pavers should be cut using either diamond saw or a masonry blade on a circular saw.
Edge restraints are essential to prevent movement of the pavers in the sand. The restraints should be set approximately 10mm below the finished height of the pavers. Ensure that the edge restraints are substantial and permanent, suitable examples are a concrete haunch or ground treated timber. The concrete haunch should be approximately 100mm wide and 100mm high, and finish 10mm below the finished height of the pavers.
Now that the pavers are all in place and any cutting is completed, you need to now apply dry jointing sand over the surface of the pavers and sweep into the joints, until the joint are completely filled. In a driveway application, you may use a plate compactor to assist in sand penetration. Finally sweep the excess sand off the surface of the pavers, keeping in mind that the procedure will need to be repeated at a later date to ensure adequate levels of jointing sand.