Stone pavers are one of the most beautiful materials to use for paving. Done correctly, they have a European elegance and robustness that is hard to match.
Pavers come in various types of materials, including granite, porphyry, and even concrete. They can be laid on a sand base if they are at least 60 mm thick and grouted with gravel, sand, bitumen or mortar. However, for best results they should be glued to a concrete slab and this article discusses this procedure.
Pavers can be purchased as individual stones or already glued in a pattern to a mesh backing. The mesh backing allows for quicker placement but is not always accurate and if attached to a steep concrete surface, the mesh inhibits good glue contact between the stone and the concrete and is not recommended for vehicular traffic. On flat surfaces there is no problem with the use of the mats.
Once the stones are glued together, grouting can start the next day. The grout can be a simple sand/cement mix with an oxide added for color if desired or a premixed colored grout. Premixed grout is more expensive but requires less labor and is more consistent in color and hardness.
The problem:
Traditionally, the grout is spread into the 10mm gaps with a squeegee or by hand and cleaned with a sponge and water when the grout has partially cured. In a large area, such as a driveway, this is a very slow and tedious process. Granite pavers have a rough surface that is difficult to clean and easily absorbs cement, which can leave stains. These can be cleaned later with hydrochloric acid, but this takes considerable time and risks staining the grout.
Alternatively, the stone can be sealed before grouting with a good quality penetrating stone sealer. This will prevent stains. However, since pavers must be clean and dry before sealing, on large jobs this is not always practical.
The solution:
Faced with these issues, he was convinced that if he could use an extrusion method like a large grout gun to force the mortar into the voids, he could significantly reduce the time on this part of the project.
Some investigation revealed ‘The Pointmaster’, a very simple device consisting of a PVC cylinder with a replaceable stainless steel nozzle and a manual plunger. The Pointmaster was primarily designed for pointing old bricks, but it turned out to be a magical tool for grouting pavers.
Using pre-mixed mortar, fill the cylinder. Being careful not to spill anything, place the nozzle in a gap and slowly squeeze out the grout. It takes some practice (and a strong back) to get a smooth flow.
If you fill the gaps almost to the top, let the mortar set for about 3 hours. It can be smoothed as low as you like to allow the stone to stand taller. For smoothing I use bolts of various sizes or even sticks. It is a simple and quite satisfying process and produces an excellent result.
Tips:
1. Don’t try to smooth the mortar too soon or it will be slow and messy. You should also not leave it on until the next day or it will be very difficult for you to work. What works best is to apply the grout in the morning and let it set and smooth in the late afternoon.
2. Although noisy and annoying, a leaf blower is best for clearing out voids in the stone before grouting and for removing debris when the grout is smoothed.
Happy grouting!
