Aug 2019 HOW TO INSTALL CONCRETE PAVING SLAB
From larger square slabs to round or decorative stepping stones, Sephaku Cement shares best practice on how to fit precast concrete slabs of any size, shape or form. With most precast concrete slabs measuring around 50mm in thickness, precast pavers are an ideal option for garden or pavement (sidewalk) pathways, while also offering an easy to install solution for Do-It-Yourself home improvement enthusiasts.
When placing concrete slabs fit for pedestrian foot traffic or the occasional light vehicle traffic, preparing the pavers bed and foundation is the most critical step in the installation process. By ensuring a levelled and compacted stable surface for the concrete slab pavers to anchor to will ensure a lasting installation that remains steadfast and firm under foot.
Taking care to also seal and maintain concrete pavers on location sees concrete slabs offer an effective decorative paving solution, to garden landscaping and pavement exteriors suited to any design theme.
- Placing Concrete Slab Pavers on Garden SoilEnsuring that the sub soil is stable and densely compacted, concrete pavers will need to sit on soil that won’t collapse under pressure or expand when exposed to water, causing the pavers to shift up or down. Poor load bearing soil or any clay soil will need to be cleared away and replaced with a more sturdy soil or stone, taking into account correct depth of both the bed as well as measured to fit the thickness of the slab.Once a bed of stable sub soil has been smoothed over and compacted for added strength, cover the surface with a 25mm layer of fine river sand blended with around 10% of general purpose cement such as Sephaku 32 or Sephaku 42N.
- Placing the Concrete SlabsNow that the sub soil has been adequately prepared, pave the surface with the concrete slabs testing the even placement of each slab as they are moved into place. You can test the stability or “level” of the paver by pressing on the opposite sides of the slab, measuring the amount of movement with your hands. The goal here is for a minimal see-saw effect. You may also like to use masonry string or fishing line to guide your paver’s placement, depending on the design, which will help to create a uniform and neat end result. Also take into account that you will need to leave join spacing of 10 to 20 mm between each slab which will later be filled with a grout mix. As a final step to ensure the level stability of each paver as well as fixing any spacing issues, gently tap each concrete slab with a rubber mallet confirming that each is neat and consistently placed on the sub soil bed.
- Grout the GapsUsing a dry mix of cement and fine river sand similar to the blend placed on the sub soil, measure 1 part of general purpose cement to 3 parts sand, blending well and ensuring the cement is mixed throughout. Neatly fill the joints between each concrete slab with the blended cement sand mix, working this in between all the spaces. After brushing over the pavers and then firmly securing the grout gaps with a brick joining tool, remove excess grouting material to reveal a uniform surface, grouted to perfection. Finish by cleaning each cement slab with clean water and a sponge removing cement residue that you don’t want to cure to the surface later. Finally, coat with a cement sealant that will help prevent future staining and hard to remove blemishes while adding traction to the surface.