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Now that you are finished designing and gathering tools, the next step is LAYERS.

This blog the third of a series of blogs designed for do-it-yourselfers. This series features step-by-step instructions for building your own heated driveway or patio using brick pavers. The process for building a non-heated driveway is the same (just omit install of heating cables).

Layers. All paving is made up of multiple layers that improve the structural quality of the paving.

Sub-grade is the first layer – the bare raw earth. You will need to reduce the sub-grade to formation level, in other words dig down. As you reduce the layer, keep in mind that you are creating a space deep enough to accommodate not only the brick pavers, but the sub-base as well. Make sure the formation level is as even as possible, removing all high spots and low spots until it mimics the profile of the proposed driveway/patio/pathway. Check for any soft spots that need to be excavated and filled with the harder clay based soil of the formation level.

At this point in the process, many people choose to put down a geotextile separation membrane. This layer has many different names but the goal of the layer is the same: to keep the sub-grade and sub-base layers from mixing and creating settlement. However, a geotextile layer is not needed for every job. If you live in an area with a sub-grade that is dry and firm, you can omit the geotextile layer with a minimal risk of mixing between layers. For sub-grades that are anything less than dry and firm, a geotextile layer can dramatically improve the performance of the completed project. So what is a geotextile layer? Surprisingly, it’s a simple sheet of non-woven fabric.

After the sub-grade layer comes the sub-base.  The sub-base provides flexibility between the sub-grade layer and the base. Although you may not always need a sub-base layer for all patio projects, it is an essential layer in the creation of driveway paving. The biggest cause of settlement and shifting of the base layer is a non-existent or unsatisfactory sub-base layer. Most residential building projects require an unbound sub-base layer such as crushed rock or recycled crushed cement (versus cement-bound and bitumen-bound sub-bases).  The goal is a mixture of larger particles and fine particles (sand) that creates a firm void-free layer.

After spreading the sub-base layer, level it out using spades and finish off with a rake. Next use the vibrating plate compactor to compact the layer and eliminate as many voids as possible.  The sub-grade layer should be between 100-200mm in depth (after the compacting process). To achieve a depth of 150mm, a safe rule of thumb is spreading 200mm depth of non-compacted sub-grade. After the compacting process, the depth will be reduced to 150mm.