Mortar Techniques for Block Paving

When laying a block paving driveway or path you need to decide what way to fill the joins between each block. Essentially there are three methods: Loose Fill, Slurry and jointing with mortar. This last method, where mortar is applied directly into the gaps between the blocks of the paving, will be explored in this article.

Reasons for Proper Jointing of Paving

Jointing with mortar requires time and precision if it is to look good. The technique is effectively the same as grouting tiles in interior decorating; a mortar for the correct strength and consistency is pressed into the gaps and the excess cleaned off. If you're unsure of the right mix to prepare, buy pre-prepared cement-based mortar.

This process, known as striking, helps water run off and prevents frost damage by creating a good seal between blocks or stones. It is very similar to pointing of vertical brickwork and serves a similar purpose. Studies have also shown that the process of striking is that it helps the mortar to become harder as it sets.

Different Mortar Application Methods

There are two methods of laying the mortar into the gaps, one is by hand, using trowels and other hand tools, the other is injecting it in with a gun. With both methods it's important to clean up any mortar that spreads over onto the surrounding blocks as it will stain.

You can mask up the blocks if you are lacking in confidence in this area. Either use thin plywood or cardboard to lay above the edges of the joint, or you can buy commercial masks to lay down over the joint before trowelling the mortar in.

Hand Jointing Paving

The hand method is more laborious. Cement mix is pressed into the joints using an ordinary trowel and then finished off by striking, drawing a pointing trowel or bar along the joint to smooth it and remove excess.

Mortar Application Using a Gun

If you are using a gun, the process is similar but a lot quicker. The gun is the same as those used for mastic, silicone sealants and the like that have become ubiquitous over the last 30 years. Reusable cartridges are supplies that can be filled with mortar, which is then squeezed out into the joint while the gun is moved slowly and carefully along the joint line. For more information, read our article Joint Block Paving With A Gun.

It is still important to follow along the joints, striking as you go. Leaving the mortar as it is after applying it with a gun will not look good and not protect the paving from rain and frost.

Take Care at All Stages

It should go without saying that whatever methods are used to lay the mortar and finish off the joints, the pointing will only look as good as the gaps it is filling. Make sure that attention is paid when the stones or blocks are laid so that gaps are uniform and straight.

Jointing will not be successful if it is used as a means to cover up bad workmanship.