Brush-in Driveway Jointing With Polymeric Resin Mortars

In this blog I’ll show you one of the easiest ways to finish a driveway, and also one of the most effective – brush-in polymeric resin mortar. You can get the polymeric resin mortars in two different consistencies – one is thinned with water so that it flows out of a brush, and this is ideal for applying around small joints in paving bricks; the other is thicker and ideal for larger joints.

There are many different ways of grouting or jointing the gaps between paving blocks or flags on a driveway. One relatively new but very easy method is brush-in granular filling where the granules are coated with a resin. These help the granules bind with each other and with the sides of the paving, and products like this are often referred to by the generic name ‘polymeric’.

Different Brush-in Products

We have already covered brush-in mortars in Loose Jointing for Block Driveways and the application methods aren’t dissimilar. The polymeric resin-based products will last longer though, because the bonding properties of the resin keeps the jointing together better than an ordinary loose fill.

Brush-in polymeric products are quick and easy to lay and make sense for less-uniform flags, where to accurately trowel in mortar would take forever and probably not look particularly good either. They are only suitable for lightly used private driveways, though.

Get the Right Polymeric Product

It is absolutely vital to understand that the application guidelines here are just that, guidelines. It is imperative to read the instructions for any polymeric resin-based product you buy and follow them to the letter.

You must take care to choose the right product for your driveway, too. There are many different manufacturers and brands, and you need to make sure the product you choose will do the job. You need to gauge the width and depth of the gaps you have, and compare them with the specifications of the product. If you use the wrong polymeric, it will not bind properly and will be washed away as easily as small grains of gravel.

Tools and Equipment

The only tools you need are brooms and brushes, hence the name ‘brush-in’. A stiff broom is used to sweep the polymeric grains across the driveway surface and the softer one to sweep the excess off later. A large squeegee, by which we mean one that’s about three feet long and attached to a broom handle, is useful for the spreading, but by no means absolutely necessary.

As soon as you open the containers of polymeric to the open air they start curing so you have to work fast. Most have a workable life of 10 to 20 minutes, so don’t open any containers until you are ready to use them. Use the stiff broom, or squeegee if you have one, to sweep the polymeric across the driveway.

Clearing Up After Polymeric Jointing

There’s no need to tamp the material down into the cracks, as it should settle in by itself. Once you’ve swept the granules into the joints over the whole driveway, go back over it to see if any joints need topping up. Then get on with sweeping the excess off the faces of the paving before it cures.

Most products will start to harden after half an hour, give or take 10 or 20 minutes, depending on the product and the weather conditions. After about half a day they should be able to be walked on, but leave at least a full day before driving on them.


In conclusion, preparation is the key to success with brush-in polymeric jointing. If you take your time and do it right, then you will never need to do the job again, probably for as long as you own the house. But if you rush and don’t prepare properly, then all that effort could be for nothing – just a waste of money.

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