In our article on tarmac patching we pointed out that there is no way that a patch will ever be invisible. But there is a way that patches can successfully be hidden, and that’s by putting down a new layer of bitumen or an acrylic coating on top of the whole driveway.
There are many different types of product available. Some are little more than thick paint, while others are a version of tarmac that’s treated with flow agents to allow it to be painted on. The more expensive and more effective products will have agents that will reactivate the existing bitumen in the driveway, so that the new layer bonds with it. The acrylic-based products sit on top of the existing tarmac and seal it.
Limitations of a Cover up
It’s worth pointing out that all the manufacturers of these products stress that they are not a substitute for a complete relaying of a tarmac drive. They are designed to hide stains and patches, and improve the look of an existing tarmac driveway. This means that any major defects need to be patched and cured before applying the new top layer.
The manufacturers also make the point that the new layers will erode after time and require reapplication. How long they will last depends on the integrity of the original tarmac driveway, the type of traffic on the surface, and the amount of effort put into preparing the surface prior to application.
Preparation and Application
Application of these products will differ depending on their composition, so it’s important to follow the manufacturers’ instructions to the letter. They all focus on the importance of preparation though, removing loose grit, debris, moss, lichen and dust, not to mention any weeds that have taken root. If a power washer is used, refer to the product instructions to see whether it requires a damp or dry surface before application.
Most of these products are applied with rollers, but it’s well worth getting long-handled ones to help alleviate any back problems. Brushes can be used for detail areas, such as edges, to make sure coverage is complete. With the thicker bitumen-based products you can patch small cracks and pits by mixing some of the product with a filler, such as dry sand, and pushing it into the defect before applying the main layer.
Drying times are variable with the weather and the type of product but most quote times of up to six hours, so the driveway is ready for use reasonably quickly. You may need or want to apply more than one coat, in which case observe the drying advice for the product very carefully before applying the second one. It might start lifting the first layer if you put the second one on too quickly.
Change of Hue
If you want to change the appearance of your driveway, you can use these products to change the colour. There are really only two choices, black or brick red, and if you apply red over black you will need at least two coats. The manufacturers also point out that the black surface will show through as the red surface wears, so it will need reapplication in time.