Because sandstone pavers have begun to be available at more affordable prices, there has been a substantial increase in the number of homeowners using the natural stone in their home improvement projects. There are a number of other reasons for this popularity, including the fact it is slip resistant, cool under foot during even the hottest summers and provides a casual elegant style. When your supposedly quality pavers have begun to deteriorate prematurely, however, it is likely that you will be seeking answers to the problem.
When you first purchase your sandstone pavers the supplier should have given you some information that will help you to care for the material in your chosen location. Usually, this care package provides information on maintenance, cleaning and protecting it through the application of a sealer. In most cases, it has been found that sealers of all kinds are highly beneficial in maintaining and even enhancing the appearance of sandstone. However, in some environments, like pool surrounds, they are found to cause accelerated decay.
- Topical sealers should not be used on sandstone that has been laid in an external location, as these sealers create an impermeable barrier. Whilst this prevents any substance from entering the material, it also prevents them from leaving it. If there is moisture below the pavers, this can cause quite a problem.
- Even though the pavers themselves are relatively impermeable, the joints between them may allow water to seep through to the substrate. The lateral movement of moisture from garden beds or storm water drains can also enter the substrate. If the moisture cannot drain out of the bed, the only way out is up.
- Some pavers will display a large amount of decay around the perimeter, which can be described as ‘picture framing’. This is a sign that moisture has travelled preferentially along the joint between adjoining sandstone tiles and that it has deposited dissolved salts on the surface when it has been evaporated.
The use of the wrong sealer on your sandstone pavers can see each of the above issues result in a variety of forms of decay. When trapped water has no other avenue of escape other than to go up through the stone, for example, any soluble compounds contained in the water will be deposited on the surface, beneath the protective layer. The build up of these compounds can cause delamination (or flaking), which causes pieces of the sandstone to actually break away. This is also known to cause dimensional changes (or expansion).
This is not to say, however, that you shouldn’t seal your sandstone pavers, as this is actually a vital part of keeping them in tiptop condition. Instead, you should make sure that you have chosen a high quality sandstone to use in your project, that you have chosen a sealer that is suitable for the location (impregnating, for example, is a no-no outdoors), that you have a professional install the stone for you and that you apply the sealer as soon as possible. This will make sure that your pavers remain in good condition always.