Sealing in Natural stone: Understanding the different stone sealers
Aesthetically pleasing, and touted to last a lifetime, more people are installing pavers onto their patios, driveways, walkways, gardens, and swimming pool areas. They are also easy to live with, requiring very little in terms of both cleaning and maintenance. To get the best out of your pavers, you are advised to give them some form of protection from damage. One way to shelter them from spills and the elements is to apply a seal.
Sealing is the covering of the surface of the pavers with treatment that is meant to arrest staining, corrosion, erosion, and other forms of damage. This damage mainly comes from normal household activities that can cause spills, scratches, and nicks to the stone. Food spills, for instance, can cause staining due do acidic compounds in certain items like tomatoes, sauces, and wine. Nicks, on the other hand, may come from moving furniture, and normal household traffic.
Fun fact: Granite needs to be sealed too. There is a misconception that granite is durable and does not need care. While it is a superior material when it comes to withstanding most things, it can still be eroded over time, either by the elements or by man-made factors.
A stone sealer should not be confused with a stone enhancer. Although the latter is also applied to the stone, it does not have any protective properties against staining. Its main purpose is to highlight the natural colors in the stone, giving it a deeper richer look. It is important to note that some sealing products contain both a sealer and an enhancer.
What type of sealer is the best for you?
There are two types of stone sealers in the market, topical and penetrating (sometimes called impregnator). The choice largely depends on the type of stone you have, where it is installed, and how it is used. If you are unsure about the stone, you can gauge the porosity with a simple test. This is done by pouring a few drops of water in the paver and observing the amount of time it takes to seep completely through. If the water disappears in under a minute, the stone is very porous. The longer it takes to vanish, the less porous the stone. This is will matter because topical sealers work with porous stones such as limestone and slate while penetrating sealers works with less porous stones such as granite and marble.
This is a sealer for natural stone usually has either urethane or acrylic as the active ingredient, and creates a protective layer against damage from water and oil. It produces a characteristic glossy finish on the pavers, making them look polished. They also make the pavers slippery when wet, and may require either a non-slip additive or a mat. This type of sealer may darken the surface of your stone and alter the pavers’ natural look.
Topical sealers have two major drawbacks, with the first being their tendency to show scuff marks and scratches. This is something to note if you plan on applying it on your patio, where you are likely to move furniture. The second disadvantage is that they tend to wear out quickly especially in areas that have a lot of traffic and require to be reapplied more frequently, as much as every six months in some cases. The re-application process is tedious and comprises stripping the older veneer and reapplying a new coat. They also involve more maintenance in terms of cleaning.
This sealer works by protecting the pavers from underneath. It penetrates the stone and repels oils and water from beneath the surface. The main selling point is that it does not alter the appearance of the pavers in any way. It can, however, be paired with an enhancer to improve the facade of the pavers. Penetrative sealers are breathable and keep the oils and water from damaging the stone, without trapping moisture in the interior. This is important if your pavers will be exposed to the elements for long periods. If water is trapped inside the pavers, any changes in the weather could cause freezing and thawing and this strain causes the pavers to crack.
Another big selling point for impregnators is longevity. It takes a longer time between the reapplication of the sealer because it takes longer to wear off. Since it works from beneath the surface of the stone, it does not get scrapped or abused by traffic and can, therefore, last longer.
It is important to note that penetrative sealers do not protect the surface of the stone from scratches. It will also require a special kind of cleaner, which can be an added cost.
What you need to know
Depending on the type of sealer, you will typically be expected to reapply every 6 months to 3 years for it to work as expected. Some other factors will influence that time frame as well. These include:
The porosity of the stone: This will not only determine the amount of sealer used, but also the time it takes to wear out. This is because porous rocks absorb more water and oils and at a faster rate, which gives the sealer a heavier workload.
The amount of traffic: Sealers used in high traffic areas will need to be reapplied sooner. This is because there is a higher likelihood of spills from foodstuff, and scratches from the movement of people and furniture. Table and chair legs, mobile grills, and high heels are particular culprits.
How often you clean: The amount of cleaning you do will also affect the longevity of your sealer. This is because the stone will regularly interact with water (The element the sealer protects the stone against), causing it to wear out faster. Hard brooms and brushes may also cause scuff marks.
The type of sealer: The type of sealer you used the last time out will dictate how quickly you need to carry out another treatment. This also ties in with the brand used, since different manufacturers will offer different lengths between applications.