A 5-MINUTE LESSON ON TOPICAL AND PENETRATING SEALERS
Sealer. It’s probably the scariest product a hardscaper encounters. While there are many different types available on the market, information and general education on application and usage proves to be quite limited (and often conflicting!). Unfortunately, making a mistake on a sealing job is costly and very labor-intense to fix. So it’s critical to choose the right product for each application and apply it precisely as specified by the manufacturer.
In this blog post, we’re starting with the basics and giving you a five minute lesson on topical (film-forming) and penetrating (non-film-forming) sealers. Let’s get started!
Topical (film-forming) Sealer
The bulk of sealers on the market are topical, or film-forming, sealers. These products are available in both water-based and solvent-based options and “can produce sheens of varying intensities that highlight the beauty of a surface and often enhance its color.” (Concrete Decor, 2011).
Need a quick rundown on solvent-based vs. water-based sealers? Click here.
Two of the most common types of topical sealers for hardscape applications are acrylics and polyurethanes or urethanes.
- Acrylics are an economical and effective choice for sealing pavers. They’re generally easy to apply and provide excellent gloss and color enhancement. (Solvent-based acrylics will typically provide more color enhancement than water-based products.) A downside to acrylics is they are very moisture sensitive so weather conditions must be optimal during the time of application. Some acrylic products may also be susceptible to scratching. Solvent-based acrylics are relatively easy to touch-up whereas water-based are a bit more challenging but can still be touched-up.
- Polyurethanes or urethanes are ideal for sealing but typically expensive and slightly more difficult to apply than acrylics. They come in single component (aka 1K: ready to pour, no additional components needed) or two components (aka 2K: carrier needs to be mixed with an activator or catalyst component). It’s important to note that 2K products can be tricky to mix and have a limited pot life once mixed. Water-based polyurethanes are tougher than acrylics as well as more UV and chemical resistant.
Penetrating (non-film-forming) Sealer
If your goal is to provide an invisible layer of protection against stains and de-icing salt damage, a penetrating sealer is the right option for you. Penetrating sealers work by increasing surface tension to cause beading. These products will create hydrophobic water-shedding, meaning water will quickly form into droplets on the sealed concrete paver surface instead of soaking in. While penetrating sealers will not provide color or sheen enhancement, they offer superior levels of abrasion, heat, and UV resistance.
The most common types of penetrating sealers are silanes, siloxanes and fluoropolymers.
- Silanes work their way deep into a concrete paver and essentially clot the pores of a concrete surface. These products will only wear away if the concrete surface itself wears away. They are most commonly used for sealing dense concrete.
- Siloxanes work very much like silanes and will clot the pores of a concrete surface. Siloxanes have larger particle sizes than silanes and likely won’t penetrate as deeply. These products are generally only used on fully cured existing concrete.
- Fluoropolymers are expensive but they’re easy to apply and long-lasting. These sealers offer a superior level of stain resistance and lifespan compared to other penetrating sealers.
So which one is right for your project? ForConstructionPros.com has put together a great list of factors to consider before making a decision:
- Customer preference/requests
- Environment - (indoor/outdoor, ambient temperature, weather conditions, etc.)
- Level of maintenance
- Environmental/governmental requirements
- Time between resealing
- Final color
- Ease of application
- How consistent the sealer is across the application
- How the sealer cures