No concrete installation is complete without the application of the correct sealer. Taking the time to put down this final layer of protection not only prolongs the life of your concrete but can also enhance and preserve its appearance.
The benefits, depending on the product used, include:
- Enriching the colour intensity of the concrete
- Adding sheen to the surface ranging from satin to high gloss
- Blocking the penetration of dirt, oil, grease, chemicals, and stains, making the concrete easier to clean and maintain
- Inhibiting efflorescence or dusting of the surface
- Preventing the intrusion of water and chlorides
- Protecting against abrasion and wear
To obtain all these advantages you must choose the right sealer for the job. You’ll find many products on the market to suit just about every type of concrete application, but no one sealer is perfect for all projects. Even worse, using the wrong sealer or applying it improperly can ruin an otherwise flawless concrete installation.
To help you sort through the options and avoid making mistakes you’ll regret later, here’s an overview of the basic types of sealers available, followed by a list of questions to ask when shopping around for the best product for your needs.
How much concrete sealer do I need?
Once you single out the right sealer for your needs, the next step is to decide how much to buy. Generally, coverage rates for sealers are calculated by square footage.
For example, the technical data sheet for the sealer you plan to use says the product has a coverage rate of approximately 100m2 per 20L. Take the overall square footage of your project and divide it by the coverage rate.
If you want to save money buy in 20L rather than 4L containers, a larger size is usually cheaper. Or better yet, try Barefoot Concrete’s concentrated sealers, they are often much more economical and having some extra on hand to reseal is always good.
For example, if an average coverage rate from trade supply store product is 100m2 per 20L, then Barefoot Concrete’s concentrated waterbased sealers are up to 450m2 per 20L, a significant benefit.
Is the sealer compatible with the surface treatment you’re applying?
Always check with the sealer manufacturer to verify the compatibility of its product with the surface you plan to put it on.
Some sealers may interact with certain overlays or colouring agents, resulting in unwanted side effects such as blistering, bubbling, delamination or bleeding of colour.
If you plan to apply a sealer to a concrete coating or topping, we recommend checking with the concrete resurfacing product manufacturer for recommendations as to the appropriate sealer to use. Or better yet, take the “systems approach” and select the sealer the decorative concrete resurfacing manufacturer sells specifically for use with its products.
Does the VOC content of the sealer meet local regulations?
If you plan to use a solvent-based sealer, be sure to check the volatile organic compound or VOC content of the product to make sure it doesn’t exceed acceptable levels in your area.
The federal or state government may have mandated certain maximum allowable levels of volatile VOCs that concrete sealers are permitted to contain. Certain states default to the federal mandates while some set their own.
Not all solvent-based sealers contain the same amount of VOCs. For example, xylene is a common solvent found in concrete sealers and produces VOCs, while acetone, another common solvent found in concrete sealers, is considered an exempt solvent and produces no VOCs.
Another key factor is the solids content of the product. The higher the solids content, the lower the liquid solvent and VOC content. You can find out the solids and VOC content for a sealer by looking at the Material Safety Data Sheet (MSDS) or specification sheet for the product.
Barefoot Concrete products have very high solids content ranging from 46 -54% depending on the product. Choosing a high solids content gives you additional benefits for the experienced applicator.
What conditions will the sealer be exposed to?
To keep maintenance to a minimum, it’s important to select a sealer that will protect your concrete or decorative concrete coating from the traffic conditions and elements to which it will be exposed. A concrete resurfacing solution has the best protection with a good quality purpose-driven sealer.
For example, for a stamped concrete driveway, you’ll need a sealer that repels oil and grease stains, prevents penetration of water and chemicals, and resists abrasion.
The primary type of sealer used for exterior concrete is a solvent or water-based acrylic. If you don’t want a sheen on the surface and prefer a natural look, a penetrating sealer like W881 Sealer, B883 Sealer or G887 Natural Stone Sealer is an alternative that provides excellent protection against outdoor exposure conditions.
For an epoxy flake floor, a high-build sealer with good resistance to scuffs and staining, such as a polyurethane or epoxy, will generally provide the best protection and be easier to maintain.
On indoor surfaces, softer acrylic sealers usually require regular maintenance with several coats of a sacrificial floor finish, or wax, to prevent wear and black heel marks.
Is the sealer breathable?
This is a really important point, especially for decorative concrete resurfacing as you want to allow water vapour to pass through but not water. One of the reasons acrylic sealers are commonly used for exterior applications is because they are “breathable,” they provide good water repellence while allowing moisture vapour within the slab to escape. Most penetrating sealers are also breathable.
Epoxies offer excellent water repellence, but some products are impermeable and can end up trapping moisture in the concrete. This would be a problem for concrete resurfacing and will increase the risk of the coating delaminating.
If you suspect that excess moisture is present in the slab, do a moisture test, whether indoors or out, and make sure the sealer you use is permeable and won’t restrict the ability of the concrete to release moisture vapour as needed.
How long will the concrete sealer take to dry?
How soon a sealer can be recoated or opened to traffic may be critical on fast-track projects. Acrylic sealers dry the fastest, setting to the touch within 30 to 60 minutes after application and ready for light traffic as soon as 12 hours after the final coat, depending on air temperature, humidity levels, and other environmental conditions.
Polyurethanes and epoxies typically require longer curing times of at least 24 hours.
Waterbased sealers also require 24 hours and best to keep foot traffic off the sealer to allow the sealer to cure.
Is the product safe to apply indoors?
When working indoors, it’s usually safer to use a water-based rather than solvent-based product, especially if the area can’t be ventilated. Solvent-based sealers are extremely flammable and the fumes they emit can be hazardous to your health and the health of children and pets.
What type of finish and surface appearance do you want to achieve?
If you’re after a wet look to enhance the appearance of coloured finishes, choose a sealer with a medium to a high-gloss sheen. Most acrylic sealers are available in a range of sheen levels.
Solvent-based acrylics generally enhance colour better than water-based products. For an additional colour boost, you can even create colour washes with some acrylic sealers by mixing in powdered or liquid tints.
For applications where a shiny or wet look is not desirable, you can also find film-forming sealers with matte or low-gloss finishes. There are even “flattening agents” available that can be mixed into some sealers to control the level of gloss. Another option is to use a penetrating sealer that won’t leave a surface film.
In high-traffic areas, the slip resistance of a sealer may also be important. For these surfaces, look for a sealer that exceeds slip-resistance requirements.
What Is the life expectancy of the sealer, and does the manufacturer provide a warranty?
The life expectancy of a sealer depends, in part, on exposure conditions and how well the sealer is maintained. In general, however, epoxies and urethanes deliver the best long-term performance and can last years before the need for reapplication.
Some manufacturers may even provide a warranty to back the performance claims for their products. However, this warranty will be null and void if you don’t adhere to the manufacturer’s guidelines when applying the sealer.
Notice that cost is not one of the key considerations listed here. Certainly, you should compare the prices of similar products to get the best value, but don’t try to cut cost corners. Sealer is too important to the overall appearance and longevity of your work.
Plus, you don’t want to give your clients a protective finish that will wear away after only a year or so.
Barefoot Concrete focuses on quality products, as when it comes to sealers, therefore, you get what you pay for. Don’t go cheap, you will pay for it in the long run. Call us to find out more about our high-quality concentrated sealers.
Article adapted from the Concrete Network.