How to Properly Apply Post Frame Building Concrete Sealant

Condensation in post frame buildings can be problematic. In order to reduce condensation probabilities, minimizing water vapor sources proves to be paramount. Concrete slabs, especially if no vapor barrier was placed beneath them, are a prime source of water vapor. Proper application of sealant can greatly reduce or eliminate water vapor transmission from slab into the building.

Concrete sealant will make your concrete more resistant to weather exposure, water, grease and oil stains, abrasion and deicing salts. What’s more, they will help to make it easier to clean. But in order for a sealer to work its magic, it must be applied properly. Each step, from surface preparation to choosing right application method for product, will have a big impact on final outcome.

Following are some tips for applying concrete sealer properly. Whichever brand of sealant you use, be sure to follow specific instructions recommended by product manufacturer, since they may differ from general guidelines given here.

When you apply sealer can be important as well. Allow new concrete to cure completely (28 days or more, as recommended). Most sealers must be applied under dry conditions, since applying sealant to damp concrete could cause haziness or loss of adhesion. Air temperatures are also important and should typically be above 50°F during and for 24 hours or more after sealer application. Always allow sealer to dry completely before exposing it to foot or vehicle traffic. Drying times before exposure to heavy traffic can be as long as three days.

Surface preparation before applying a sealant will be extremely important. All oil, grease, stains, dirt, and dust must be removed or they may prevent sealer from adhering properly. Some manufacturers recommend etching surface first with an etching solution to ensure best adhesion.

Two most common methods of applying sealant to concrete surfaces are by roller or sprayer, often depending upon whether choosing a solvent or water based sealer. Always refer to manufacturer’s specific application guidelines.

Regardless of application method always strive for maximum coverage. Typical coverage rate should be 250 to 300 square feet per gallon, depending upon concrete porosity. Most important rule to remember – it’s best to apply two thin coats, making sure sealant doesn’t puddle or form uneven, thick areas. When applying a second coat of sealant, apply it in opposite direction (or perpendicular) to first coat to ensure even coverage. Wait to apply second coat of sealant for 24 hours or time recommended by the manufacturer.