Before coatings are applied on existing hardscape materials, all old coatings should be removed. Options for doing so range from alkaline-based cleaners to acid washes, which can etch the faces of concrete pavers and any natural stone that is a calcium carbonate such as marble, travertine and limestone. There are specialized cleaners to remove oil and grease, mold, mildew and algae stains, epoxy grout haze and sticky substances such as tar stains, chewing gum, and tree sap.

Though hardscapes don't need near as much TLC as softscapes do, a little maintenance keeps them looking better and lasting longer. This includes cleaning and sealing them as needed, and enhancing them as preferred.

Jennifer Lopez, senior tech service representative, and Diane Phelan, product manager for Laticrete International, the makers of Paver Armor Pro products, lent their expertise to help relate best practices for hardscape maintenance.

Existing Hardscape
If older pavers, wall stone and the like are to be maintained, the first step is determining if they have a coating on them presently.

"Identifying what product is already on the surface will always be key," says Lopez. The types of coatings include topicals, enhancers and penetrating sealers. Topicals enrich the color and add a gloss. Enhancers, like the company's No Gloss Color Enriching Sealer, deepens the color but does not impart a gloss, provides water and oil repellency, and the stability to hold up to UV rays, weathering, etc. Lopez cautions that once applied, enhancers are not easily removed. Sealers preserve the natural look of the stone or pavers while giving them the ability to repel water and oil.

Another chief early step is identifying the type of material you are working with. This has special importance during the cleaning process. When rust or efflorescence salts (white, powdery deposits) are present, the best method of getting rid of the stains is to use an acid wash. However these products can damage some hardscape materials.

 

Penetrating "natural-look' sealers that preserve the physical look of stone or pavers have a fluro chemical that provides oil and water repellency. Generally they last up to three years in exterior applications. These sealers also lock joint sand. They are not intended for use on glazed, polished, or non-absorbing surfaces.




For coatings that change the appearance of the hardscape materials on vertical surfaces, it is advised to start at the bottom and work up, as it is easier to control drip marks. When applying product to both vertical and horizontal surfaces, Jennifer Lopez, a senior tech service representative for Laticrete International, recommends working on the horizontal surface first and letting it cure so any drips from the vertical surface will be easier to remove.

"Any stone that is a calcium carbonate - marble, travertine, limestone - or concrete pavers, are all acid-sensitive," Lopez states and adds that clay pavers are not.

The danger is that the face of the materials can be etched by the acid wash though Lopez admits that many times a material's rough surface hides any etching.

"That is where testing comes into play," as Lopez strongly recommends treating a small inconspicuous area before using any cleaner or coating.

Besides acid washes, other cleansers available include heavy-duty alkaline formulas that clean and degrease masonry surfaces, helping to improve penetration of the coatings.

"It essentially preps the surface for the maximum adhesion for sealing - your next step," says Phelan.

There are also specialized oil and grease removers, mold, mildew and algae stain removers, and heavy-duty coating and finish strippers that also remove epoxy grout haze, and sticky substances such as tar stains, chewing gum, and tree sap.

Directions for use of these products generally involve wearing protective clothing, eyewear and gloves, using a clean, stiff scrub brush, deck brush, or other appropriate equipment, rinsing the area thoroughly with water when done, and allowing the surface to dry.

For the heavy-duty masonry cleaner, and the mold, mildew and algae stain remover it is recommended to pre-wet the intended area with fresh water. Some of the solutions are meant to dwell on the surface for a given time.

For the harsher solutions, a wet/dry vacuum is strongly recommended to remove the cleaner from the surface before rinsing the area with water. And avoid applying these solutions to surfaces not intended to be treated. It is advised to saturate the ground around plants, shrubs and grass with fresh water prior to application and cleanup. For added protection, cover all plants, shrubs and grass and promptly uncover once cleaning is complete.

With the efflorescence and rust remover, a neutralizing rinse, such as the heavy-duty masonry cleaner, may be needed; followed by a fresh water rinse.

The mold, mildew and algae stain remover can be sprayed directly on a soiled area.

"Most of the times you will see algae and mold growing around the planters, and then it spreads to the stone," Lopez discloses.

If one cleansing product does the job, then you can move on to the application of the coating. "If not, you need to take it a step further," says Lopez in advising to use the different products in combination with each other.

To apply the coatings, surfaces must be thoroughly clean and dry although the penetrating sealers may be applied to damp surfaces one hour after standing water has been removed. Avoid applying the coatings in direct sunlight, but surface temperature should be 50???(R)???AE?F to 80???(R)???AE?F. Apply separate coats with a natural bristle paintbrush, paint roller, low-pressure sprayer, or pump-up garden sprayer.

This is an example of bare pavers coated with an enhancer, which can enrich the color of the surface while providing water and oil repellency, protection from UV rays and other weather forces. Of all the types of hardscape coatings, enhancers are the hardest to remove once applied.

Lopez cautions against using sponges and rags, and "High pressure sprayers are not recommended because you tend to overspray."

Allow 30 to 45 minutes between coats or until the surface is dry.

"Most of the products take two to three coats," adds Lopez.

For the topicals, surface traffic may begin 12 hours after final application. The area has to be kept dry for a minimum of 12 hours; full cure is achieved in 24 to 48 hours.

For the sealers, allow each coating to penetrate the surface for 15 to 20 minutes while brooming it into the surface. A full cure is achieved in 24 to 72 hours but use of the area may resume in 6 to 8 hours. If use must resume sooner, cover with red rosin paper. If there is a possibility of rain within the 72-hour cure time, cover the surface so it remains dry.

Lopez suggests a weekly routine of cleaning with a gentler product like their daily masonry cleaner to prevent build up. Its neutral formula will not harm or remove existing sealers, finishes, or waxes.

New Installations
For concrete driveways, Lopez says that the daily masonry cleaner can used first but cautions that, "We don't want to feed too much moisture on to a brand new driveway because you can create efflorescence issues."

Phelan adds, "If you just put the concrete down, you want to make sure that there is no debris on the ground so you can dry sweep."

If the high gloss color enriching sealer is selected, the fresh concrete slab requires a minimum of 28 days to cure before applying the product.

For a new paver patio, "I would just dry brush and then determine if you want to have high gloss, semi-gloss, no-gloss but color enriched, or preserve the natural look," says Lopez. "For sidewalks you want to be more mindful. If you are on the East Coast you do deal with a lot of de-icing salts, so you might want to use the saltwater resistant sealer."

For new installations with grout, the high gloss sealer can be applied as soon as 72 hours after grouting.

Some final application tips involve working on vertical surfaces. For the enhancer and topicals, Lopez suggests starting at the bottom and proceeding up to help limit drip marks.

And what about working on vertical and horizontal surfaces in the same installation?

"My preference would be to do the horizontal first, let that cure out, and then attack the vertical," Lopez says. "But if you do the vertical first, you can do the horizontal the same day."