Masonry & Stucco Surfaces

When prepping stucco and masonry surfaces for sealing, experts say contractors must remember the fundamentals: know the substrate you’re dealing with, the look you want to achieve, and the pros and cons of the various products on the market.

One mistake many contractors make is rushing into a sealing project without a thorough inspection. Martin Welsh, director of product services at Duron, which makes DURA Crete products, says contractors sometimes work backward. They picture the end product first and forge ahead to match that picture in their mind. Instead, contractors should first understand the substrate they’re working with, and then adjust their thinking accordingly.

“If you walk around the project a couple of times and really review and evaluate the conditions you’re dealing with before you jump into it, you’ll be better prepared,” he advises.

Before you begin
Water is the biggest enemy of stucco and masonry; whether it’s in liquid or vapor form, it’s at the root of most failures, says Michele Margotta Neary of UGL (United Gilsonite Laboratories) of Scranton, Penn.

Water can cause a variety of problems for masonry surfaces: cracking and chipping; changing the alkaline nature of the concrete, which can allow rust on rebar and steel supports; etching caused by acid rain; and more. The surface must be repaired before the new sealer is applied.

Problems to look for before starting the job, according to UGL:

• Cracks in foundation walls — Cracks are usually a sure sign that water has become trapped around the foundation, perhaps due to improper drainage or faulty downspouts.
• Spalling — In cold climates, spalling can be a big problem. If water enters the pores of a brick wall and freezes, the expansion of the ice crystals can create so much pressure that the face of the brick seems to pop off.
• Efflorescence — The white, powdery deposits come from calcium and magnesium salts found in brick and mortar. Water intrusion can dissolve the salts, which rise to the surface and leave their telltale chalky residue behind. Efflorescence is often found on the inside of masonry walls and places where deteriorated chimneys, faulty gutters or moisture adjacent to the foundation allows water to enter the bricks.
• Rising damp — If the groundwater table is high and the soil is constantly wet, brick walls can suck up water, almost like a sponge, damaging masonry units.
• Stress cracks — Walls expand and contract in heat and cold. These stresses can produce long, vertical cracks.

Know your products
Once the contractor has a good feel for the problems that must be fixed and the look he or she wants to achieve, the next step is to understand the range of products that are available.

Steven Roemheld from ABR Products of Franklin, Wis., says this step is absolutely critical. “This is something that should be tattooed on your power washer, or your palm: Before beginning the overall operation, test to determine product suitability: Is this product going to give me the desired end result?” Also, test for the proper dilution ratio and understand how many times the product has to be applied.

Don’t think of the job as cleaning and sealing, think of it as restoring and preserving, he says.