Concrete Roof Repair

Concrete flat roofs are porous and prone to hairline cracks. Moisure in the concrete roof slab can corrode rebars and cause structural damage.

Why Consider a Concrete Roof Coating Application?

Concrete roofs are excellent heat batteries. The absorbed heat can take up to 4 hours to dissipate. Elastomeric coatings can reflect up to 90% of the heat and help reduce cooling costs.

BEFORE: This reinforced concrete roof has roof leaks in several locations. The concrete roof already had a thin cementitious type of waterproofing material installed but it wasn’t working very well. It is not a dark colored roof but it gets pretty hot in the summer. The owners were unable to locate the source of the leaks so they decided to apply a seamless elastomeric membrane on the entire concrete roof.

Concrete Roof Restoration Process

• Cleaning and Surface Preparation – The entire concrete roof was thoroughly washed using a 3,000 psi pressure washer. A biodegradeable degreaser was used to ensure a clean surface. All seams, flashings and penetrations were carefully sealed to render the roof watertight.
• Priming – Priming ensures a good adhesion between the concrete roof surface and the elastomeric coating.
• Top Coating – 30 dry mils of elastomeric roof coating is applied on the entire concrete roof in 2 coats.

AFTER: A leak-free, seamless roofing membrane now covers the concrete roof. The cool roof coating reflects about 90% of the heat from the sun. It looks brand new but performs better than new.

Since the building has concrete exterior walls, they were coated with elastomeric coatings too.

Don’t Put It Off Any Longer.

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Roof Restoration Tools

Pressure Washer

A pressure washer is mandatory for preparing a roof’s surface for coating application. Pressure washing removes embedded dirt, chalking and poorly adhered material. In most cases, 2000 psi can adequately clean the surface without damaging adhered roofing laps, masonry or flashings. Higher pressure ratings can speed up cleaning provided that a wider nozzle is used to prevent damage to the existing substrate.

Clear-rinsing detergents may be used to improve cleaning. Be aware of any local restrictions regarding how the wash-off water must be treated or released into storm sewers or swales.

Airless Sprayer

An airless sprayer pump capable of developing 1,800 to 2,500 psi(pounds per square inch) material output pressure should be sufficient to spray a variety of acrylic coatings. A siphon hose on the material inlet typically is used to draw material directly from 5-gallon pails or 55-gallon barrels.

A spray gun with an extender wand allows for comfortable coating application without having to hold the spray gun uncomfortably close to the surface. A 517 tip is usually recommended for roof primers and 631 for elastomeric coatings.

Tips are reversible for easy cleaning and clearing of occasional tip clogs.

Proper spray technique involves keeping a gun level with a roof’s surface at all times, maintaining a consistent distance between the spray tip and surface. Use a overlapping, crosshatch pattern to ensure complete coverage and a uniform finish.