Have you ever experienced a soft and flexible roofing surface? Well, that’s polyurethane! It is touted as one of the strongest and most durable coatings by global clients. Polyurethane liquid membrane waterproof coating helps protect substrates from corrosion, abrasion, weathering, and other natural processes.
Some of its benefits are:
⦁ Sustain thermal elasticity
⦁ Inhibit the damaging effects of ponding water
⦁ Impact-resistant
⦁ Optimal for high-traffic areas
⦁ UV-stable
Polyurethane Liquid Membrane Waterproofing – The Optimal Covering for Flat Roofs
The need for a versatile and long-lasting waterproofing solution is growing rapidly. New innovations and techniques, such as nanotechnology are painting an attractive picture for clients and businessmen around the globe. Moreover, self-healing properties are also being added to the liquid membranes or sheets.
Polyurethane liquid coatings, unlike other coatings, are being reinforced with different chemicals and compounds. For example, researchers have developed an anti-corrosion reinforcement (graphene and other materials) for liquid polyurethane; it affects the performance of the membrane favorably.
Polyurethane liquid membrane coatings should be 2mm thick (at most). In addition, it should be applied in 2-3 coats. It is excellent for seamless surfaces, such as floors, basements, and flat roofs. A reliable PU coat possesses the following characteristics:
⦁ Zero Water Swelling Rate
⦁ High Retention of Elasticity and Tensile Strength
⦁ Strong Adhesion
⦁ Restrict Humidity
N.B. The long curing time of polyurethane liquid membranes is a slight disadvantage. However, with strict regulations and rules, the process can be managed.
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Application of Polyurethane Liquid Membrane
⦁ Pitched or flat roofs
⦁ Plaza Decks
⦁ Balconies
⦁ Water Tanks
⦁ Patios
⦁ Industrial Equipment
⦁ Pipelines
How to Apply Polyurethane Coatings on Flat Roofs?
With an average lifespan of 20 years or more, polyurethane liquid membrane coatings are a cut above the rest. Let’s discuss the application process in detail.
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Visual Inspection
A detailed scrutiny of a flat roof is essential for applying liquid membrane polyurethane. All the crevices or holes should be marked for treatment. Moreover, particulates (gravel, pebbles, sand, etc.) need to be removed from the area completely.
Water leakage of any kind should not be present.
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Replace Damaged Materials
If a concrete block is missing, or there’s a broken pipeline, repair or replace it immediately. Also, ensure proper ventilation on the roof.
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Pressure Cleaning
After covering the unwanted spaces, clean the area with high-pressure water and chlorine solution (4.5 gallons of water and 2 quarts of chlorine). The optimal pressure for cleaning a flat roof is 2500 psi. Mildew, mold, algae, grease, and other contaminants are removed easily.
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Repair Surface
A rough patch, pothole, or hairline crack should be mended quickly. Concrete cancer, if present, should be filled with a sealant or grout. Fill low spots to achieve a leveled surface. Ensure that the area is dry and smooth.
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Taping
Cover all seams, crevices, valleys, and fractures on the roof with tape (to restrict water intrusion). Before applying the primer, remove the filters (line and gun).
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Apply Primer
Apply the primer perpendicular to the flat roof at a rate of 100-150 sq. ft. per gallon (if spraying).
Wet film thickness: 12-16 mils
Dry film thickness: 4-7 mils
N.B. Let it dry for at least 4 hours.
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1st Coat of Polyurethane Liquid Membrane
Follow the checkerboard pattern (perpendicular to the roof width) to coat the flat roof.
Wet Film Thickness: 14-16 mils
Dry Film Thickness: 8-10 mils
N.B. Let it dry for 12 hours before applying the second coat.
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2nd Coat of Polyurethane Liquid Membrane
Spray or brush the second coat of polyurethane with the same pattern (perpendicular to the 1st coat).
Wet Film Thickness: 14-16 mils
Dry Film Thickness: 8-10 mils
N.B. Let it dry for 24 hours.
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Evaluate and Maintain
To determine the quality and craftsmanship, evaluate the polyurethane liquid membrane application. Ensure that no area is left untouched (with the primer or paint). Divide the roof into different sections and scrutinize it. Ensure to check the penetration by the dry film thickness gauge.
Once the cover is laid properly, cleaning and maintaining the surface becomes easy. You can use soap and water for a speckless finish.
Polyurethane liquid membrane waterproofing is a reliable way to cover roofs: The top part of your premises is safe from leakage and cracks (if maintained properly). These coatings last for 20 years or more.
If you want to have a detailed inspection, smooth application, and a strict evaluation of your flat roof, contact Waterproofing Experts today!
