100% Silicone Skylight Coating

SC 32.20 is a high solids, low VOC, 100% silicone translucent skylight coating designed to waterproof skylights while still allowing natural light into the building.

Available in 1 gallon and 5 gallon buckets.

1 gallon of this product can coat 67 square feet; 5 gallons can coat 333 square feet.

SKU: HS3220 Category:

Basic Uses & Description:

Home-Sil SC 32.20 Series Skylight Coating is a silicone roof coating made of one component. It is moisture curing silicone rubber roof coating system designed for use on existing fiberglass skylights.

The system provides long-term protection because it resists weathering, aging, oxidation, wind-driven sand, rain and snow, the effects of ozone, UV radiation and the temperature extremes typically found on roofs.  Home-Sil SC 32.20 Series Skylight Coating can be applied in very thick coats without blistering, and still maintains maximum adhesion.  Home-Sil SC 32.20 Series Skylight Coating is only available in clear.

Composition and Materials:

Home-Sil SC 32.20 Series Skylight Coating is a dispersion of silicone rubber.  This coating is one-part and is ready-to-use out of the bucket. It can be applied easily to a dry, frost-free surface, and cures at normal temperature in 1 to 4 hours by reacting with moisture in the air.  Cure time will be lengthened in areas with lower than normal humidity levels.


Home-Sil SC 32.20 Series Skylight Coating is available in 1 gallon and 5 gallon buckets.

1. Use power washer to clean roof surface.
2. Remove all debris and loose particles.

1. Ensure surface is completely clean and dry.
2. Install 1.5 gallons of silicone coating/ 100 sq. ft. of surface (15 mils) over skylight surface with a medium nap roller or brush.
3. Allow material to dry for at least 24 hours.
4. Install second, identical coat of silicone coating to 15 mils, for a total thickness of 30 mils.

What coverage rate should I use for RC 32.20?
The recommended coating thickness is 30 mils, or 3.0 gallons/100 sq. ft. This coat is achieved through two applications of 15 mils.

How much acrylic coating do I need for the same job?
This answer varies greatly depending on the substrate being coated, but a good estimate is twice as much acrylic as silicone for the same job. Acrylic requires a primer coat, a base coat, and one to two top coats at 1 gallon/100 sq. ft. That adds up fast!

How does this material compare to acrylic caulking sealants?
Silicone is superior to acrylic in four key ways. 1) Prep times are much greater for acrylic, and once installed they can take up to 80x longer to cure than silicone. 2) Water based vs. Silicone based. Acrylic coatings are water based, and therefore they cannot resist the elements and ponding water like silicone can. 3) Wash-off is a problem for acrylics. They are an evaporative cure product, and run a high risk of wash off shortly after installation. Silicone does not face this same problem because it is moisture-curing. 4) Silicone is the lowest VOC roofing product on the market, 4-8 times less than acrylic VOC content. Silicone lasts longer, and never needs to be replaced, only reapplied. That longer life-cycle leads to a much lower environmental impact. Check out our blog post here for a more thorough explanation of each factor above.

How do I know if I need a primer?
Our coating adheres to most substrates without a primer. If you have a fiberglass skylight, you do not need a primer. If you have skylights other than fiberglass, contact your Progressive Materials representative to find out if you need a primer.

What substrates can I use this material on without a primer?
This coating is designed for fiberglass skylights. It can be used in other applications, but is only guaranteed for its intended use.

How should I apply this material?
Our coating can be spray-applied or rolled on. The roller should be nap resistant. See our spray guide for specific requirements for the sprayer.

What colors is this material available in?
Our skylight coating is translucent to allow natural light into the building.

What is the skin on top of the material?
This skin is the result of the coating beginning to cure in the pail. Silicone is moisture-cured, so high heat and humidity will cause the product to skin. If surface skins, remove skinned material from container. To minimize skinning over several days, pour a thin layer of 100% mineral spirits on top of product until it is completely covered and do not move pail until ready to reuse. When ready, stir thoroughly with a power mixer. Keep container tightly closed between applications to minimize surface skinning.

Is there a mildicide in this material?
There is no mildicide in our roof coating because mildew does not grow on the surface of our silicone products. Unlike acrylic coatings, our coatings are inert and do not provide a food source for mildew or mold.

Can I pressure wash this product?
All of our products can be pressure washed at a low power setting (<2,500 psi) once installed and cured.

Does this product have a UL approval rating?
All of our products are UL rated when installed on a non-combustible surface.

Can this product be used on a peaked roof?
Our roof coatings have been specially formulated to decrease “run-off” once applied. This means that, yes; our products can be applied to peaked roofs and still maintain their integrity.

Since both coats are the same color, how can I see where to apply the second coat?
Chalk lines may be used to distinguish where you will start and stop, but most skylights are small enough that this won’t be necessary.

How should I clean up afterwards?
Use normal precautions to avoid getting the product on your skin (wear long pants, socks, long sleeves, and work gloves). If you do get product on your skin, you can scrub it off with soap and water. Product will not come out of clothing or shoes. Clean tools after application with 100% mineral spirits and a rag.

How should I dispose of this product when finished?
Consult your districts policies on disposal of silicone. All of our products are inert and therefore will not cause any issues when disposed, but you should follow your district’s policies.

How do I check that I am applying at the correct coverage rate?
We have mil gauges available to check your coverage thickness while you are working.

How long should the material sit before being walked on?
Most of our products cure in less than 24 hours, but to be safe you should wait 24 hours before walking or placing equipment on the freshly applied product. This rule also applies to adding a second coat.

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