A New Roof for a Fraction of the Cost!

Pella Elastomeric Liquid Rubber Seam Compound and Roof Coating products seal leaks, protect your roof, and prevent further deterioration of your roofing membrane.
Pella Roof Coatings Elastomeric Liquid Rubber Installed - Seals Roof Penetrations on Commercial Roofs
Liquid Rubber Roof Coating

PRC550 – Pella Elastomeric Liquid Rubber Roof Coating

Seal leaks, protect your roof, and prevent further deterioration of your roofing membrane with the application of Pella Elastomeric Liquid Rubber. A unique, fluid-applied SEBS roof coating, Pella Elastomeric Liquid Rubber is easy to apply, has a Class A fire rating, and provides a strong yet flexible membrane that boasts long-term ultraviolet protection. Guard your assets against roof leaks and deterioration with Pella Elastomeric Liquid Rubber Roof Coating.

PRC500 – Pella Premium Seam Compound

Check out PRC500-Pella Premium Seam Compound for when thicker material is required—pinholes, screw heads, seams, around HVAC installs. Used as a t-sealer or filler.

Specifically Formulated for:

Two-Pass Roof Applications—

  • Metal Roofs and Buildings
  • Modified and BUR Roofs
  • Aged TPO
  • EPDM
  • Storage Buildings
  • Grain Bins
  • Mobile Homes
  • Machine Sheds
  • Storage Sheds
  • Waterproofing around Solar Panel Installs

Easy Application. Roll-on or brush-on.

Acceptable roof types for Pella Elastomeric Liquid Rubber

  • Various metal roofing systems
  • Weathered aluminum
  • Weathered copper
  • Fiberglass
  • Acrylic sheet & any acrylic based products
  • Weathered Vinyl
  • Polyurethane foam
  • Roofs that were coated with a prior roof coating, must be adhering well to roof substrate *not recommended for use over silicone

Pella Elastomeric Liquid Rubber Roof Coating Gallery

Conforms to any shape surface, flashing protrusion, vertical or horizontal, and can be applied easily with a paintbrush or roller. What makes Elastomeric Liquid Rubber unique is that it is solvent-based and cures by chemical reaction. It will form a self-leveling, seamless membrane as it dries. Other coatings dry quickly, leaving air trapped between the coating and the surface, allowing it to crack after years. With elastomeric liquid rubber, the solvent will chemically cross-link and fuse itself to the substrate, allowing for years and years of performance, even under the most trying conditions.

Pella Elastomeric Liquid Rubber is a versatile coating for a broad range of applications. Its superior protective quality is derived from a unique combination of physical and chemical properties. Its chemistry provides extended durability, water resistance, broad temperature tolerance, and chemical and mold resistance. Elastomeric liquid rubber forms a flexible membrane up to 30 mils thick with one coat. The environment can vary from humidity to total immersion. It withstands constant or cyclic temperature changes from -40°F to 200°F. It resists corrosive environments. Elastomeric liquid rubber is an extremely effective corrosion-preventing coating for steel and metal. It does not contain any leachable or sacrificial components, so protection does not diminish over time.

Key Benefits

  • No primer needed
  • Indefinite pot life (with lid secured)
  • 1-year shelf-life
  • Will take standing water 365 days/year
  • ASTM Tested
  • Energy Star approved formulas
  • Proven to outlast standard roof coatings 4x longer
  • Elastomeric liquid rubber forms a seamless membrane
  • Will reduce dirt accumulation
  • Reduces mold and mildew (contains mildewcide)
  • Conforms to any shape or protrusion
  • Reduces heat buildup and noise
  • Easy application
  • Will withstand significant temperature swings
  • Waterproofs within a couple hours of application

Pella Elastomeric Liquid Rubber can be applied to a variety of roofing materials without the need for a primer

  • Fiberglass
  • Elastomerics, or acrylics (not aluminum coatings)
  • Various Metal Roofing Systems
    • Weatherized Galvanized Steel
    • Weatherized Aluminum
    • Weatherized Copper
  • EPDM—Flash coat needed
  • Polyurethane foam
  • Mod bit-hot mop
  • Concrete
  • Hypalon
  • PVC, if over 20 years old

Cure Mechanism

The elastomeric rubber cross-linking takes place at ambient temperatures. Free radicals resulting from the decomposition of solvent cause cross-linking to take place. The rate at which the solvent decomposes determines the rate at which the system will cure. This rate is governed by the temperature and the availability of oxygen. Oxygen is necessary to activate the solvent which promotes peroxide decomposition. The cure mechanism in Elastomeric Liquid Rubber will vary from active to inactive as determined by temperature. Faster cures and slower cures over extended periods of time result in identical physical properties. Broad day-night temperature swings in spring and fall will not compromise the final results of the elastomeric liquid rubber membrane.


Work on days when rain is not expected and temperatures are above 50°. The product begins curing above 50°F. The temperature can go lower during the night with no effect on performance. The product will simply not continue to dry until it gets above 50° again during the day. Bear in mind, the application surface must be completely dry so as to not trap moisture between the surface and coating. Wiping the surface dry is not enough—you will want the surface to be as dry as possible. The product needs a couple of hours for it to waterproof, but after that, light rain will not affect the product. Simply wait for the rain to evaporate to continue the project. The higher the temperature, the quicker the product will dry.

Pre-application of Roof/Surface to be coated

Inspect your roof or surface for structural damage, tears, leaks, gaps, corrosion, etc. Light surface corrosion for adhering can either be lightly sanded or left alone. Heavily rusted areas need a rust inhibitor prior to application. With heavy leaks, inspect the wood deck (or roof structure) for structural damage (rot). Any coatings, including butyl liquid rubber, will not fix structural damage. Any structural fault should be repaired first. Under-skin corrosion may be caused by trapped moisture between the skin and structure, degradation of glues to bond the skin and the roof deck, or a combination of these.

Outstanding Application Characteristics

  • Extremely high resistance to water penetration
  • Ultraviolet and ozone stable
  • Built-in mildewcide
  • Excellent long-term aging properties
  • Extremely broad temperature tolerance range (from -40°F to 200°F)
  • Acid and alkali resistant
  • Excellent in salt-water environments
  •  Withstands ponding water 365 days/year

Application Characteristics

The curing process of elastomeric liquid rubber gives it outstanding surface wetting properties. The product will fill the smallest cracks and irregularities. This enables it to be applied in a single coat over non-porous surfaces, and still result in complete film integrity. Elastomeric Liquid Rubber can withstand water immersion within the first few hours of its cure cycle. Elastomeric Liquid Rubber should not be used where the material does not have exposure to oxygen such as between two impervious materials. When oxygen is available, curing takes place from both top and bottom of the film. There is sufficient oxygen available on most surfaces to initiate cure from the bottom. Oxygen readily penetrates films 20mil thick. Elastomeric Liquid Rubber is extremely easy to work with and, unlike other catalyzed products, as long as the lid is on tight, the product does not cure. This means no loss of materials if you get into a bind on the roof due to unforeseen interruptions.

Commercial & Industrial Applications

Steel siding for buildings

Elastomeric Liquid Rubber is an excellent recoating product for roll-formed steel siding, which tends to corrode at the bends. The rubber can be applied as a one-coat system with no corrosion inhibitive primer needed.

Fabricated steel in marine environments

Cranes, tanks, and support structures at dock facilities experience accelerated corrosion rates due to saltwater exposure. Elastomeric liquid rubber is not affected by salt and is ideal for this type of environment.

Steel storage tanks

Elevated, or on ground surfaces, steel storage tanks can be effectively protected with a rubber coating. Surface condensation, cathodic protection, and thermal stresses between sunny and shady areas don’t cause problems for the coating.

Manual Application Procedures

Elastomeric liquid rubber can be applied directly on many different surfaces with solid, stable, nonporous, and uniform surfaces like flat roofs. For most surfaces, primers are not necessary. Types of surfaces that can be coated with Pella Elastomeric Liquid Rubber are:

EPDM rubber sheets, roofs-galvanized steel panels, roofs-non-polished aluminum sheets, roof-steel plates (painted, unfinished, light corrosion), fiberglass panels, non-porous, steel troweled concrete surfaces, masonry.

Although elastomeric liquid rubber can be applied using airless spray equipment, most of our clients only consider spraying if the surface area exceeds 10,000 sq. ft. Otherwise, the recommended application is a brush or roller. For corrugated roofs, we have special rollers to fit the profile of your roof. In addition, we offer spreaders for larger projects.

Surface Preparation

After inspecting and repairing structural faults and under skin corrosion, any silicone type of caulking on the roof surface should be removed. Silicone is not compatible with elastomeric liquid rubber.

Any holes, gaps, seams, or tears (of more than 1/16″ wide) must be repaired or reinforced. Any potential weak areas must be reinforced. Holes and low spots must be filled with non-silicone caulking or epoxies. Before coating, clean and wash the surface with detergent (soap) and water, ensuring that surface is free of oils, dirt, debris, and flaking paints.

If the surface has fungus, molds, algae, or other biologicals, soak these areas in one-third bleach and water solutions to kill the biologicals. Let it soak until the solution evaporates. You will still need to scrub (with a stiff brush) these areas with soap and water after soaking with the bleach solution, as some biologicals anchor onto certain types of surfaces and must be mechanically removed even after killing.

Thoroughly dry the roof before applying elastomeric liquid rubber. Unwanted splatters and drippings can be removed with rags and xylene or mineral spirits when wet (within 20 minutes after application). Use a short nap roller and a chip brush to apply elastomeric liquid rubber manually. Use a brush for hard-to-reach areas.

Broadcast and spread using a short nap roller to release trapped air and rubber squeegee to evenly distribute the elastomeric liquid rubber. Using a squeegee with a long mop-type handle and roller will allow you to apply the product standing and not on your knees.

It is important to apply an even distribution of elastomeric liquid rubber at the correct thickness. Too little material will produce too thin of a membrane, with inadequate adhesion and inadequate film strengths. Too much material will be wasteful, may cause under-cure situations/long cure situations ad may cause excessive swelling with some types of sheet rubber roofs.

The optimum thickness for most purposes (non-immersion conditions) is two coats at 16mils.

  1. Clean with Pella Super Clean Degreaser/Cleaner and prepare the surface to be coated as directed.
  2. Reinforce with seam tape & fabric mesh, if needed (gaps, tears, seams, pin-holes, defects, etc.) Check with our Technical Service Department for procedures.
  3. Apply elastomeric liquid rubber on surface/roof as described, and use as a squeegee, roller, and brush to ensure an even application of 10-mils. To achieve a 10-mil thickness, conduct a spreading rate calculation. For fairly smooth surfaces, such as EPDM sheets, unpolished metals, fiberglass roofs, etc., use a spreading rate of about 100 sq. ft. per gallon. Reduce this for rougher surfaces, e.g., steel troweled concrete surfaces, and use a spreading rate of about 50 sq. ft. per gallon.

Surface Area

When calculating the applied surface area, ensure you measure true surface areas. For example, if a panel is corrugated, take into account the corrugations when calculating the surface area of the panel. If you have not applied elastomeric liquid rubber before, apply it in several premeasured sections. The first section will give you a feel for the product and how quickly you are able to apply it. You can then do larger areas in subsequent sections.

We recommend you apply 1 gallon at first, over a pre-measured 100 sq. ft. section. When applied evenly, you will form a 10 mil. thickness after it’s cured. Spread the product evenly—not thick in some sections and thin in others. In 65°F to 85°F, the product will start to thicken in about four hours. Plan your work sections within a four hour time frame or less.

Corrosive Environments

Corrosive environments are created by many industrial operations where acids are used. Similar conditions can also be produced organically in poultry and hog production operations, which generate high volumes of manure. Coatings can protect steel and other construction materials from rapid deterioration in these environments.

One component thermoset. Non-thermoplastic materials, regardless of shape, can now be coated with butyl liquid rubber as protection against corrosion or chemical attacks. The coating can be applied by spray, roll-on or brush-on methods.

Reinforce seams, cracks, and defects with seam tape and fabric mesh, following the instructions below:

  1. Clean and prepare the surface to be coated as directed on the label.
  2. Cut a strip of seam tape to cover and bridge cracks, holes, and defects.
  3. Lay the seam tape flat on the surface and use a hard roller to flatten the kinks out.
  4. The seam tape has adhesive surfaces on both sides and will hold the fabric mesh in place. Flatten the fabric mesh with a hard roller as necessary.
  5. Saturate the fabric mesh with Premium Seam Compound or Elastomeric Liquid Rubber to reinforce bridge and ensure bond with surface, tape/mesh, and top. After curing, this section will be reinforced by the Premium Seam Compound.

Easy to Apply:

  1. Surface must be clean.
    Use Pella Roof Coating Degreaser/Cleaner to prepare the surface as needed.
    Brush or spray off any dirt, debris, and rust chips.
  2. Before applying first coat, ensure the surface is completely dry. No water or moisture residue should be present as this will cause the coating to blister.
  3. Apply 2 even coats of product, approximately 10 mils per coat. Allow 2–4 hrs for the first coat to dry before applying the second coat.
    For EPDM and RV roofs, apply a light skim coat before applying a second coat.


For Best Results:

  • Apply coating in temperatures of 50–100°F.
  • 10mils per coat, two coats required. Approximately 1 gallon per 100 square feet at 10mils thick.
  • Roll-on, brush-on for small projects.
  • The spray-on coating requires coating material temperatures of 60°F.

For Top Coat Application Procedures

  1. Mix the product for approximately 3–4 minutes. In the event you have to stop the job for the day, simply put the lid on securely so air will not get in. This will stop the curing process.
  2. Apply masking tape to the perimeter of the roof or wherever straight edges are desired. The tape can also act as a catch basin for sags if only one edge is attached to the roof and the rest is formed into the shape of a gutter.
  3. We suggest chalking off the roof in 20×10 ft. areas or 200 sq. ft. When you are done applying the product in that area, you should have used up a four-gallon pail. Pour some material onto the roof. Follow with the roller to even out the wet film. The product will self-level. Use a brush around vents, A/C pipes, ladders, and antennas. Brush and roller marks will disappear when sufficient material is applied. Work from front to rear.
  4. Masking tape should be left on until the rubber is solid enough to be touched.

To Stop Leaks

  1. Use a wire brush to clean edge-strip, seams and flashings. Use sharp edged spatula to remove cracked or brittle caulk. Rough up smooth surfaces with sand paper.
  2. Apply masking tape when a straight edge is desired, leaving 1½” on either side of the seam for coating.
  3. Apply one coat of butyl liquid rubber with a brush on all seams, flashings, and remaining caulk.
  4. Remove masking tape the following day after rubber has undergone a partial cure.

To Repair Cracks

  1. Trim ragged edges of damage.
  2. Cut new aluminum plate to overlap damaged area by 3″.
  3. Secure plate with rivets or fasteners.
  4. Apply PRC500 Pella Premium Seam Compound with 2″ overlap on either side of seam.
  5. Apply PRC550 Pella Elastomeric Liquid Rubber top coat.

To Repair Rips & Tears

  1. Trim ragged edges of damage.
  2. Cut new aluminum plate to overlap damaged area by 3″.
  3. Drill rivet holes ½” from edge 1½” apart.
  4. Remove plate and apply rubber over holes.
  5. Pop rivet plate and coat with butyl liquid rubber.