Liquid EPDM Rubber and Liquid Roof Application
For a complete list of suggested application click here. If you have any of the following roof types, you will first need to apply a coat of the proflex primer which is available here.
Preparation. Although light rain can directly touch Liquid EPDM before it has cured, we suggest that you plan a day when rain is not in the forecast. Liquid Roof may be applied at any temperature, but we suggest between 55°-80° for comfort. Liquid Rubber needs 55° for the product to cure. Many people have asked us if they can apply it below that temperature. The answer is of course, YES, but the curing process won’t continue until it gets above 55°. Assuming you have a smooth surface that needs to be coated, the coverage per gallon is approximately 42 square feet. For rough substrates, the coverage is 30 feet per gallon. An example of a rough substrate is plywood or troweled concrete. After you have completed the application, we suggest waiting approximately 48 to 72 hours before walking on the surface. It will develop a skin within 12 hours. Note that it may take up to seven days for a full cure to result. For any separation in the joints we suggest filling them with the Rutex caulk found on or order form. This Caulk has been field tested and is compatible with the liquid epdm and will not void its warranty. It is free of any solvents or isocyanates and is 100% volume solids. More information can be found HERE (RUBEX CAULK)
Once your roof inspection is complete and any structural issues have been repaired, you also want to be sure that any silicone, tar or asphalt-based materials are removed as best as possible. You will need to prime those areas first with the ProFlex Primer which can be found on our order form. Remember that the primer is only needed for asphalt based products and elastomeric. Any rips in the seams or spacing more than 1/15 of an inch, and we suggest reinforcing them with either poly-fabric or the butyl two-sided tape. Both are available on our order form. Any holes, gaps, seams or tears (of more than 1/16-inch wide) should be repaired or reinforced. Rusted areas on your metal roof need to be brushed with a wire brush to get as much of the oxidized off as possible Any corrosion that is not loose is fine to apply the liquid epdm over. In the event your roof is tar or asphalt based you will need to apply a coating of the ProFlex primer to allow for an acceptable substrate for the liquid epdm rubber to adhere to. If someone has previously applied a roof cement or any silicone caulking it will need to be removed and replaced with a butly type caulk or acrylic. Before applying the product, ensure that the surface is clean from any debris that might be picked up in the application with the roller. We suggest a mild detergent washing with Simple Green or something similar. This will minimize the oils, dirt and debris that was present. If you have any mold or mildew that has built up on the surface, we suggest first washing those areas with a 1/3 bleach to water ratio. Be sure that the surface of the roof is perfectly dry before applying the Liquid Roof. Liquid EPDM will not adhere to moist or damp surfaces. Particularly on those summer mornings, let the dew dry. Keep some Xylene or basic mineral spirits on hand just in case you get the Liquid Rubber on unwanted areas. For more on mixing instructions, watch the video below.
This is a true one-coat application. There is no need for a second coat. However, if you want to apply it a little thicker, we suggest doing that on the first coat as opposed to a second coat. Pour the material onto flat surfaces and then spread with a squeegee. Reapply over the areas with a short nap roller 1/4 inch thick. You want to be sure you apply the material at 20 mil, which is about the depth of 5 or 6 pieces of paper. You can go to a local paint store and get a mil gauge, which is a metal wheel with notches cut out of it and showing the different mil rates. Simply dip the gauge into the wet surface and read it. You want to be sure to have an even distribution of Liquid Rubber. Not applying enough will result in a thin membrane and will lead to inadequate adhesion and weak film strengths. Over-applying is wasteful and may cause under-cure or long cure times. Also, one common byproduct of over application is excessive swelling with some types of sheet-rubber roofs.
Surface to be coated should be clean, dry and structurally sound. Fasten loose areas with adhesive (contact cement) or pop rivets. Oil or wax MUST be completely removed with solvent otherwise the product may swell and wrinkle and will not be covered under warranty. We suggest applying one coat of the ProFlex Primer in the event you feel any oils or waxes cannot be removed. Remove loose portions of existing coatings and brittle caulk with scraper and wire brush. Whatever still has good adhesion may remain to be recoated. Rusty or pitted metal should be wire brushed to remove loose oxide. Tightly adhering corrosion may be directly coated with Liquid Roof®.
Liquid EPDM Rubber Mixing and Characteristics
One of the more popular characteristics of the Liquid EPDM Rubber is that it self-levels as the proper mill rate is achieved is applied versus the competition, where this needs to be addressed during the application.
If you view the mixing video on this page you will see that an electric drill and a mixing shaft are needed, which are available on our order form for purchase. A rubber squeegee and 3.8 inch nap or med. Nap roller are also required.
The short nap roller will smooth out any trapped air. The squeegee is used to evenly distribute the Liquid Rubber EPDM. Get a squeegee and a roller with a long handle to alleviate your need to do the entire project on your knees. Standing up will be much easier.
When determining your overall square footage (surface area), be sure to measure the true area. For example, assume that you have a metal corrugated roof. You need to look at the square footage of the raised areas of the roof and add that to your total square footage. If this is your first time applying Liquid Rubber EPDM, we suggest you chalk your roof off into either 42 sq. ft. or 210 sq. ft. sections. When you are done filling in the area you should be done with either that gallon or five gallon pail. This is how you know you are applying it at the recommended spread rate.
We will use an example of 2 gallons for the remainder of this section. Image you just received two gallons and will be applying them to the first section - a pre-measured, 80 sq. ft. section. The key is to spread the product evenly because you don’t want it too thick in some areas and too thin in other parts of the roof. Next, let’s discuss curing temperature. In warm climates where daytime temps are in the 70s or 80s, Liquid EPDM will begin curing in four hours, so plan your sections knowing that you have 4 hours to work with the product before it starts its initial setup.
The application of the initial two gallons should not take your more than one hour, so you have plenty of time to do the job right. This will give you an idea of the pace of your work.
You want to mix the Liquid Rubber EPDM until a vortex is created. Five minutes is sufficient mixing time. You will notice the catalyst in plastic bottles is a different color. Don’t worry; it will not affect the color of the material after it is mixed thoroughly.
Note: the product will take light foot traffic after it is fully cured for workers to be able to get on the roof for inspections air conditioning work etc.
Applying EPDM Liquid Rubber
Here is what you will need:
- Electric drill (cordless drills will be effective)
- A mixer for a can or pail.(paddle mixer) available on our order form
- A rubber squeegee attached to a broom handle.
- One Short nap roller approx. 1/4” attached to a broom handle.
- Paint brush
- Rubber spatula
- Mineral spirits or Xylene for clean up
- Bag of Rags
When using the broom handles it will allow you to apply the product standing up vs having to get on your knees. The paintbrush is for the corners and hard to reach sections. Broadcast the material in a letter “S” manner and then spread it using the squeegee. Follow up with the ¼” nap roller to smoothen any trapped air and equitably distribute the EPDM Liquid Rubber®. Any mistakes such as drips or platters should be cleaned off with rags. The Xylene and/or mineral spirits should only be used on the Liquid EPDM when it is still wet not to exceed 4 hours after application.
Apply the Liquid EPDM
Now you are ready to begin. There is no need to wait for the product once it is mixed. Pour the two gallons of Liquid Rubber EPDM onto the pre-measured 80 sq. ft.area. Use the rubber squeegee to quickly spread the product over the area as evenly as you can. Remember that an even application is important. Make sure that some areas are not thicker than others
Use the squeegee again for broadcasting the Liquid Rubber EPDM quickly and use the short nap roller to achieve even distribution and to release the trapped air bubbles. Let the materials choose your application speed so the roller doesn’t pull materials along. Make several strokes with the roller to get an even and bubble-free application.
You may initially see some roller/brush strokes. After a few minutes, it will change to form a smooth seamless membrane.
Liquid Rubber EPDM will be somewhat tacky for 12 hours. It will still not be fully cured, but you will be able to walk on the roof/surface within three days. Assuming temperatures are above 70° a full cure can be expected in 5 to 10 days. Higher temperatures will decrease the curing time and lower temperatures will increase the time. If the temperature falls below 55° take that into account.
When handing certain substrates like EPDM rubber sheets, you may see some lifting or swelling. This is a result of the solvent being absorbed into the Liquid EPDM. This is normal, and the swelling will shrink back given time and temperature. If this has occurred, it is simply an aesthetics issue. In temperatures of 80° or above, allow seven to 14 days for recovery. In temperatures of 60°, it could take up to six weeks.
Liquid EPDM on Plywood and Wood Surfaces
When working with any wood application you first want to seal it with the ProFlex Primer. Porous and unstable substrates will not accept the application and will result in an ineffective cure. When working with applications over existing painted wood, clean the surface with soap and water to rid it of residual oils, debris and dirt. Scrape off any flaking areas. If you have washed the roof, ensure that enough days have passed so that any water absorbed into the wood has evaporated. When working with large commercial roofing applications, inspect the joints and seams. If there are any gaps 1/16 inch or larger, you will need reinforcement or filling. Wood application are not covered by warranty as it is impossible to verify the condition of the wood i.e. rotten wood or wood that has absorbed water.
EPDM Liquid Roof/EPDM Liquid Rubber cannot be applied directly to these surfaces. Any of the above, as well as any third party coatings that you are not sure of, must be coated first with the ProFlex Primer. This will ensure a stable substrate for the Liquid EPDM rubber.
Strength and Durability
EPDM Liquid Rubber will demonstrate all of the chemical characteristics that have made it so successful. UV and ozone stability, excellent resistance to ponding water, and long-term retention of significant temperature changes are all benefits. It is always applied to an existing surface, so the current condition of the surface will have a factor in determining the overall life of the roof. However, a realistic expectation is 14-15 years before a recoat is needed.A caution about ALPHA rubber. Some manufacturers use “Alpha brand rubber” such as Fleetwood. Refer to your owners manuel or contact them directly. If you do have an Aphla roof you will need the ProFlex Primer
Spraying Liquid EPDM Rubber
There are more details on spraying in our brochure, which can be printed from our website. Airless equipment needs only one hose from pump to gun, but it must generate pressures of 3,500 to 4,000 psi, and specific hose length needs to be used due high pressure drops. Air-atomized equipment requires two hoses to the gun, making it more cumbersome to maneuver. It also requires the addition of a compressor.
PUMP is capable of delivering three to four gallons per minute at 3,500 to 4,000 psi HOSE if 3/8-inch ID max. Permissible length is 150 feet when using a .019 tip if 1/2-inch ID maximum. Permissible length is 200 feet when using a .21 tip.
Recoating Liquid Roof
Liquid Roof dries (cures) through a chemical process, and a single heavy application is better than multiple thin coats. A second application will certainly adhere to the first coat, but the bond will not be as strong. If your second coat is applied before the first has dried, some wrinkling may result due to the absorption of the solvent. This wrinkling will reduce over time as the solvent evaporates from below. Should you have any questions about your particular application, you can call our Sales staff at 855-281-0940 (ext 2).