Excerpt from manufacturer’s website
Planning Work on days when rain is not expected, and in temperatures of 65 to 75 F for comfort. The curing process requires an ambient temperature of between 55 and 140 F. Note: The spread rate of 42 to 46 square feet per gallon is for a smooth surface, For a non-smooth surface you need to reduce the spreading rate. This does not include surface preparation time (cleaning the surface). After application, allow another 16 to 20 hours before the surface is dry to the touch and will take foot traffic. Although Liquid Rubber EPDM will immediately waterproof, even while wet, avoid heavy rain until it is dry to the touch (16 to 20 hours after application). Otherwise pitting may occur. A full cure will be achieved in four to 10 days after application in consistent 70-degree ambient temperatures. Higher temperatures will accelerate cure times and lower temperatures will extend cure times.
Surface Preparations After inspection and repair of structural faults and under-skin corrosion, any asphalts or silicone-type of caulking on the roof or surface, should be removed. Asphalt products are not compatible with Liquid Rubber EPDM. Silicone rubber and Liquid Rubber EPDM also will not adhere to each other and shouldnot be used together. Any holes, gaps, seams, tears (of more than 1/16-inch wide) should be repaired or reinforced. Any potential weak areas should be reinforced. Holes and low spots should be filled with non-silicone caulking or epoxies to plug leaks and level low spots. Prior to coating, thoroughly clean and wash the surface with detergent (soap) and water, ensuring the surface is free of oils, dirt, debris and flaking paints, etc. If the surface has fungus, molds, algae or other biologicals, you may need to soak these areas in a 1/3 bleach-and-water solution to kill the biologicals. When applying Liquid Rubber EPDM you will still need to scrub these areas with soap and water use a stiff brush after soaking with the bleach solution, as some biological anchor onto some types of surfaces and must be mechanically removed even after killing. Thoroughly dry the roof prior to applying Liquid Rubber EPDM after cleaning. Unwanted splatters and drippings can be cleaned off with rags and xylene or mineral spirits while wet (within four hours after application). Before applying, mix the pre-measured catalyst by following label directions. A single application is preferable to multiple coats. On flat surfaces, the material can be poured, spread with a squeegee and evened out with a short nap roller. You can also use a paintbrush for small areas such as fishponds, pipes, chimneys and roof flashings. Touch-ups may be applied as desired after the initial film has cured, and the surface is wiped with solvent. The meterial must be applied at a 20 mil layer to ensure its effectiveness. Apply with a brush around flashings and edges using long, slow strokes. The product will level itself when sufficient material has been applied. EPDM Liquid Roof bonds very well to these coatings. Some of the earlier acrylic elastomeric formulations were prone to the development of corrosion beneath the film. There usually is little visual evidence of this on the surface of the acrylic, so small sections of coating must be removed from different parts of the roof to determine whether the condition exists and how severe it is. A visual inspection of the underside of the roof panels can reveal total penetration in the most severe cases. Application of Liquid Rubber EPDM
You will need an electric drill (not cordless), a mixing shaft, a mop-handled rubber squeegee, a mop-handled short nap roller and a paintbrush to apply Liquid Rubber EPDM manually. Use a brush for hard-to-reach areas.
Broadcast and spread using a short nap roller to smooth out trapped air a rubber squeegee to evenly distribute the Liquid Rubber EPDM ( short nap = ¼ inch “) Using long mop-type handles for the squeegee and the roller will allow you to apply the product standing up and not on your knees. Standing up will be much easier.
It is important to apply an even distribution of Liquid Rubber EPDM at the correct thickness. Too little materials will produce too thin a membrane, with inadequate adhesion and inadequate film strengths. Too much material will be wasteful, may cause under-cure or long cure situations, and may cause excessive swelling with some types of sheet-rubber roofs. The optimum thickness for most purposes (non-immersion conditions) is one coat of 20 mils DFT.
A) Clean and prepare the surface to be coated as directed. B) Reinforce with butyl tape and polyester fabric if needed (gaps, tears, seams, pin-holes, defects, etc.) – check with our Technical Service Department for procedures. C) Catalyze and apply Liquid Rubber EPDM to the surface/roof as described, using a squeegee, roller and brush to ensure an even application of 20 mils DFT.
To achieve a 20-mil DFT thickness, you should do a spreading-rate calculation. For fairly smooth surfaces such as EPDM sheets, unpolished metals, fiberglass roofs, etc., use a spreading rate of about 40 square feet per gallon. Reduce this for rougher surfaces such as steel-troweled concrete surfaces, using a spreading rate of about 30 square feet per gallon.
When calculating surface application area, ensure you measure true surface areas. Example: If a panel is corrugated, take into account the corrugations in calculating the surface area of the panel. If you have not applied Liquid Rubber EPDM before, we would recommend you apply it in several pre-measured sections. The first section will give you a feel for the product and how fast you are able to apply it. You can then do larger areas in subsequent sections.
We recommend you apply 2 gallons to the first section over a pre-measured 80 square-foot section, applying the entire 2 gallons.. in an even application and forming a 20-mil DFT thickness when cured. The key is to spread the product evenly – not thick in some sections and thin in others. In 75 to 85 degree temperatures, the product will start to thicken in about four hours, so you should plan your work sections within that four-hour timeframe or less.
The first 2 gallons should not take you more than an hour, maybe two, but this will give you an idea of how fast (or slow) you can work. On subsequent sections, you may choose to apply, say, 5 gallons over 200 square-foot sections if it only took you an hour to do the first 80-square-foot section.
Follow the directions on the cans when ready to apply the first 2 gallons. Run the mixing shaft of an electric drill inside the 2 gallons of Liquid Rubber EPDM (within a larger mixing container) until a vortex forms. Pour the pre-measured catalyst (two bottles) into the vortex and let the drill run for about five minutes to thoroughly mix the Liquid Rubber EPDM with the catalyst. The catalyst is in plastic bottles and is bluish-purple in color. You will be able to see the bluish catalyst mixing into the Liquid Rubber EPDM if it is white.
Pour the catalyzed 2 gallons of Liquid Rubber EPDM onto the pre-measured 80 square-foot area in a serpentine manner. Use the rubber squeegee to quickly spread the product over the 80 square feet as evenly as you can. Again, it is stressed that an even application is important. Do not have certain areas thick and other areas thin.
Use the squeegee to broadcast the Liquid Rubber EPDM quickly. The short nap roller (¼ inches) promotes a more even distribution of product and gets trapped air bubbles out. After spreading with a squeegee, go over this area with the roller in slow, long, even strokes. Let the materials dictate your speed, so the roller does not pull materials along. Make several strokes with the roller to get an even and bubble-free application. Turn the strokes 90 degrees and continue the long, even strokes over the same area. Use a paintbrush for nooks and crannies, and areas where using a roller may be difficult.
You may initially see some roller/brush strokes. Liquid Rubber EPDM, however, is self-leveling and these roller/brush strokes will level off after application.
By applying an even thickness of 2 gallons of Liquid Rubber EPDM on an 80 square -foot pre-measured area, you ensure the correct dry film thickness. When applying the next section, overlap an inch or two and blend in the overlap so you have a continuous and seamless membrane when cured.
After application in 70 degree temperatures, Liquid Rubber EPDM will be dry to the touch within about 16 to 20 hours. It will still not be fully cured, but you will be able to walk on the roof/surface. In these temperatures, your new application of Liquid Roof will be fully cured in about four to ten days. Higher temperatures will accelerate the curing time and lower temperatures will prolong the curing process.
On some materials, such as EPDM rubber sheets, some swelling may occur due to solvent absorptions after applying Liquid Rubber EPDM. This is normal. This swelling will recover (shrink back) with time and heat. In temperatures of 80 degrees or so, allow seven to 14 days to recover. In colder temperatures of 60 F, recovery will take as much as six to eight weeks.
Some adhesives on existing structures (used to bond the rubber sheets to the wood deck/structures) may degrade, or are of a poor quality and may not re-bond to the roof deck when the swelling has recovered. Should this condition occur, you might need to re-bond the sheet rubber onto the roof deck with quality adhesives. As we have no control over the type of adhesives used on existing structures, we cannot be held responsible for such occurrences.
Using Liquid Rubber EPDM too thickly on a single application will also cause excessive swelling and longer recoveries. Thick single-coat applications should be avoided. Overly thick (single-coat) applications will take too long to cure, or may not cure in the center. Application on Plywood and Wood Surfaces It is our recommendation that you first seal all untreated wood and plywood products with an oil-based sealer when applying Liquid Rubber EPDM over non-porous wood and plywood. Porous and unstable substrates will not take application or cure well with Liquid Rubber EPDM . Sealing the wood with a good oil-based sealer will reduce the porosity of the wood and minimize trapped moisture, hence reducing the possibility of rot and generally protecting the wood from degradation. When using an oil-based wood sealer, follow the manufacturer’s directions and the recommended dry/in-service times. Let the oil-based sealer set/dry before applying the Liquid Rubber EPDM coating.
For treated or painted wood, clean the surface with soap and water to rid it of residual oils, debris and dirt. Make sure flaking paints are removed. Make sure the surface is dry before applying Liquid Rubber EPDM, and work on a rain-free day with temperatures above 55 F; however, 65 to 75 F. would be ideal. For smooth surfaces, use 1 gallon for every 40 square feet of area you intend to coat. Reduce this for rougher surfaces. If you are coating larger roofs and structures, you may have several seams and joints. If these gaps are under 1/16 inch, you may coat over them without additional reinforcements or fillings. However, if you expect excessive expansions or movements, or have larger gaps, you should reinforce these seams.
AsphaltBased Coating Application EPDM Liquid Roof / EPDM Liquid Rubber should not be applied directly over an asphalt-based coating. Water-based acrylic elastomeric coatings may be used as intermediate coats before application of EPDM Liquid Roof / EPDM Liquid Rubber. Asphalt-based coatings should be considered unstable and are excluded from warranty coverage. Caution – latex house paints cannot be substituted for the acrylic elastomeric coating. Click Here for Product Information On Our Elastomeric. Adhesion
Adhesion will increase over time. Polar surfaces such as metal, concrete and wood will create stronger adhesion than non-polar surfaces such as asphalt and single-ply EPDM sheet. Most weathered surfaces, including single-ply and thermoplastic membranes, will have enough of a surface profile to anchor the Liquid Rubber.
Durability
By itself, the EPDM Liquid Rubber membrane will exhibit the characteristics of its EPDM chemistry, i.e., UV and ozone stability, excellent resistance to ponding water, and long-term retention of flexibility. However, since it is always applied to an existing surface, the condition of that surface will determine overall life expectancy. Do not apply Liquid Roof over cream-color ALPHA rubber. EPDM Liquid Rubber applied over generally sound single-ply EPDM can extend the life of the single-ply EPDM another 20 years. The useful life of metal roofs also benefits greatly when EPDM Liquid Roof is applied. BUR systems often have existing problems such as delamination between layers, buckling and stress cracking. These are further aggravated by wet insulation, which often results in severe corrosion and weakening of the metal supporting deck. Projecting a life expectancy for the EPDM Liquid Rubber membrane ultimately comes down to a case-by-case determination. When the EPDM membrane is compared to urethanes, acrylics and other elastomers in accelerated weathering and heat aging tests, the EPDM shows itself to be superior.
Surface Preparation
EPDM Liquid Roof / EPDM Liquid Rubber – Liquid Rubber may be applied to roof decks, gutters, structural steel, air-conditioner enclosures, metal roof leaks, RV roof leaks, cooling towers, galvanized steel, unit-heater flues, smoke stacks and chimneys, fiberglass, and non-porous masonry surfaces. 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.
All surfaces to be coated should be clean and dry. Remove peeling paint and brittle caulking. Heavy buildups of asphalt roof cement should also be removed. Tighten any loose fasteners and replace those that are severely corroded. Repair or replace roof panels damaged by storms. Remove heavy rust with abrasive discs or wire brushes. Power=wash all surfaces to be coated and allow them to dry thoroughly. Caulk all gaps wider than 1/16 inch that are not expansion- and contraction-slip surfaces.
Remove loose portions of existing coatings and brittle caulk with a 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 recoated. Asphalt-based aluminum coatings should be removed as much as possible by wire brush or abrasive disc. Roof cement should be removed and replaced with butyl caulk where necessary.
Repair torn rubber by re-gluing loose areas with contact cement. Coat exposed edges with contact cement to prevent solvent absorption from EPDM Liquid Roof / EPDM Liquid Rubber. A rubber patch may be applied over the torn area if desired. Remove chalk from the white rubber membrane by brushing it with a detergent solution, followed by a water rinse or a working of the surface with a stiff brush. Smooth metal or plastic surfaces should be roughed up to improve adhesion of EPDM Liquid Roof / EPDM Liquid Rubber. A deglossing solvent may work on some plastics.
EPDM Application for Large Commercial Projects
Airless or air-atomized spraying. Airless equipment needs only one hose from pump to gun, but it must generate pressures of 3,500 to 4,000 psi, and only a limited length of hose can be used because of 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. For commercial implementation CLICK HERE.
Equipment Specifications
PUMP – capable of delivering 3to 4 gallons per minute at 3,500to 4,000 psi HOSE if 3/8-inch ID max. Permissible length is 150 feet when using .019 tip if 1/2-inch ID maximum. Permissible length is 200 feet when using .21 tip.
Temperature and Cure Conditions
The outside temperature needs to be at least 55 degrees for cure (drying) to take place when you apply Liquid Roof; however, night temperatures or temperature drops will not affect the product. It simply will not cure until the temperature reaches 55 degrees. EPDM Liquid Roof / EPDM Liquid Rubber can be applied at any temperature that permits its being spread onto the surface. It will waterproof immediately upon application. The solvent will evaporate at a rate governed by temperature, but will not be affected by relative humidity. Exposure to freezing temperatures before cure has taken place will not damage the films. The time necessary to reach cure should not be a concern, as this process will occur automatically. Exposure to sunlight will accelerate the curing process. The final film properties of the cured membrane will be the same regardless of the time required to achieve cure. EPDM Liquid Roof / EPDM Liquid Rubber will provide long-term protection even under extreme exposure conditions. Please read all safety precautions and heed all warnings. EPDM Liquid Roof / EPDM Liquid Rubber will waterproof immediately upon application.
Application on Rusted Areas
It is recommended that a corrosion-inhibitive primer first be applied to areas where severe rusting has occurred. Liquid Rubber does not contain any corrosion-inhibiting pigments, but it is such an effective moisture barrier that it may be directly applied over light rust without a primer.
Fasteners
Caulking around fasteners is usually not necessary. The physical properties of EPDM Liquid Roof / EPDM Liquid Rubber will produce a longer-lasting seal around fasteners than caulks can because the latter will embrittle with age, causing loss of adhesion and cracking.
Fabric Reinforcing of Seams and Overlaps
Tight overlaps and standing seam joints do not need to be reinforced. Overlaps with gaps greater than 1/16 inch and corroded edges should receive fabric reinforcement. Apply a light coat of EPDM Liquid Roof / EPDM Liquid Rubber, center the fabric on the overlap, and roll it out, taking care not to create wrinkles; press the fabric down with a squeegee or wide spatula; spray-apply a full coat of Liquid Roof / Liquid Rubber to seal the top surface of the fabric; and roll back over to ensure coverage.
Mixing Directions
Proper incorporation and thorough mixing of the catalyst is critical to achieving desired cured-film properties and should, therefore, be done with great care. The container is under-filled to allow room for mixing as well as the addition of the catalyst. Insert mixing paddle into Liquid Rubber and mix for approximately two to three minutes so the material is moving uniformly and has formed a vortex. Slowly add catalyst into this vortex at a rate that allows it to be incorporated without puddling.
DO NOT pour catalyst on top of Liquid Rubber / Liquid Roof before starting mixer.
After all the catalyst has been added, the mixer (if handheld) should be moved in a circular fashion around the periphery of the pail, as well as up and down, to insure the catalyst is completely and uniformly mixed. Periodically scrape the sides with a rubber or metal spatula to incorporate the stagnant layer of material that adheres to the walls of the pail.
Recoating Liquid Roof
Since Liquid Roof cures by chemical reaction, a single heavy application will be preferable to multiple thin coats. A second coat will bond to a previous film, but that bond will not be as strong as the internal bond within each layer. If a second coat is applied before the first has thoroughly cured, some wrinkling may result as the first coat absorbs solvent and swells. This wrinkling will, however, recover as the solvent evaporates. It is generally recommended that only a single coat be applied over non-porous surfaces, the thickness of which can be varied as desired. Thicker films will take longer to cure through.
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