Liquid Rubber Roof Repair

Surface Preparation:

All surfaces to be coated should be clean and dry. Remove peeling paint and brittle caulking. Heavy build ups of asphalt roof cement should also be removed. Tighten any loose fasteners and replace those which are severely corroded. Repair or replace roof panels damaged by storms. If using this product for metal roof repair, remove heavy rust with abrasive discs or wire brushes. Power wash all surfaces to be coated and allow to dry thoroughly. Caulk all gaps wider than 1/16 inch which are not expansion and contraction slip surfaces.

Treating Rusted Areas:

For metal roof repair, 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.

Going Over Existing Coatings:

[1] Original mill finish
If still tightly adhering, it can be top coated directly with Liquid Rubber. Corrosion inhibitive primer should still be used on severely corroded areas.

[2] Alkyd paints
Aged alkyd paints that were applied over the original mill finish should be checked for adhesion. If coating is brittle and can be scraped off easily, it must be removed before Liquid Rubber can be applied. If removal can be accomplished with high pressure water spray, that should be the method of choice. If removal is spotty, the roof should be allowed to weather another year before removal is again attempted.  Brittle alkyd paint will continue to lose adhesion over time and will result in predictable failure if not removed.

[3] Asphalt based coatings
Liquid Rubber should not be applied directly over an asphalt based coating. Water based acrylic elastomeric coatings may be used as intermediate coats before applying Liquid Rubber. Asphalts should be considered as being unstable materials and are excluded from warranty coverage by Pro Guard Coatings. Caution-Latex house paints can not be substituted in place of the acrylic elastomeric coating.

[4] Acrylic elastomeric coatings
Liquid Rubber bonds very well to these coatings. Some of the earlier acrylic elastomeric formulations were prone to the development of under film corrosion. 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.

The decision of whether to apply Liquid Rubber over an area with severe under film corrosion becomes an economic one. The recommendation should be to replace the corroded panels. However, if this is not an economically viable solution and removal of the coating is equally impractical, then application of the Liquid Rubber may be justified as being the best of the available alternatives. No warranty would apply in such a case.

Application of Liquid Rubber:

Airless or Air Atomized spraying is the only feasible application method for corrugated or standing seam roofs. Airless equipment needs only one hose from pump to gun but must generate 3500-4000 psi pressure and is limited in the length of hose which can be used because of high pressure drops. Air atomized equipment requires two hoses to the gun making it more cumbersome to maneuver plus the addition of a compressor.

Airless equipment specifications: 

Liquid Rubber will produce greater line drops and spray with narrower fan than most other coatings. Some solvent (xylene or mineral spirits) may be used to thin the product to make it spray easier. This dilution should not exceed 2 quarts solvent per 5 gallon pail. The recommended procedure is to spray apply and roll back with a short nap roller to obtain an even film and complete surface coverage. Application should be at rate of 40 square feet per gallon. This will produce a 20 mil dry film. The chemical and physical properties of Liquid Rubber make it possible to achieve a 20 mil dry film on sloped or vertical surfaces with one evenly applied coat.

Spray-on followed by rolling where surfaces configuration permits will produce an even film. Roller marks will level out in a few minutes.

Fasteners:

Caulking around fasteners is usually not necessary. The physical properties of the EPDM rubber [Liquid Rubber] will produce a longer lasting seal around fasteners than caulks can because the latter will brittle with age causing loss of adhesion and cracking.

It is good practice to brush the rubber into the fasteners after spray application to ensure complete coverage. This procedure will still be less time consuming than caulking.

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 reinforcing. Apply a light coat of Liquid Rubber, center the fabric on the overlap and roll it out taking care not to create wrinkles; press fabric down with squeegee or wide spatula; spray apply a full coat of Liquid Rubber to seal top surface of fabric and roll back over to ensure coverage.

Over Spray:

If over spray lands on cars, it can be easily removed with Mineral Spirits within 24 hours. Thereafter, stronger solvents such as Xylene will be effective in removing the rubber but may dull some finishes. Black, one foot square test panels should be placed in various parts of the parking area as evidence of over spray in the event later claims are made.

Flushing Spray Equipment:

Three separate flushes with Xylene are recommended. Save this solvent for future use.

When the last of the Liquid Rubber is sucked from the pail, add several gallons of Xylene to pail to purge material from line and onto roof. Remove gun from the hose and place end of hose in same bucket as pump suction. Reduce pump delivery pressure and allow solvent to re-circulate for five minutes. Remove suction tube from bucket and purge line. Starting with clean solvent or the final flush from a previous cleaning, repeat the procedure two more times.

The gun can be reattached during the final flush for cleaning.

Pail Handling and Disposal:

Pour material from newly mixed pail into the one from which the pump is sucking. Scrape the sides of the just emptied pail into the next one to be mixed. Only a thin film of material should remain. When this procedure is used, the pails can be collapsed and placed in a trash dumpster or taken to a metal recycler.

Rain Showers or Freezing Temperatures.:

Unexpected rain showers after application may affect the surface appearance but will not wash material off roof. Temperature drops below freezing will arrest the cure but will not damage Liquid Rubber. The cure reaction will resume again whenever adequate temperature returns.

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2-Year Warranty

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