Single Component Solvented Coating Application
- After the tape installation, including coating where required, apply base coat in the specified coverage. Stir all coatings before use. All specified quantities are minimum and are on an undiluted basis. The number of coats is not usually specified and will depend on the slope, drying conditions and other job conditions. Single-component solvented coatings produce a better film with less entrapped air when the rate of application is one gallon per 100 sq. ft. (3.78 L / 9.3 m²) (16 mils (.41 mm) wet). This is the recommended rate. The specified gallonage and uniformity of application are the critical elements.
- Most specifications require alternating colors when several base coats are used. The final base coat should be a color with the least contrast with the specified top or trowel coat color. For white or light topcoats, gray is the preferred final base coat color.
- Apply coatings in a uniform thickness without skips or holidays. Hand or pressure rollers, depending on the job size, are best for this application. Neoprene coatings do not spray easily. However, other coatings may be sprayed. Allow each coat to dry until tack free and dry enough for foot traffic without damage before applying additional coatings. Several hours to overnight will be required, the time depending on drying conditions.
- Extend each coat over cants and up vertical surfaces of pads, curbs, walls and parapets. The top of curbs and equipment pads shall be similarly coated. In the case of walls and parapets, extend coating to the point where counter-flashing enters the masonry. Where no counter-flashing is specified, hold the base coats just short of the termination line at edge of deck to avoid seeping under masking tape or spilling on adjacent unprotected surfaces.
- If the entire job cannot be carried through to completion without interruption, the interruption should occur after the first base coat. This will provide protection for the tape system and general area.
Before resuming work, the surface must be well cleaned by washing with solvent-alkaline cleaner or liquid detergent. This cleaning is necessary to remove dirt accumulation and the surface film that forms on exposed neoprene or polyolefin. Failure to remove either can result in poor adhesion. In hot, sunny conditions, surface films can form on neoprene in as little as two days. Under such conditions it is best to schedule application to avoid interruptions. If they must occur, cleaning is essential to assure adhesion. GacoFlex U-68 Ure-Cap and U-6006 Ure-Shield must be primed with U-5677 or E-5511 if more than 72 hours have elapsed between coats. Remove oil or grease by solvent wiping. Solvent wiping must be done lightly and with extreme care to avoid lifting or wrinkling.
- Top coats should be applied the next day, if possible, after the final base coat. This will enhance adhesion. Note that the preferred time to interrupt a job, if necessary, is after the first base coat (See section 1E), not between the base coat and the topcoat.
- Inspect the roof for damage prior to the application of the topcoat. Any damage must be repaired by re-flashing, re-taping and replacing of base coat so that a continuous membrane in a substantially uniform thickness covers the entire surface prior to the application of the topcoat.
- Important: Stir all pigmented materials thoroughly before use.
- Apply topcoat over base coat in the specified coverage. Specified quantities are minimum and on an undiluted basis. The normal rate of application per coat is 3/4 to 1 gallon per 100 square feet (2.84 L to 3.78 L / 9.3 m²) (12 to 16 mils (.3 mm to .41 mm) wet) for Hypalon or polyolefin that may be applied by roller, brush or spray. Roller application is recommended where possible over neoprene base coats - especially where there may be wind. Use new rollers or roller previously used only in the same coating and cleaned in fresh solvent. The normal rate of application per coat of Ure-Cap and Ure-Shield is 3/4 to 1-1/2 gallon per 100 square feet (2.8 L to 5.68 L / 9.3 m²) (12 to 24 mils (.3 mm to .61 mm) wet). They may be applied with brush, roller or spray. New rollers should be used since it is not economically practical to clean them and the old ones will cure and become unusable.
- While careful color matching procedures are used in the Gaco Western plant, different batch coatings may vary slightly in hue. This variation will be too slight to be perceptible if changes are made at natural breaks in the surface. Some intermixing of batches may be necessary if changes cannot be made at natural breaks.
- Since the solvents used in topcoat material coatings are similar to those used in neoprene base coatings, the first topcoat may pick up some of the color from the base coating (this generally does not occur with U-68 Ure-Cap and U-6006 Ure-Shield). This is not objectionable, indicating a good bond of the two materials. The final topcoat covers the discolored first coat completely. In good drying weather, no more than 24 hours should elapse between coats.
- Remove masking tape at edges of coating area as soon as the final coat is applied. By removing the tape while the coating is wet, it will not be necessary to cut if off to avoid damaging the edge of the coating. Any seepage under the tape on rough surfaces can be wiped off with thinner while wet.
TOP COATS OVER TEXTURE
When applying topcoats over a texture, be sure texture is uniform and acceptable prior to applying the topcoat. Apply the topcoats at the specified rate in multi-directional passes. This insures a complete encapsulation of the texture. Brush, roller or spray may apply topcoats.