Gaco Western Elastomer Coatings Over Pre-Existing Single-Ply Hypalon® Roofing

PART 1 - GENERAL

1.1 SUMMARY

1. This specification provides a remedial coating system for application over a pre-existing single-ply Hypalon roof.
2. This specification assumes that the pre-existing roofing system is intact with no material or structural defects. Conditions to check and corrections to consider are as follows:
   1. The existing type of single ply roofing material must be identified as Hypalon.
   2. The existing Hypalon single ply roofing must be adequately bonded to the substrate and the insulation must be free from moisture. If moisture is suspected, obtain a moisture content survey. Remove and replace moist and inadequately bonded insulation. All pre-existing roofing must be well bonded and intact with sufficient slope (at least ¼" to the foot slope, (.64 cm to the .30 m)) to eliminate ponding water. Ponding water is defined as an area of 100 sq. ft. (9.3 m²) or ½" (1.27 cm) in depth within 48 hours after a rainfall.

NOTE: Slight scrim exposure is acceptable. Seams must be well adhered and or re-seamed. Recoating a single ply roof with faulty seams will not stop leaks. Consult Gaco Western’s Detail GW-5-D2 Crack and Joint Sealing for specific recommendations.

Single Component Hypalon: GacoFlex H-25 Series is economical, yet has higher physical properties. It offers good weather stability and excellent impact and abrasion resistance.

1.2 RELATED SECTIONS

1. Flashing and Sheet Metal: Section 07600
2. Drains, Vents, and Penetrations: Section 07700

1.3 SUBMITTALS

1. Product Data: Submit manufacturer’s standard submittal package including specification, installation instructions, and general information for each waterproofing material.
2. Applicator Qualifications: Submit current “Qualified Applicator” certificate from the specified waterproofing manufacturer.

1.4 QUALIFICATIONS

1. Primary waterproofing materials shall be products of a single manufacturer. Secondary materials shall be recommended by the primary manufacturer. Manufacturer shall have a minimum of 10 years experience in the manufacture of materials of this type.
2. Applicators shall have a minimum of 5 years experience in the application of waterproofing materials of the type specified. Applicator shall posses a current “Qualified Applicator” certificate from the specified waterproofing manufacturer.
3. Pre-Bid Conference: 10 working days prior to bid opening there is to be a mandatory Pre-Bid Conference. Anyone not attending the Pre-Bid Conference will not be allowed to bid the project. All products considered an equal to the specified product or any changes in the scope of work installation or specifications must be presented at the Pre-Bid Conference. If a change in the specifications is accepted, it will be considered as an alternate and will be presented as a bid amendment issued 5 working days prior to the bid opening. No other changes to specification or bid documents will be accepted.
4. Materials other than specified shall be submitted to the architect/owner for approval no later than ten days prior to bid date. In requesting prior approval, it shall be necessary to submit:
   1. A letter of certification, signed by an officer of the manufacturer, stating that the alternative material is equal to or better than the specified product.
   2. Independent laboratory test data giving physical property values in comparison to the specified material.
5. Pre-Installation Conference: Just prior to commencement of the fluid application waterproofing system, meet at the site with a representative of the coating manufacturer, the waterproofing contractor, the general contractor, the architect and other parties affected by this section. Review methods and procedures, substrate conditions, scheduling and safety.

1.5 DELIVERY, STORAGE AND HANDLING

1. Store all coating materials in the original unopened containers at 50° - 80°F (10° - 27°C) until ready for use.
2. Follow the special handling or storage requirements of the manufacturer for cold weather, hot weather, etc.
3. Safety: Refer to all applicable data, including, but not limited to MSDS sheets, PDS sheets, Product labels, specific instructions for specific personal protection requirements.
4. Ventilation: Provide adequate ventilation to prevent the accumulation of hazardous fumes during application.
5. Environmental requirements: Proceed with work of this section only when existing and forecasted weather conditions will permit the application to be performed in accordance with the manufacturer’s recommendations.

1.6 WARRANTY

A warranty is available for commercial projects only. Contractor must be eligible for, and make application to, Gaco Western, prior to the start of work under this section.

PART 2 - PRODUCTS

2.1 MANUFACTURERS

Acceptable Manufacturers:
Gaco Western

2.2 MATERIALS

1. Elastomeric Coating: Coating shall be GacoFlex H-25.
2. Misc. Accessories: All items incorporated into this system shall be compatible with and approved by the coating manufacturer.

Note: Allow additional material for rough or irregular surfaces add 2% - 3% for material loss during application.

PART 3 - EXECUTION

3.1 EXAMINATION

1. Verify that substrate is ready to receive work; surface is clean, dry and free of substances that could affect bond.
2. Verify that all other work involved with this area, done under other sections, has been completed and accepted by the architect and general contractor prior to starting the waterproofing application.

3.2 PREPARATION

1. Clean substrate using Gaco Western’s D-09 at a rate of one gallon per 300 sq. ft (3.78 L / 27.9 m²) to remove any and all surface contaminants. Apply D-09 with sprayer of choice, Hudson type agricultural sprayer, conventional pressure sprayer or airless sprayer. Use 3 to 4 foot arc pattern. Allow D-09 to stand for 5 minutes. Clean with commercial powerwasher, >2000 psi. Refer to Gaco Western’s General Instructions GW-1-1, Surface Preparation.
2. Mask off all adjoining areas that are not to receive the fluid applied waterproofing.
3. Blowers, air conditioning units and evaporative coolers shall be disconnected or otherwise modified to prevent contaminating the roof surfaces with condensate water, and to prevent solvent fumes from penetrating into the building.
4. Provide a suitable workstation to mix the coating materials.

3.3 INSTALLATION

1. Technical Advice: The installation of this waterproofing membrane shall be accomplished in the presence of, or with the advice of the manufacturer’s technical representative. Contact the nearest regional office for assistance.
2. Hypalon: Apply two coats of GacoFlex H- 25 Series. The coverage rate shall be no less than 1 gallon per 100 square feet (3.78 L / 9.3 m²) per coat. The color shall be white. Coat all surfaces including expansion joint covers and flashing.

   The H-25 Hypalon coating may be applied by roller or spray. Spray application is preferred for coating uniformity. Gaco Western's General Instruction Spray Guide SG-Hypalon should be consulted for equipment requirements.

   No traffic shall be permitted on the coated surface for a minimum of three days. Damage to the surface by other trades shall not be the responsibility of the coating contractor.

3.5 FIELD QUALITY CONTROL

1. The contractor for work under this section shall maintain a quality control program specifically to verify compliance with this specification. A daily log shall be kept to record actions in the field.
2. Inspections: A minimum of three (Substrate, Application and Final) inspections, by an approved manufacturer’s representative, will be required on all projects requiring a warranty.
3. Thickness: The dry film thickness of the GacoFlex H-25 Hypalon coating shall have an average of 8 dry mils (.20 mm). Exposed reinforcing scrim that increases surface area will require proportionate increases in coating to obtain the dry film thickness.