Don't reroof. Restore.
The cost-effective, long-term solution for restoration of structurally sound metal roofs
The HydroStop® System
A liquid-applied acrylic elastomeric system for recover and reroof applications.
Step 1: Prep the roof | GAF HydroStop Metal Roof Restoration
Step 2: Prime rust areas | GAF HydroStop Metal Roof Restoration
Step 3: Seal seams | GAF HydroStop Metal Roof Restoration
Step 4: Detail penetrations | GAF HydroStop Metal Roof Restoration
Step 5: Coat the roof | GAF Hydrostop Metal Roof Restoration
The HydroStop System Project Profile | GAF Roofing
1. Prep the roof
- Ensure the roof is clean, dry, and tight.
- Make any necessary repairs to the sheet metal. All loose or missing fasteners must be secured or replaced.
- Power wash the roof using GAF United Cleaning Concentrate (UCC).
- To divert water away from areas of the roof susceptible to leaks, install sheet metal crickets as needed.
Application rates:
Dilute with water at a 1:10 ratio. Apply the diluted cleaning solution to the substrate at the rate of 1.5 Gal/Sq.
2. Prime rust areas
- For light rust use GAF Acrylex 400 primer. For heavier rust that is showing signs of spreading, use our one-part urethane based Lockdown Primer.
Application rates:
Acrylex 400 Primer Application rate: 0.33 - 0.67 gal per 100 square ft.
LockDown Primer Application rate: 0.25 gal per square ft.
3. Seal seams
- Seal ridges and rake edges using a roof brush with 12" HydroStop® Fabric and HydroStop® Foundation Coat (three-coursed).
- Vertical seams: Seal with HydroStop® Butter Grade Flashing.2
- Fasteners: Encapsulate all fasteners using HydroStop® Butter Grade Flashing.
- For an alternate flashing option, FlexSeal Caulk Grade can also be used.
Application rate:
HydroStop® Butter Grade at a rate of 2.0 Gal/Sq.
4. Detail penetrations
- All details including curbs, ridges, and pipe penetrations must be sealed using a roof brush with 12" HydroStop® Fabric and HydroStop® Foundation Coat (three coursed).
Application rate:
HydroStop® Foundation Coat at a rate of 1.00-1.50 Gal/Sq
5. Coat the roof
- Apply HydroStop® Finish Coat per the warranty length. HydroStop offers warranty options of 10, 15, and 20 years. HydroStop FinishCoat can be applied using a brush, roller, or sprayer.
- A minimum of two coats is required. The second coat should not be applied until the first coat has dried (which can take up to 24 hours).
Application rates:
10 year Warranty: 1.50 Gal/Sq (two coats of .75 Gal/Sq. each coat)
15 year Warranty: 2 Gal/Sq (two coats of 1 Gal/Sq. each coat)
20 year Warranty: 3 Gal/Sq (three coats of 1 Gal/Sq. each coat)
5 Products in the HydroStop System
GAF United Cleaning Concentrate (UCC)
For the proper cleaning of existing elastomeric coatings on roofs, metal surfaces, concrete, and masonry substrates as well as uncoated roof, deck, and wall surfaces. UCC Cleaner will help to remove debris from the roof improving adhesion during the application process.
GAF Acrylex 400 Primer or LockDown Primer
Acrylex 400 Primer is a water based primer formulated to protect areas of the roof with light rust. LockDown Primer is a Urethane based Primer used to treat more severe rust that is spreading. LockDown Primer protects severely rusted areas and stop them from continuing to rust
Enhanced warranty coverage available
Certain projects installed by GAF Master, Master Select™, or Premium Coating Systems contractors may be eligible for enhanced warranty coverage.*
*See HydroStop® PremiumCoat® Liquid-Applied Roofing Manual for specific requirements and restrictions.
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