1. The owner/installer must prepare the substrate for the roof by addressing all of the conditions outlined here. Examine substrates to receive new roofing. Please do not proceed with the FlexRock Coating installation until unsatisfactory conditions have been corrected appropriately.

2. Make sure the TPO/PVC/EPDM/SPF substrate is free of delamination and defects (holes & other openings, tears, cuts, and open or partially opened seams).

If the defects are larger than 1/8”, repair before coating application.

3. Before applying FlexRock Coatings to the full roof surface, apply a 12″ x 12″ test patch to ensure adequate adhesion. Please refer to test patch application instructions.

4. Clean, dry and clear surfaces must be used to apply coatings or repair, free from dust, grease, wax, or other incompatible substances to facilitate appropriate adhesion. If grease, oils or heavy contaminants are present on the roof surface, remove them with a mild detergent prior to final cleaning. The use of bleach mixed with water can be used to remove algae, fungi, or vegetation. Thoroughly rinse surface and allow to dry prior to coating.

5. Roof decks that are deteriorated or structurally unsound should be replaced.


1. Blisters/Splits: To repair large splits/blisters, use polyester Reinforcing fabric 1/16″ thick in three layers and spread 2″ to 4″ beyond the split/blister area.

2. Flashing details, penetrations, and curbs, FlexRock Coatings 1/8″ thick shall be applied over the substrate. The edges of the coatings shall be feathered for the water to flow over the flashing details.

3.Roof Drains: Clear all existing build-up from around drains and sumps after removing the clamping ring. FlexRock Coatings across the entire drain/sump area.

4. Membrane Repair: Check the roof substrates carefully for defects (holes, openings). When repairing defects over 1/8″ wide, use polyester reinforcing fabric. Add a thick coating in a three-course fashion and spread to 2” to 4” beyond the repaired areas.

5. Fasteners: Cover all fasteners with FlexRock Coatings to ensure a watertight seal.

6. Curb Flashings: All curb flashings shall be dressed in at least a 2” wide x 1/8” thick of FlexRock Coatings

7 .Curbed AC Units: All curb flashings shall be covered with at least a 2” wide x 1/8” The perimeter shall be FlexRock Coatings FX-100

8 .Penetrations: FlexRock Coatings shall be applied around the base of the penetration, extending at least 4” onto the vertical and 4” onto the base. Use additional material if needed

9 .Seams: All seams and areas around roof protrusions (vents, scuttle hatches, pitch pans, etc.) are to be treated with FlexRock Coatings FX-100 at 1/8” thickening agent such as crushed walnut shells may be used if needed to achieve a watertight reinforced seal.

10. Skylights All exposed skylight fasteners shall be covered with FlexRock Coatings FX-100 All curbed corners joints shall be covered FlexRock Coatings at least 2” wide x 1/8” thick.

11. Prior to applying FlexRock Coatings, inspect the preliminary work / flashing details for problem areas (e.g., gaps, cracks, fish mouths, air pockets, etc.).

Metal Roofs

The FlexRock Coating system can be used on metal roofs that are at least 24 gauge or heavier.

Remove loose coatings, paint, rust, and scale using a wire brush and scraper, or by water blasting. Using a minimum 2,400 psi blasting setting, wire brushing, and power or hand sanding will help you remove loose rust.

Encapsulate all fasteners using FlexRock Coatings.

A visual inspection of the entire base coat should be performed after the application is complete. After curing, inspect for defects and repair as necessary.

Note: Total minimum coating System Dry Film Thickness(DFT) for the entire coating system shall be a minimum of 32 mils nominally.

A FlexRock Coating should not be considered for:

1. Surfaces prone to pedestrian traffic, decks, and frequent traffic bearing.

2. Surfaces that are not prepared, including but not limited to wet, dusty, oily, mildewed, heavily chalked, blistered, or otherwise structurally unsound surfaces.

3. Oil-bleeding and solvent-bleeding materials. The list includes, but is not limited to, some vulcanized rubber products, tapes, failed sealants, some caulking compounds and asphaltic/mastic materials without appropriate preparation.

4. Surfaces where adhesion has not been verified by testing.

IMPORTANT: FlexRock Coatings can only ensure product performance if the applicators strictly adhere to this specification.

FlexRock Coatings Management must approve any changes to specifications in writing.


6. Keep away from food. If rain is expected within an hour of applying the product at temperatures below 35°F (2°C), don’t apply it. Be sure to secure the pail and tighten the lid when transporting. Store in a cool, dry, shaded location. Ensure lid is completely sealed.


PULL-TESTING (BEFORE APPLICATION): For best results, conduct a pull test polyester high-performance reinforcement fabric to test the surface and to ensure no contaminants are present before application.

STANDARD APPLICATION: For 5 minutes, mechanically mix all of part A, making sure to scrape the sides and bottom. The product contains minerals that settle during storage, making cordless drill mixers unsuitable. Double auger mixers or other powered concrete mixing drill is recommended. After pre-mixing part A, add full part B while mixing. Continue mixing until fully combined, 2-3 minutes. Set up your work area and ensure that you can use all of the mixed products within 30-40 minutes.

Poured-In -Place into work area and spread with notched squeegee, backroll immediately.

  • Use 3/8” to 1” nap rollers.

  • Use smooth or notched squeegee3

  • Use short bristle brush/roller on smooth substrates.

  • Use longer bristle brush/roller on rough substrates.

(Care should be taken to back-roll immediately before coating begins to setup) Because the product constantly bonds to itself, a wet edge is not required.

THICKENING: When a thicker product is needed to fill cracks or build up, follow small batch instructions and use any of the pre-approved thick-eners to achieve the thickness desired. Thickeners include: hemp hurd, crushed walnut shells, fumed silica, crushed polyethylene, and powdered polystyrene.

STORAGE: Ensure that stored products do not freeze. Store in a cool, dry place. Part B must be kept free of moisture. Keep the container closed. Leave Part B open and it will absorb moisture and create CO2 gas, which leads to pressure buildup. If possible, store part A pails upside down.

SHELF LIFE: is recommended that you use all product within 1 year. If product has been stored longer than 6 months, shaking can aid in freeing settled minerals.


Flexible Rock Coating is super versatile it can be applied extra thick for added protection. Since there is no maximum mil thickness the user is not limited to a coverage rate. The amount applied beyond the recommended minimum coverage of 32 mil applied is completely up to the user.

Coverage rates can vary depending on the type of surface, surface condition and application technique.

Typical coverage Rate on a flat smooth surface. One FlexRock Base 5-Gal Kit Covers 200-250 Sq ft of flat smooth surfaces. Sq. Ft/Kit 32 ml @ 250 Sq. *Depending on technique & surface condition.