Installation Guide Specification for Recoating SPF Roofs

Recoating SPF Roofs

PDF Logo Download PDF Version


1.01    SUMMARYProvide labor, materials, equipment and supervision necessary to install spray applied elastomeric acrylic coating system as outlined in this specification to create seamless weatherproofing over existing sprayed polyurethane foam (SPF) and coating roofing.

  • The manufacturer's application instructions for each product used are to be considered part of these specifications and should be followed at all times.


  • Submit product data sheets and literature verifying fire ratings and physical properties of materials.
  • Submit material safety data sheets.


  • Supplier Qualifications: The ACRYSHIELD®  Roof Management System for recoating SPF roofs, as supplied by National Coatings Corporation, is approved for use on the project.
  • Applicator Qualifications: The applicator shall be approved by National Coatings Corporation to apply the system. Manufacturer's written verification of applicator approval is required.


  • Containers and Packaging: Deliver materials in original sealed containers, clearly marked with: manufacturer’s logo; full product name; and lot number(s).
  • Storage: Store materials between 40ºF and 100ºF with careful handling to prevent damage to products. If conditions exceed these ranges, special consideration in storage must be taken. Do not store at high temperatures in direct sunlight.
  • Protection: Protect all materials from freezing and other damage during transit, handling, storage, and installation.


  • These recommendations are for maintenance of an existing coating system and not intended for correction of badly deteriorated roofing systems that may need replacement.
  • These recommendations assume that the foam system is sound, well adhered and is not saturated or leaking in any areas.
  • These minimum recommendations for material usage are for ideal conditions. The number of gallons per 100 square feet may need to increase due to uneven application, rough surface texture, wind conditions while spraying and/or other variables.
  • Wet insulation must be thoroughly evaluated and then addressed with removal or other measures. Consult a National Coatings Technical Consultant regarding the need for moisture surveys and other assessments.
  • Structural cracks should be referred to the appropriate National Coatings Technical Consultant.
  • This installation guide specification assumes that the deck, if plywood, has no dry rot, and is in sound condition, or has been repaired.
  • Do not apply materials unless surface to receive acrylic roofing system is clean, dry and prepared as specified.
  • Install all material in strict accordance with all published safety, weather, or applicable regulations of the manufacturer and/or local, state, and/or federal agencies which have jurisdiction.
  • The entire system shall be fully adhered to the surface on which it is applied. Voids left under the system by creating bridges are not acceptable.
  • Do not proceed with application of coating or sealing materials when temperature is less than 50ºF. No coating system shall be applied if weather will not permit it to dry prior to exposure to precipitation or freezing.
  • Heavy puddles of coating on the roof are not acceptable.
  • Instructions for use of all roofing materials and application equipment should be read and followed at all times. 
  • As a general principle, to prevent the ponding of water, install additional drains as necessary or install drainage systems with sprayed polyurethane foam (SPF).


  • This specification does not extensively outline procedures for preparation and finishing of drains, vents, ducts, flashings, parapet walls, etc. This work should be outlined by the contractor before work commences, and shall be performed observing normal trade practices. In most cases the self-flashing attributes of the foam will be utilized without the need for additional flashing materials. In any case, the foam should never be applied in a manner that traps moisture or forces moisture to migrate underneath the system.



  • The roofing system is an acrylic, elastomeric, spray-applied ACRYSHIELD Roof Management System manufactured by National Coatings Corporation.
  • Physical Properties of Cured Roofing System: The testing of the coating shall be done under ASTM-D6083, “Standard Specification for Liquid Applied Acrylic Coating Used in Roofing”, unless otherwise specified.
    • The roofing system shall have good resistance to ponding water.
    • The roofing system shall contain no plasticizers.
    • The roofing system shall contain no migrating fire retardants.
    • The roofing system shall have a Class A fire rating on a noncombustible deck when tested according to the procedures outlined in ASTM E-108.
    • The top coat shall also meet the following physical property requirements:


ASTM Method


Tensile Strength, psi (Max @ 73ºF)


Minimum 250

% Elongation @ Break (73ºF)


Minimum 250

Permeance, perms


Maximum 20

Volume Solids %
Weight Solids %


> 50
> 65


  • Flashing, adhesives, thinners, elastomeric caulking compounds, primers, and similar materials shall be approved by the manufacturer of the coatings. All materials used shall be applied in accordance with its manufacturer's recommendations.




  • Compliance: Comply with manufacturer’s product data, including product technical bulletins and product guide specification instructions.
  • Inspect surfaces which will receive the ACRYSHIELD Roof Management System to make sure they are clean, smooth, sound, properly prepared, and free of moisture, dirt, debris, or other contamination.
  • Verify that all roof penetrations, mechanical equipment, cants, edge metal, and other on-roof items are in place and secure.

  • Verify that all critical areas around the immediate vicinity of the spray area are suitably protected

  • Verify all roof drains are clean and in working order.

  • Verify that all air conditioning and air intake vents are suitably protected or closed.


  • All surfaces to be coated must be clean, sound, dry and free of any dirt, grease, oil, debris or other contaminants which would interfere with proper adhesion. Pay particular attention to the low areas on the roof, where more contaminants may have settled. Loose coating should be removed prior to application of coating. Any wet areas must be removed and/or dried out prior to application of coating.
  • Exposed SPF areas that are small must be brushed with a stiff bristle broom to remove the degraded SPF prior to caulking with ACRYFLEX®  and coating.

  • Caulk or fill all cracks, holes or other surface imperfections with a high quality elastomeric caulk or sealant designed for roofing applications, such as ACRYFLEX. All caulk or sealant must be thoroughly dry before application of coating. NOTE: Silicone sealants are not compatible with acrylic coatings.
  • Start repair of large damaged and deteriorated areas by removing existing coating and SPF down to dry, good quality SPF. This requires close observation to insure that the removal operation is extended both horizontally and vertically to the point where all wet, contaminated, and deteriorated SPF has been removed. The damaged SPF must be removed by mechanical scarifying equipment to a minim mum depth of ½ “or until good SPF is determined, whichever is greater. Removal of SPF by hand is not acceptable. These areas shall receive an extra two coats of ACRYSHIELD before coating the entire roof. Large or deep areas of foam removal may require the application of additional foam prior to coating. Apply a minimum of ½” new SPF. Do not remove an area larger than can be refoamed and base coated in the same day.


  • Any areas of bare foam should receive two coats of ACRYSHIELD prior to coating the entire roof.
  • After thorough preparation of the existing surface, the entire roof shall receive two separate coats of ACRYSHIELD.

  • The first coat of ACRYSHIELD A500/A510 should be evenly applied at the rate of 1½ gallons per 100 square feet by spray or roller. If spraying, backroll the first coat. Apply enough pressure on the roller to work the coating into all the rough areas of foam.

  • Allow the first coat to dry thoroughly, approximately 4 to 12 hours, prior to the application of the second coat.
  • The second coat of ACRYSHIELD A500/A510 should be evenly applied at the rate of 1½ gallons per 100 square feet by spray or roller.
  • Heavy puddles of coating should not be left on the roof. All coating should be distributed evenly at the specified rates of coverage.
  • The total AcryShield system should have a minimum dry film thickness at any location of 24 dry mils.
  • CLEAN-UP: ACRYSHIELD is water based for ease of application and clean-up. Cleaning of hands and tools should be done immediately following application, using warm or hot soapy water.


  • In case of manufacturer’s labor and material warranty - Manufacturer’s Field Services: Inspection by National Coatings Corporation’s representative shall be made to verify the proper installation of the system. Any areas that do not meet the minimum standards for application as specified herein shall be corrected at the contractor's expense. Manufacturer's inspection or verification shall not constitute acceptance of responsibility for any improper application of material.

3.06    CLEANING

  • Surfaces not intended to receive foam insulation and/or elastomeric coating materials shall be protected during the application of the system. Should this protection not be effective, or not be provided, the respective surfaces shall be restored to their proper conditions by cleaning, repairing or replacing. All debris from completion of work shall be completely removed from the project site.


The following materials listed in these recommendations are available from National Coatings Corporation:

  • ACRYSHIELD® A500/A510  acrylic, high-performance, elastomeric roof coating.
  • ACRYFLEX® acrylic architectural sealant; available as A150 trowelable grade.