Installation Guide Specification

Preserving BUR & Mod Bit Roofs

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I.   General

1.01    SUMMARY

  • Provide labor, materials, equipment and supervision necessary to install spray applied elastomeric acrylic coating system as outlined in this specification to preserve and extend the service life of built-up and modified bitumen roofing.
  • The manufacturer's application instructions for each product used are 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 preserving built-up and modified bitumen 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 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 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, sheet metal work, etc. This work should be outlined by the contractor before work commences, and shall be performed observing good trade practices.



  • 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 15

Volume Solids %
Weight Solids %


> 50
> 65

  • The reinforcing fabric shall be Tietex T272 or an equivalent that meets the following physical property requirements:


Test Method

Average Value




Weight (per sq. yard)

Calculated by formula

3 ounces

Bursting Strength (lbs)

ASTM D3786


Tensile Strength (psi)

ASTM D1682


Tear Strength (lbs)

ASTM D1117


Elongation (%)

ASTM D1682





Ease of Saturation




  • 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.


  • The surface must be clean, sound, dry and free of any materials that would inhibit proper adhesion of the coating or sealant. Achievement of this condition may require the use of INDUSTRIAL CLEANER, scraping, power brooming, vacuuming or other means, and shall always be performed observing responsible trade practices.
  • On built-up roofs with mineral cap sheet with moderate granule sluff, apply CLEARSEAL A101 surface sealer to the entire roof surface at the rate of at least ½ gallon per 100 square feet.
  • On built-up roofs with gravel, the entire roof shall be spudded to as smooth a surface as possible. After spudding, cleaning and preparing as specified herein, apply as much LIQUISEAL asphalt emulsion as necessary for leveling off the entire surface.
  • Repair all cracks, voids, holes or other surface imperfections in the roof field or flashing areas with ACRYFLEX® or ACRYSHIELD A503 as appropriate. After allowing the sealant or coating to dry (normally at least 24 hours), these areas shall be coated with ACRYSHIELD A503, applied at the rate of at least 2 gallons per 100 square feet. T272 polyester reinforcing fabric shall then be embedded in the wet coat of ACRYSHIELD A503, with a second coat of ACRYSHIELD A503 being immediately applied on top of the fabric, at the rate of at least 1 gallon per 100 square feet. The polyester fabric shall extend 4-6 inches beyond the area in need of repair. Both the first and second coats of ACRYSHIELD A503 shall extend 2 inches beyond the edges of the polyester reinforcing fabric.
  • All blisters shall be cut, dried out, re-adhered and sealed with appropriate roof mastic. After allowing sealant to dry, apply the ACRYSHIELD A503 and polyester reinforcing fabric as described in Section 3.03, Paragraph C of this guide specification.
  • Seal all HVAC ductwork joints as needed with ACRYFLEX and reinforcing polyester fabric or BUTYL SEAM TAPE. Coat entire duct assembly with two 1½-gallon coats of ACRYSHIELD A400.
  • Reseal around all mechanical equipment and roof penetrations with ACRYFLEX.
  • All loose seams, ridges and other membrane deficiencies of existing roof system shall be fastened down and sealed with ACRYFLEX. Sealant must seal fasteners as well. After allowing sealant to dry (normally at least 24 hours), apply ACRYSHIELD A503 and polyester reinforcing fabric as described in Section 3.03, Paragraph C of this guide specification.
  • All valley areas, waterways, drain areas, penetrations or other area where potential water accumulation is a concern, apply ACRYSHIELD A503 at the rate of 2 gallons per 100 square feet, approximately 46 inches wide. Immediately embed 40 inch wide T272 polyester reinforcing fabric into the wet coating, with a second coat of ACRYSHIELD A503 being immediately applied on top of the fabric at the rate of 1 gallon per 100 square feet. Both the first and second coats shall extend a minimum of 2 inches beyond the edges of the polyester reinforcing fabric. In any large valley area, multiple widths of fabric should be used, overlapping them a minimum of 3 inches so that the coating and fabric extend at least six inches up above the potential waterline.
  • Allow coating to dry thoroughly (normally 8 to 24 hours depending on weather conditions), before proceeding to application of the remainder of the roofing system as described in section 3.04 of this guide specification.


  • After thorough preparation as necessary, the entire roof shall receive the ACRYSHIELD Roof Management System consisting of 3 gallons per 100 square feet of ACRYSHIELD, applied evenly in two separate coats.
  • Apply a base coat of ACRYSHIELD A503 coating by spray or roller at a rate of 1.5 gallon per 100 square feet. Allow to thoroughly dry for normally 8 to 24 hours depending on weather conditions.
  • Apply a top coat of ACRYSHIELD A400 coating in a crosshatch technique at a rate of 1.5 gallon per 100 square feet. Allow to thoroughly dry before exposing to foot traffic.
  • All coating edges shall be cut evenly in a uniform manner so as to provide an aesthetically pleasing appearance.


  • In case of manufacturer’s labor and material warranty - Manufacturer’s Field Services: Inspection by the coating manufacturer'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 the ACRYSHIELD Roof Management System 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:

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