National Coatings Blog

When applying a roof maintenance system over your existing roof, the preferred weather conditions are dry with low humidity. While these conditions are the ideal conditions, using an AcryShield Quickset product can allow for added application time during high humidity, light rain and heavy dew.

National Coatings recommends checking the projected weather forecast to insure no rain is predicted for the immediate future. It is important to allow for plenty of time to permit the coatings to set and cure guaranteeing a monolithic, leak-free surface. Roof maintenance systems should be applied in temperatures exceeding 50F to avoid curing issues and freezing. Wind should be minimal when spray applying as each square foot requires a certain amount of roof coating thickness to provide optimal protection and coverage to your building. Windscreens can be used to avoid over-spray to near-by buildings and parking lots.

While some coatings are not recommended in high humidity, light rain or heavy dew, National Coatings has a line of Quickset base coats and top coats that provide excellent resistance to early wash-off during these conditions. A surface tension is created, allowing for a greater window of opportunity to complete your roof maintenance job. For more information on these Quickset products, download our FREE Quickset Brochure and find out how you can benefit from one of these coatings that provide optimum adhesion to Asphalt, Single-Ply, Metal, SPF and Concrete roofing.

Introduction

One seldom mentioned benefit of the National Coatings AcryShield product line is that the coating can be easily recoated over itself.  Thus, after a decade or more of successful performance, when the coating becomes thin, additional coating millage can be applied without extensive preparation.
 
Recoating with AcryShield

Preparation
Before recoating, the coated roof surface must be clean, dry and free of materials that would compromise adhesion.  This includes dirt, chalked coating, and other airborne materials that may have accumulated, such as grease, and particulate material from nearby exhausts.  Typical cleaning techniques involve the use of pressure washer.  Be sure to keep the pressure to a minimum to avoid damaging the underlying roof membrane seams.  National Coatings Corporation Cleaner or common TSP may be required to thoroughly clean the originally coated roof.
 
After the roof is cleaned, there is a simple technique to insure the roof is sufficiently clean for recoating.  A piece of masking tape is pressed onto the roof and peeled off.  If the tape adheres well, and does not come off easily, the roof is sufficiently clean for recoating.  However, if the tape comes off easily, and carries with it chalked coating, dirt, mildew or other particulate, the roof is not clean and must be recleaned. 
 
Cracks and Punctures in the Coating and Underlying Membrane
During the service life of the roof, punctures, holes and cracks may have occurred in the coating.  These cracks may extend through the coating and well into the roofing membrane below.  The repair will be different depending on the type of roofing membrane. 
 
For asphalt, modified bitumen, and sprayed polyurethane foam (SPF), National Coatings Corporation AcryFlex trowelable sealant can be applied over the crack or hole with a spatula.  The sealant should be pressed into the membrane being sure there is no air trapped under the sealant.   Large cracks, greater than 1/8" wide should be reinforced with P272 polyester reinforcement scrim.  Large holes in SPF roofs may require a foam "plug" to be inserted into the hole.  The plug should be imbedded and sealed with AcryFlex sealant.
 
For thermoplastic and thermoset single plies, a piece of P272 polyester reinforcement 6" larger than the edge of the puncture and pressed into the AcryFlex trowelable sealant.  A second application of AcryFlex is applied.  After drying, AcryShield coating is applied.  
 
An alternative repair technique for EPDM is to first clean the coated roof, then apply a patch of a non-vulcanized peel-and-stick material.  The roof can be coated immediately after applying the patch.
 
Applying the Coating
The coating can then be applied to the cleaned roof surface.  The technique is analogous to applying the original coating.   For specifics, follow the Guide Specifications found on the National Coatings Corporation website.
 
Summary
The roof has now been restored to its original condition and original solar reflectance.  This process can be repeated many times over, saving the building owner countless thousands of dollars in reroofing expenses. Moreover, since this recoating does not qualify as a recover roof, it is not bound by the code requirements allowing only 2 roofs to be installed before both must be removed due to load constraints.  For the contractor there is an immediate economic benefit: it creates an easy opportunity for repeat business with an established client.