National Coatings Blog

Metal Roof Coating Systems Permit Restoration of Degraded Metal Roofs

Posted by Nicole Gale on Thu, Apr 09, 2015 @ 08:30 AM

028Metal roofing has a reputation of being an extremely durable roofing substrate that has been successfully used on buildings for over 70 years.  Many warehouses, agricultural facilities, food processing, heavy equipment manufacturing, schools and now churches use metal roofing as they provide excellent strength with heavier gauge steel, speedy installation and lower upfront costs over traditional roofing systems. Extending the life of an aged metal roof by using a metal roof coating system is a viable and excellent option as opposed to the other available options of single ply membrane retrofits, roof hugger systems (additional metal layover of the existing metal panel) or the most expensive and disruptive complete removal and re-skin option with all new metal.  Recoating metal roofs can lower roof maintenance and prolong the lifespan of the roof indefinitely, when maintained properly.

As a metal roof ages, the factory applied coating be it galvanized, baked on paint, Kynar or even Anodized protection of the metal panels deteriorate, fasteners break, seams fail, and rust occurs. When the protective coatings that are baked onto the metal panels during manufacturing have worn off, the panels are exposed to environmental elements making them vulnerable to roof failures. The fasteners, which hold the panels together, deteriorate over time and begin failing due to the roof constantly expanding and contracting. This occurs due to normal every day temperature fluctuations and are increased drastically when there are sudden swings in temperature such as a cold fronts, hail impact and rain cooling off of a heated surface in the summer when temperatures of the panel can be in excess of 150+ degrees. These broken fasteners and open seams occur due to stress related exposure and become avenues for water that will surely penetrate the system and enter the building’s interior. Sealants, tapes and caulks that have no UV protection commonly used to waterproof joints and areas between the panels, lose their elongation and recovery abilities, making it difficult to keep up with the buildings‘ constant movement without weakening. Screws and washers become loose and fall off, needing inspection, tightening and replacement. Metal panels can develop rust, needing either full replacement of the panel or the use of a special rust inhibitive primer to restore the panels. The application of rust inhibiting primers are commonly left unprotected and eventually fail. The most common repair material used is asphaltic mastics and should never be used as it is not even meant to be applied directly to a metal panel and must be removed prior to any application of an approved coating for these metal structures.

Recoating a deteriorating metal roof using one of our AcryShield Metal Roof Coating Systems will allow you to solve all the issues mentioned above and leave you with a fully restored, watertight, maintainable and sustainable roofing assembly.

Restoring the roof involves the removal of rusted panels by cutting out the areas that have fully rusted through the panels and replaced with new and like profile to the original so as to promote a solid and continuous seal to the original panel(s). Our low VOC primer, RustShield is then applied to fully combat future rusting of the panels. The AcryShield System offers a choice depending on the severity of degradation to the existing metal. A butyl tape with cloth backing can be applied over all seams and around the base of penetrations, curbs and flashings for a fully sealed and watertight substrate. Screw heads can be encapsulated with either a trowel grade or brush grade AcryFlex mastic and if warranted due to extreme movement/failure a 3-course application of mastic and membrane can also be used to negate future expansion and contraction issues in lieu of the butyl tapes. Next, a base coat with excellent adhesion to metal is installed for exceptional waterproofing. Finally a finish coat containing an industry leading UV protection package is applied. The end result is an easily maintainable and renewable solution that provides long-term performance and low life-cycle cost, along with the added bonus of increased energy efficiency. 

Download our FREE Metal Roof Coating Systems Brochure for additional information or call us at 800-423-9557.

FREE GUIDE: Metal Roof Coating Systems

Tags: Metal Roofing Systems, Metal Roof, Metal Roof Paint, Restore Metal Roof

Metal Roof Coating Systems Restore Roof Corrosion on Metal Roofs

Posted by Nicole Gale on Thu, Jan 22, 2015 @ 08:30 AM

036Metal roofing is a popular roofing option for commercial buildings as they offer excellent strength and ease of application. When these roofs begin to fail, they often fail around grommets and sealants that fasten the metal panels together. This is where water penetration occurs and rust develops. Over time, the rust eats at the metal panels, weakening their strength and causing overall concerns to the performance of the metal roof. This needs to be addressed and eliminated before too much structural damage occurs.

Combating Rust

Since rust is one of the most destructive elements a metal roof can experience, we must remove and stop all rust from occurring and spreading. Metal roof coating systems are able to restore roof corrosion with the use of RustShield – a rust-inhibiting primer. When restoring metal roofing, rust is eliminated by cutting out and removing the panels that have fully rusted through the metal, as they cannot be restored, and by the use of RustShield. The RustShield primer completely combats any current flash rusting while providing outstanding corrosion protection against any future rust from occurring. This allows a roof coating system to be installed over the metal roof, restoring the roof without the need to do a cost roof replacement.

FREE GUIDE: Metal Roof Coating Systems

Restore Roof Corrosion

Once all the rust has been removed and combated, butyl tape is installed over seams and screw penetrations for a fully sealed substrate. Then the metal roof coating system is installation begins. A base coat is installed to provide excellent waterproofing, superior adhesion, and resistance to ponded water. Custom, localized polyester reinforcing fabric may be embedded into the base coat at necessary areas to ensure durable strength to the roof membrane. Finally, a topcoat is spray applied across the roof top, providing excellent UV protection, longevity and brightness for reduced roof maintenance and energy efficiency and cost savings.

For additional information on metal roofing, download our FREE Metal Roofing Brochure and check out some of our Metal Roof Case Histories – U.S. Coast Guard Hangar at LAX, Hundley Hardware Co., GateGourmet, and Sears Warehouse

Commercial Roofing Contractors

Tags: Metal Roof, Restore Metal Roof

RustShield Provides Superior Resistance to Corrosion on Metal Roofing

Posted by Nicole Gale on Tue, Nov 04, 2014 @ 09:30 AM
Metal roof substrates are very popular for commercial roofing because of their strength and ease of application. After some time, these roofs need to be maintained because the grommets and sealants begin to weather, causing rust to develop. Over time, the rust will weaken the long term performance of the roof, causing leaks and other damage to the substrate.

National Coatings has a lasting and durable solution to solving rust issues - RustShield A120, a high performance rust primer that inhibits the future growth of rust after it has been removed in the preparation phase of application. 
RustShield A120 is a single component, low VOC, water based rust-inhibitive primer. It is used over ferrous and non-ferrous metal surfaces to provide excellent resistance to flash rusting and outstanding corrosion protection.

This primer is ideal over:
  • Metal Roof Decksnasa-1
  • Metal Side Walls
  • Rail Cars
  • Pipes and Other Metal Equipment
  • Tank Exteriors
  • Structural steel
NASA chose National Coatings' RustShield A120 product to be used on their Ares I-X rocket due to its superior strength and ability to shield against rust. RustShield allowed NASA to maintain the rocket's exterior integrity while it passed through the salty air above the ocean before entering into Space.
FREE GUIDE: Metal Roof Coating Systems

Tags: Coating Metal Roofs, Metal Roof Coating, Metal Roof, Restore Metal Roof, rusting roof, rust on roof