An Overview of Fluid Applied Roof Coatings .
….for application on low-slope roof systems
As an alternative to wholly new roof installations, applying fluid-based coatings and sealants can restore and prolong the life of existing low-slope or flat roofs. Fluid applied coatings, on flat roofs, provides a less involved and less costly alternative to full replacement. With continuing advances in coating technologies, roof recoating can be considered as a minimally disruptive option for extending roof life at lower expense.
It is important to determine if recoating is advisable for a given roof, and which coating suits it best. Some roofs are just too far gone and in such bad condition that they are not applicable options for roof coating applications. Clients can still choose a coating option, but there are levels of wear, deterioration, and damage that can NOT be repaired by coatings alone. A professional roofing contractor like us here at StructoFlex.com can help by explaining some of the technical characteristics of coatings and we can analyze the current condition at the exposed surfaces of your roof.
By thoroughly assessing the current roof assembly and thoughtfully selecting an optimal coating system, owners can make informed decisions on roof rehabilitation. This can allow for improving performance and prolonging service life in a cost-effective manner. Understanding the criteria helps in evaluating recoating feasibility and matching high-performing coatings to enhance roofing assets over the long term.
Existing roof systems nearing the end of their service life present prime opportunities for recoating, provided they have historically performed well and are sufficiently good condition to be sustainably coated as a stand-alone treatment. Facility managers should view roof coatings as a means to prolong the lifespan of current membranes, not as equivalent to new roof installations.
Before proceeding with recoating, a pro must inspect roof conditions and detailing. This confirms recoating suitability and identifies necessary repairs beforehand. Coatings cannot resolve existing deficiencies. Visual examinations and nondestructive testing like infrared scanning pinpoint leakage-prone areas needing attention at flashings, edges and penetrations. Addressing compromised insulation, membrane failures and watertightness issues lays the groundwork for recoating success.
Fluid-applied systems can be applied in methodologies similar to elastomeric acrylic materials, yet can offer protective waterproofing, weatherproofing, and reflectivity benefits when applied over modified bitumen, metal and BUR roof systems. The thick viscous liquids can fill cracks, seal seams, and provide a fully adhered protective layer both in wholesale and in patch locations. Acrylic coatings contain reflective pigments to reduce heat gain, these materials are less expensive and work as a protective cover over modified bitumen materials to extend the system longevity by protecting to a degree from exposure to ultraviolet rays. Silicone has extremely low vapor permeability. Unlike most water based acrylics, silicone materials remain somewhat flexible, for some time, to withstand expansion and contraction. Liquid application allows the fluid to fully saturate or cover roof substrates and detail areas, unlike sheet membranes. One of the differences is that fluid applied systems can infiltrate access detail areas that are particularly difficult to cover with sheet applied systems. Examples include scupper areas, complex planar joints, and areas with difficult accessibility or restricted spatial constraints. Proper surface preparation both through mechanical or chemical applications may be necessary to improve adhesion. Targeting leak-prone areas, edges, penetrations, and seams maximizes the lifecycle extension benefit. Certain systems require additional prep work at these critical non-field areas.
Aluminum paint coatings generally have moderate initial reflectivity, yet aluminum paint coatings lack the continuous film-forming capacity, weather resistance, and long-term durability of acrylic, silicone and epoxy fluid-applied roof systems. The inorganic pigmented coatings have significant limitations on roofing substrates.
Acrylic coatings contain acrylic polymers as the primary binder, plus pigments for color and reflectivity. Common polymers include polymethyl methacrylate (PMMA) or acrylic-styrene emulsions. Titanium dioxide or aluminum trihydrate are typical reflective pigments, but their efficacy is significantly limited as a protectant to UV for more than a handful of seasons of exposure, and they have near no waterproofing capabilities to roofs with significant wear. As well, one of the biggest limitations to acrylic roof coatings is that they cannot be applied in any areas of ponding and they do not actually seal or stop any type of existing leakage even if it is limited to general or overall surface deterioration.
Silicone coatings are generally comprised of silicone resins formed from siloxane polymers and reinforced with silica to enhance durability. These systems also often contain pigments, biocides, and silicone plasticizers. Silicone coatings have extremely high resistance to the deleterious effects of exposure to ultraviolet rays and can seal general surface wear very well. Nonetheless, it's important to understand that once a roof has been coated with siliconized fluid applied materials, future or successive applications with disparate materials are almost impossible from a perspective of bondability and compatibility.
Epoxy coatings contain epoxy resins formed from reacting bisphenol, a diglycidyl ether with amine or phenolic hardeners. Flexible epoxies use softening agents like nonyl phenol.
Other additives in roof coatings may include:
Solvents like glycol ethers to allow flow and application.
Fibers and fillers to reinforce the cured material.
Surfactants and dispersants to stabilize emulsified polymers.
Biocides and fungicides to prevent microbial degradation.
The picture below shows the recoating of historic ferrous metals above a flat roof system. This is not directly a part of the roof system and not a fluid applied roof coating, but accessory details like copings, flashings, and other metal transitions should be at least considered in a full roof assessment.
There are a variety of substrate roof materials and in most cases the specific chemical composition of each application may be selected and applied based on the specific substrate to which remediation or recoating is applied. The specific chemical composition of each application option is formulated to achieve desired performance properties once dried and cured on the roof surface.
Overall, fluid-applied restoration can be a cost-effective way to add decades of performance, delaying the need for full roof replacement. It can be an excellent option for refreshing and protecting aging flat roofs, highly valuable assets. Prioritizing regular maintenance helps extend the roof lifespan. Every incremental amount invested in roof upkeep and maintenance is still an expense, but when maintenance, upkeep, and repairs are done proactively, and intelligently, it can save thousands of dollars over the life of even a small roof.
Reach out and talk to us, we are happy to help where we can, either in consultation, analysis, condition surveys, maintenance, and roof repair or replacement. You can always email us info@structoflex.com.
Comments