Any coating is only as good as the surface to which it is applied. If the underlying surface weakens, peels, splits, cracks or lifts, then the surface coating will undoubtedly fail as well. It is very important to determine that the underlying layers and substrate are in sound and stable condition. The underlying layers must be fully adhered to the substrate, and the substrate must also not be loose or deteriorated.
It is common practice to regard "preventative maintenance" as layer upon layer, year after year of tar, asphalt or aluminized asphalt coatings. Many coatings, however, are not formulated for long-life expectancy, so coating and re-coating can actually contribute to future unseen problems.
As the layers build up, the older bottom layers continue to age, either drying out or softening and losing adhesion to their surrounding layers. The underlying layers will continue to deteriorate although the surface still looks good. When these sub-layers let go and the surface coating still appears fine, it is the sub-layers and not the surface coating that has caused the failure.
Moisture penetrating these sub-layers can do a great deal of hidden damage. Repeated "wetting" and "drying" cycles cause materials to weaken and loose their adhesion. Some products soften and deteriorate, while other materials turn hard and brittle. Along with the constant stress and movement that all buildings undergo as the weather changes, it is quite easy to see why buildings can experience so many moisture problems.
It is often difficult to determine the exact soundness of a surface, so it is very important to begin by looking for any visual evidence of moisture, patterns of stress and movement, or soft, spongy areas that may be unsound. Check around any openings for moisture saturation or separation.
A coating should not be considered a substitute for an exterior structure or system and may not be able to remedy or overcome serious flaws, problems or excessive stress. TKO Waterproof Coatings, LLP does not recommend the use of its products on surfaces with widespread or excessive damage, structural defects or other serious conditions. These and other similar situations may require removal and replacement of building components.
Bleed-through is the diffusion or movement of colored matter through a coating. It can be a problem on tar or asphalt surfaces and is characterized by a brownish discoloration of the coating when applied over a soluble or unstable tar or asphalt base.
Tar and asphalt products are soluble by nature, which means they can be dissolved or made liquid. The degree of solubility varies with each individual product, and even with each individual batch of a particular product. Solubility is also affected by exposure to heat and solvents. The more soluble a product is, the more sensitive it will be to these factors, and the more likely that migration of colored matter to the surface will occur.
Bleed-through is a strong indication that the tar or asphalt base is readily soluble and unstable, and may therefore affect the coating's performance. TKO Waterproof Coatings' patching and coating products may not withstand the expansion and contraction of tar or asphalt's soluble compounds.
To effectively "block" and prevent bleed-through from coming through lighter colored coatings over stable, non-soluble surfaces, coat the entire surface area thoroughly with Primer-kote. Allow the primer to dry fully before application.
Rust is the oxidation of iron and steel in the presence of water. Since iron and steel are made from naturally occurring forms of iron oxide, moisture is all that is necessary to cause the formation of rust, and rust cannot exist without it.
Moisture can come from both inside or outside, so be sure to explore every possibility during the initial inspection. To completely eliminate a rust problem, the exposure to water must be stopped and the existing rust must be thoroughly eliminated or coated with a rust-inhibiting agent.
When using Metal 1-kote or Metal-Patch on rusty metal surfaces, remove all flaking and loose material. Loose rust particles that are not removed may be trapped in the Metal 1-kote or Metal-Patch and could migrate through the coating, causing rust discoloration. Rust that is secured to the surface does not need to be wire-brushed, scraped, removed or primed. Once the surface is free of any flakes or loose particles, sweep, brush or power-wash to make sure the roof is thoroughly clean and free of rust residue. Metal 1-kote and Metal-Patch contain a unique formulation of resins and polymerized Soya oil that "bite" into metal surfaces much like fingers on a hand. Therefore, no priming is necessary when using Metal 1-kote or Metal-Patch over rusted surfaces.
Use extra care when coating heavily pitted and rusted metal to prevent voids, thin areas or pinholes that may allow moisture penetration. Uncoated rusty areas may bleed and stain newly coated sections of the roof. For best results, coat 100% of all rusted areas on roof and surrounding surfaces to prevent staining.
Note: Rust on the reverse side of roofs or walls must be treated separately when coating with Metal 1-kote. Failure to treat both sides of a rusting surface may allow further rust or damage to occur.
Note: Since TKO Waterproof Coatings is not responsible for surface preparation and product application, it cannot be responsible for final results when coating rusted metal surfaces.
Completely remove all rust to ensure full adhesion of Tuff-kote, Tuffide, or Roof-kote to metal surfaces. Rusted areas should be wire-brushed, scraped or sanded to remove loose flakes and as much surface rust as possible. Thoroughly sweep and clean each area to completely remove dust, grit or rust particles. New, bare and unpainted galvanized metals require a special primer. Consult metal manufacturer or paint store for best recommendations.
Buildings take a tremendous beating from the weather and are therefore subject to constant stress and movement. Temperatures from both inside and outside cause all building materials to expand and contract on a daily and seasonal basis. Freeze/Thaw cycles create extra stress and movement, and in many areas, settling and underground shifting causes movement as well. Even above ground vibration and shocks from construction, heavy traffic and extreme weather can shake the sturdiest of structures. The result is that areas where stress and movement is concentrated weaken over time, ultimately leading to breakpoints of many types.
Determine the effects that weather extremes have on structures during the initial inspection. Cracks, splits and separation are strong evidence of movement, and are obvious avenues for water penetration. Extreme weather will vary the degree of separation and penetration of water so moisture may accumulate slowly and be absorbed by porous materials such as wood or insulation. Trapped moisture in the decking, substrate or insulation may not be detected during a standard visual inspection.
Note: If there is reason to believe that moisture may be trapped with the roofing system, consult a roofing professional for a further diagnosis. TKO Waterproof Coatings cannot be held responsible for damage incurred as a result of trapped or hidden moisture. Applying a new membrane or waterproof coating puts pressure on the saturated underlying material, forcing water downward like a sponge. Water damage to the interior could temporarily intensify as moisture seeks an exit. Be sure that appropriate ventilation exists for the space beneath the surface.
Mold and mildew are living organisms that grow on the surface of many common materials, including paints and coatings, wood, metal and masonry. They can grow almost anywhere, but will flourish in warm, damp and dark environments. Mold and mildew generally appear as a powdery film or as spotted, stained, discolored areas that cannot be removed with common soap and water. They must be properly treated and removed, as growth will continue and spread if left unchecked.
Fungicide cleaners or liquid bleach are effective for removing mold and mildew. Scrub the affected areas with the proper solution and a stiff brush, a heavy sponge or cloth. Be sure to wear rubber gloves and protective eye-wear to avoid skin or eye injury. Once the mold or mildew has been completely removed, rinse the surface with water and allow it to dry thoroughly. Treat all affected areas with a suitable inhibitor to prevent any recurrence prior to coating or patching.
Mold and mildew may be a problem in warm, damp climates or where sun and air do not reach. If TKWC products have mold or mildew on the surface, they can be easily cleaned with a bleach solution or fungicide. Water-blasting is also effective, and can be used to remove mold and mildew as well as dirt and other contaminants.
For further technical support, contact our Technical Services Department via phone (815.338.2006), fax (815.338.9105) or email (tech@tkocoatings.com).
General Information & Application Guidelines | Five Basic Steps to Roof Repair | How to Avoid Common Roofing Problems