Cool building coatings are “The most effective least costly option to save energy in low slope roofing in residential, commercial and industrial buildings”. – RCMA
The thought of never having to buy a new roof is tempting. But it sounds more like wishful thinking than anything realistic. Well, ok. Everything has it’s breaking point and nothing lasts forever. But let’s say your roof deck is in pretty good shape. No serious problems. A liquid applied roof coating has a number of benefits over a single ply membrane system.
1. Monolithic membrane. No seams to leak. That’s one of the reasons for yearly inspections. When you have one solid piece knit together there is less likelihood of leaks.
2. Repairs. Coating repairs are: 1) quick 2) inexpensive and 3) easy. For small repairs all you need is more coating. If there are larger repairs needed, mesh fabric is sometimes needed.
3. Durability. Warranties are often measured in the thickness of the products. Some products a stupid thick with only a 20 year warranty. You end up paying for more material. Most roof coatings shouldn’t need to be more than 20 mils DFT per application. Some systems go up to five products depending on what’s being done. Let’s say three is average. Base coat with or without embedded poly mesh fabric, mid and top coat. With an minimum of 10 mils DFT per coat, 20-40 mils is common in many coating systems.
4. Cooling. The difference can be substantial between a typical reflective (cool) roof coating and a thermal barrier coating when you compare a decade of energy bills. A thermal barrier coating like mine will save an additional 30% on energy costs, according to an independent test. That’s just for exterior use.
5. Longevity. How long can you keep adding more coating? For as long as your roof can hold it. The roof can go 10+10+10+10+10+10 years, or more. That’s not quite forever but it will get you through your career.
Myth busters: “Heating Penalty” debunked
A May 31, 2016 study published by Concordia Univerity in Montreal, Canada in Energy and Buildings confirms that, contrary to the belief that cool roofs won’t work in colder climates, they actually provide net energy — and monetary — savings. “Using a cool roof on a commercial building in cold climates is typically not suggested based on the presumption that the heating penalties may be higher than the cooling savings,” says Hashem Akbari, professor in the Department of Building, Civil and Environmental Engineering and the study’s senior author. “Our research shows that any improvement to a roof that limits the summertime solar heat gain actually results in energy-cost savings for the building owner, as well as a reduction in the building’s overall environmental impact.”
They found that cool roofs for the simulated buildings resulted in annual energy expenditure savings in all municipalities.
A cool roof on a new, medium-sized office building would save four dollars per 100 square metres in Montreal, $10 per 100 square metres in Toronto and $14 per100 square meters in Milwaukee and Anchorage.
The research also showed that cool roofs can reduce the peak electric demand of the retail buildings by up to five watts per square metre.
“Our study proves that cool roofs for commercial buildings are a net saver of energy in all climates that use air conditioning during the summer,” says Akbari.
“In cooler climates, installing cool roofs may even prevent buying an air conditioner altogether. Even in non-air-conditioned buildings, cool roofs improve comfort duringhot summer days.
Should I replace or restore my roof?
Sometimes there is no saving a roof. There are just too many things going wrong to justify keeping it. But often times a roof can be restored and brought back to life with a roof coating. Most coatings are water proof and offer a good bit of water resistance. Sometimes the source of a leak is not the roof itself. It could be condensation from an AC line 100′ away. Maybe a drainage line sprung a leak or there is a problem with the flashing. Finding the real culprit is real important. Once the source of the leak is confirmed to be the roof, a cool roof coating can do more than stop a leak. The Roof Coatings Manufactures Assoc has a long list of benefits to cool roof coatings. Here are my top ten.
Top ten reasons to consider cool roof coatings
1. Lower cost roof in materials, installation and maintenance. Paint on a new roof for half the cost of typical remove and replace.
2. Better budget management due to predictable life extension of the roof through re-coating the surface rather than replacing it.
3. Reflective roof coatings lower opperating costs by lowering roof surface temperture about 50%, which reduces indoor tempertures 6-9 degrees, reducing AC runtime.
4. Lower AC runtime is especially effective at peak electrical demand times when energy is most expensive. Lowering peak demand energy use may qualify for utility insentives, tax credits or rebates.
5. A healthier building. Reducing exterior surface tempertures reduces vapor drive and the likelihood of mold or mildew in the walls.
6. Reduces cost and maintenance due to thermal bridging and thermal shock.
7. Increases the effective “R” value of insulation by keeping the wall cavity dry and reducing the amount of heat to resist.
8. They are environmentally friendly because they reduce landfill materials, save energy, reduce the carbon footprint of the building and minimizes the overall environmental burden.
9. Cool roof coatings result in reduced overall roof life-cycle costs.
10. ROI is building and product dependent, but often is within 5 years. Once a coating is applied it forms a monolithic membrane without seams that leak. Maintenance is simple and less expensive that typical roofs.
Don’t call a roofer
Don’t get me wrong, roofers are great when you need them. Like when you need to track down a leak. But most roofers are not up to speed on roof coatings. They do the best they can and let you pick from the two or three options the local roofing supply store carries. IMHO you should call a coatings expert. After all, you are “painting” on a new roof. Let the roofers roof and the painters paint your way to a better building. I have an extensive knowledge of coatings available and the differnt chemistries used. I also have a good working knowledge of building envelope design and performance.
Building envelope optimization
Cool building coatings on your walls have the same benefits as your roof. If you are thinking of a deep energy retrofit or upgrades in energy efficiency, consider this. Using a cool coating on your exterior walls is similar in effect to installing an EIFS. Water resistance, moisture resitance, air resistance, heat resistance and a long lasting durable exterior. A semi permeable coating allows the building to breath enough to dry safely while preventing water loading into the stucco or other surface.
Heat reduction reduces vapor drive, thermal bridging and thermal shock.
You end up with better performing walls, healthier walls, better IAQ, and lower maintenence overhead.
This method of energy conservation was tested by the Energy Conservation Assistance Program on July 19-20, 2004 in Denver, CO. Two identical 48sf test building were constructed using standard building materials and techniques. Walls and roofs of both buildings were painted the same color white. One with a normal exterior paint, one with Super Therm cool roof coating. The building coated with Super Therm out performed the other building by using 30% less energy. On a cloudy day. I can send you the full report.
I understand the “white blight” concerns. Super Therm can be tinted to hundreds of light and midtone colors with traditional colorants or infrared reflective pigments. I also have a flat clear nano-tech heat reducing coating that works quite well. Especially for concrete or tile, roof or walls.
Cool building coatings are a proven and reliable energy conservation measure. Coating a commercial roof often saves 10% – 20% in energy costs by reducing the indoor air temperature by 6 – 9 degrees. ROI is coating and building dependant. Talk to Tim @ 719.641.5043 or email him at firstname.lastname@example.org for a free report.
Cool roof and building coating
Super Therm cool roof and building coating is a water borne combination of high performance aliphatic urethanes, elastomeric acrylics, and resin additives which produces a tough yet flexible coating. Designed for performance and durability, Super Therm contains 4 unique ceramics which block up to 95% of solar heat entering a structure. Super Therm is a low permeability flexible membrane that can greatly reduce expansion and contraction of a roof. It also prevents corrosion and surface deterioration. Can be applied to metal, concrete, wood and masonry by spray, brush and roll. Apply no less than 17 mills wet. Typically used as a system with products listed below.
- Solids:69% by weight, 58% by volume
- Repells 95% of all light waves, UV to Infrared
- 30-60 minutes to tack free at 70F
- Overcoat: 2 hours @ 70F and 40% RH
- Full cure 21 days
- Weight 11.88 lbs/gallon
- Viscosity: 105-110 KU
- Minimun surface temp when applying: 40F
- Maximum surface temp to apply: 150F
- 16 ASTM tests passed. See TDS for details.
In a 15 year retest of Super Therm performance characteristics, a sample was taken from a low slope metal roof in western Kansas. The test results show a 73% solar reflectance, especially good since the Energy Star initial Soloar Reflectance Index was 80%. Typical SRI depreciation after 6 months is 10% – 15%. Super Therms 7% depreciation after 15 years is excellent by any standard.
A water proof one part elastomeric hydrocarbon rubber compound loaded with ceramic pigment for strength. It can be applied over a pressure washed substrate of TPO, EPDM, PVC, wood, concrete and metal with appropriate primer, if needed. Specs:
- Solids: 63% by wieght, 50% by volume
- One component
- VOC’s: 3.5lbs/gal or 419 grams/liter
- Viscosity: KU 141
- Tensile Strength: 1765
- Elongation: 512%
- Permeance: 7.3
- Tear resistance: 351 lbf/in
- Fungi resistance rating: “0”
- Can be applied to damp or wet surfaces
- Application Temps: Max: 150°F, 65°C / Min: 50°F, 10°C
- Passed ASTM 6083
- Can not be applied directly over foam. Use Super Therm to seperate.
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- 100% SILICONE. The unique chemistry of GacoRoof offers peace of mind for a lifetime! It outperforms and outlasts acrylic, urethane, asphalt and Hypalon® coatings.
- NO PRIMER REQUIRED. GacoRoof will adhere to most surfaces without a primer including built up roofs, cap sheet, metal, modified bitumen and sprayed polyurethane foam.
- REMAINS PERMANENTLY FLEXIBLE. GacoRoof will stay flexible and maintain adhesion, even under permanent ponding water or snow pack. Other coatings become brittle and begin to degrade over time.
- WITHSTANDS PERMANENT PONDING WATER. GacoRoof is an excellent choice for flat or sloped roofs. Extremely durable, GacoRoof will not soften, bubble or degrade under permanent ponding water.
- NON-SACRIFICIAL. GacoRoof is unaffected by harsh UV rays and temperature extremes.
- PREVENTS COSTLY TEAR OFFS. By recoating your weathered roof with GacoRoof, you not only extend the life of your roof, you avoid the need for a time-consuming and costly tear off.
- 50-YEAR LIMITED MATERIAL WARRANTY. All GacoFlex Coatings Carry a 50 Year Limited Material Warranty.
Rust Grip rejuvenates rusty metal and gives new life to metal, concrete or wood surfaces. It simplifies steel coating operations because it is “surface tolerant” and UV stable. It’s primer, intermediate and top coat in one. Our patented formula penetrates deep within the surface through micro cracks, rust or pits and expands as it dries to a smooth hard surface. It soaks through multiple layers of old paint while anchoring into the substrate and seals out air, moisture and contaminates while forming a tough, high tensile strength aluminumized surface with high impact resistance. Rust Grip is an easy to use single component moisture cure polyurethane coating. It also passed ASTM E 1795 test for a bio-hazard encapsulent able to encapsulate lead based paint, asbestos and other bio hazards occasionally found on old metal roofs. Specs:
- Class A fire rating
- Solids: By weight62.2%, By volume 51.4%
- Tensile Strength 6,780 psi after 3 weeks
- FM, USDA, ABS, US Navy approved
- Salt water test (ASTM 117B) 15,000 hrs perfect score
- Resistant to mildew, chemicals, acid, alkali
- VOC 380 g/l, 3.17 gal/lb
- Maximum surface temperature at application: 150°F, 65°C
- G85: Prohesion over rusted metal
- Superior adhesion
A single component coating combines high performance urethane and elastomeric acrylics in a water borne formulation. The coating is designed using high quality elastomeric resin system for long life and weathering, and ponding water resistance, with good dirt release. Can be used as a one coat system over most types of roofs or as a top coat over Super Therm. A value engineered solution for tight budgets. Specs:
- Solids: 51.7% by weight, 52.89% by volume
- 30-60 minute tack free at 70F
- Full cure in 21 days
- Cures by heat and evaporation
- Weight: 10.5 lbs/gallon
- VOC: 67 grams/liter
- Viscosity: 105-110KU