Spray-On Attic Heat Barrier
Interior Radiation Control Coating Systems (IRCCS)
For Energy Conservation and Comfort Control
Specially Formulated to Lower Attic Temperatures and Save Energy
Because of their low emissivity and high
reflectivity, the LO/MIT Spray-on
Attic Heat Barriers are excellent replacements for foil or metalized plastic film radiant
barriers. In many cases, LO/MIT-II and LO/MIT-II MAX
are the only economical ways
to retrofit a radiant barrier to an existing structure since it may be safely applied in enclosed areas at a low
cost. LO/MIT-I is typically used in new construction only since
it is solvent-based and not suitable for use in finished structures that are
fully enclosed and not well ventilated. The LO/MIT coatings are classified by ASTM as Interior Radiation
Control Coating Systems (IRCCS) and offer the following unique features:
Low applied cost
(LO/MIT-II MAX, 0.15)
# C 1321-98 for Interior Radiation Control Coating Systems (IRCCS)
The LO/MIT Interior Radiation Control Coatings may be easily applied using airless or air atomization spray equipment or rollers. LO/MIT-I (IRCCS) is suggested for new construction since the building is normally wide open and ventilation levels are high. LO/MIT-II & LO/MIT-II MAX (IRCCS) are recommended for retrofit or enclosed structures where ventilation levels are lower. All products require adequate ventilation and it is suggested that operators wear goggles, respirators or masks, gloves and disposable or easily cleaned full body covering during application. Ambient temperature should be above freezing for application.
When applying to the underside of roofs, spray the entire radiating surface (This includes the flat decking areas as well as the rafters). Support beams are not necessary to coat, but coating sidewalls and gable ends will offer additional heat protection. Roof sheathing may also be pre-coated while still on the ground and stored (painted sides together) for future use. This is a very economical way to apply LO/MIT-I since the sheathing can be placed side by side and very little coating is lost to over-spray. When retrofitting LO/MIT-II or LO/MIT-II MAX to existing buildings, spray application is suggested since the presence of roofing nails may preclude roller application.
Coverage for interior application is normally 400 ft²/gallon when sprayed. LO/MIT-I (IRCCS) will skin dry within one minute after application. Drying to touch will generally occur within 15 minutes to 1 hour depending on ambient temperature and humidity. LO/MIT-II & LO/MIT-II MAX (IRCCS) will skin dry within 10 to 15 minutes after application. Full cure may take several weeks to six months or more depending on ambient temperature and humidity conditions present. Abrasion is usually not a problem on the underside of the roof, but the slow cure should be kept in mind when building sidewalls are painted.
Air atomization spray equipment should be kept at fairly low pressure (25-35 PSI) to lessen over-spray. Airless equipment should be operated at low pressure and a #613 self cleaning tip has yielded excellent coverage rates.
The LO/MIT coatings should be well mixed before use, and stirred or mixed as often as is practical during use to lessen pigment settling. 1 thin coat is all that is required for maxium efficiency.
LO/MIT Spray-on Attic Heat Barriers MUST face a minimum 2" airspace. The coating cannot be sandwiched between two different substrates. Insulation directly adjacent to the LO/MIT surface (such as in a finished attic or cathedral ceiling) should be backed off using 2" air baffles. The LO/MIT surface may not be painted over, tinted or adjusted in any way.
MORE INFORMATION
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LO/MIT-I Technical Brochure (solvent-based)
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LO/MIT-II & LO/MIT-II MAX Technical Brochure (water-based)
WHAT IS LO/MIT?
LO/MIT is a silver colored, non-thickness dependent, low "e" (emissivity) coating. When applied to non-porous building materials such as plywood, OSB or plasterboard, LO/MIT lowers their surface emissivity to 0.24-0.15 or lower. LO/MIT-I (solvent-based) and LO/MIT-II (water-based) have emissivities of 0.21-0.24. LO/MIT-II MAX (water-based) has an emissivity of 0.15-0.17. The LO/MIT coatings are classified by ASTM as Interior Radiation Control Coating Systems (IRCCS) and may be effectively used as Radiant Barrier insulation equivalents.HOW DOES LO/MIT WORK?
LO/MIT Interior Radiation Control Coating works by changing the emissivity of the surface where it is applied. Most building products such as plywood, brick, and plasterboard have high emissivities (0.70-0.95). When heated, they radiate most of their heat to cooler surfaces. LO/MIT can lower their surface emissivity to 0.24-0.15 or less, reducing their ability to radiate heat.
WHAT IS A RADIANT BARRIER (IRCCS)?
Heat flows in buildings occur in three ways: conduction, convection and radiation. Radiant Barriers and Interior Radiation Control Coating Systems address heat flows by radiation (whereas standard insulations only address convection and conduction heat transfer). Radiation is the transfer of heat by electromagnetic waves known as thermal radiation. Thermal radiation is a form of invisible light that travels through the air from a warm to a cool surface. Warm surfaces, such as roof decks warmed by the sun, will radiate or emit their heat to cooler interior building surfaces. A Radiant Barrier or IRCCS is a low emissivity surface placed in the path of thermal radiation that blocks or reduces that heat transfer. ASTM defines an "IRCCS" as a material having an emissivity of 0.25 or less. A "Radiant Barrier" as defined by ASTM has an emissivity of 0.10 or lower.
WHAT IS EMISSIVITY/EMITTANCE?
Emissivity or thermal emittance is the ability of a surface to radiate or emit energy in the form of long wave electromagnetic radiation. It is represented by a value from 0 to 1. The closer the value is to 1, the less effective the surface is at impeding radiant heat transfer. Wood has an emissivity of 0.72. Thus, when wood is heated above the temperature of surrounding surfaces, it will tend to transfer 72% of its heat energy by radiation. LO/MIT, when applied to most non-porous surfaces, will decrease the surface emissivity to 0.24-0.15 or lower, allowing as little as 15% of the heat energy to be transferred by radiation.
WHERE IS THE AIRSPACE WHEN USING LO/MIT?
To function effectively, the low emissivity surface of a Radiant Barrier or IRCCS must face an airspace of 2" or greater. A Radiant Barrier or IRCCS will not function if sandwiched between two solid surfaces. LO/MIT, when installed on the underside of roof decking, normally faces downward into the attic, an airspace substantially larger than 2". If insulation is installed in the cavity formed by the roof trusses and roof decking (as in a cathedral ceiling or finished attic), at least 2" should be allowed between the top of the insulation and the LO/MIT surface.
DOES LO/MIT ADVERSELY EFFECT ROOF SHINGLES?
Absolutely not! LO/MIT has never caused shingle damage in any installation. Extensive testing at the Florida Solar Energy Center has shown that the use of a Radiant Barrier or IRCCS results in, at most, a 2-5 degree rise in shingle temperature. Please read this article for more information about the effect on shingles with use of a Radiant Barrier/IRCCS on the underside of the roof.
DOES LO/MIT DEGRADE OVER TIME?
Unlike some insulation products, LO/MIT does not lose its effectiveness over time. Test samples installed experimentally over 25 years ago still have the same emissivity levels today, as they did when originally installed. There is no maintenance or recoat required for the life of the roof deck. LO/MIT is not susceptible to tearing and will not delaminate over time.
WHAT IS THE COVERAGE RATE FOR LO/MIT?
When applied with airless sprayers, coverage for LO/MIT on plywood is roughly 400 square feet per gallon. On OSB or particleboard, coverage is about 450 square feet per gallon. Be sure to spray all radiating surfaces including the flat decking, rafters, and any sidewalls or gable ends for best results.
WHAT IS THE RECOMMENDED APPLICATION METHOD FOR LO/MIT?
Spray application using standard airless or air atomization equipment. If airless, a #613 self-cleaning tip is recommended. If air, use a nozzle suitable for a low viscosity product and try to keep the gun pressure reasonably low (25-35 PSI) to lessen over-spray. A pump type insecticide sprayer may also be used, however, coverage rates will suffer. Be sure to check your sprayer for suitability with solvents if spraying LO/MIT-I.
IS LO/MIT PERMEABLE TO WATER?
Yes! LO/MIT allows water vapor to permeate, and does not trap water vapor within roof decks or sidewalls. If the roof were to develop a leak, the moisture will pass through LO/MIT, allowing the problem to be easily identified and repaired. LO/MIT will also not delaminate when re-roofing nails are put through the roof decking. These are major advantages for LO/MIT over other Radiant Barrier products, as the homeowner can avoid these potential problems in the attic.
CAN LO/MIT BE USED ON SIDEWALLS?
Yes, but LO/MIT is normally more effective when used under roofs. Low emissivity surfaces become more effective in controlling radiant heat transfer as the temperature of the radiant heat source increases. Roof surfaces are generally much hotter than sidewalls. However, in warm climates and where no insulation is used in sidewalls, LO/MIT can substantially help increase interior comfort levels.
CAN LO/MIT BE USED IN VENT-SKIN CONSTRUCTION?
Yes. In vent-skin roofs, LO/MIT should be applied on the underside of the outer roof skin facing down into the vent channel. On vent-skin sidewalls LO/MIT should be applied on the inside of the outer skin facing into the vent channel.
CAN LO/MIT BE USED WITH RADIANT HEATING SYSTEMS?
Yes. It is an effective heat reflector when used behind wood stoves or on walls/ceilings adjacent to ceiling mounted radiant heaters in commercial applications.
IS ATTIC VENTILATION IMPORTANT?
Very! Radiant Barriers and IRCCS only control radiant heat loads. Good attic ventilation helps control convection loads. Together they raise comfort levels and lower cooling costs. Venting to allow 2.5 air changes per hour should be specified as a minimum.
DO RADIANT BARRIERS (IRCCS) LOWER HEATING COSTS?
Yes, but only modestly. They are most effective at lowering cooling costs.
DO RADIANT BARRIERS (IRCCS) HAVE AN "R" VALUE?
No. R-values apply only to solid insulation or to insulating systems that control heat flows other than radiation. When LO/MIT is installed with R-19 insulation, the combination yields a total R-value of R-34 for heat influx. In this example, LO/MIT has an "apparent" R-value of R-15 because it improves the efficiency of the current insulation by making it cooler. Because of the potential increase in R-values for cooling calculations, builders may want to consider dropping A/C tonnage requirements when using LO/MIT.
IS LO/MIT A "LOW VOC" COATING?
Yes. LO/MIT-II and LO/MIT-II MAX are water-borne, low VOC emulsions that can be safely sprayed in enclosed spaces, such as attics. LO/MIT-II and II MAX meet the standards set forth by the California EPA Air Resources Board's Architectural Coatings Program regarding VOC limits. Please see MSDS for more information. Always be sure spray area is well ventilated and proper protections are used for the applicator including coveralls and respirators.
DO YOU HAVE ADDITIONAL QUESTIONS?
Contact our
Technical Services Department at:
Phone: 609-883-7700
Fax: 609-883-5489
Email: info@solec.org
Pictures and Descriptions of
Installed Projects
The Florida House
The Florida House Learning Center, located in Sarasota, Florida, demonstrates appropriate design strategies and technology for hot, humid climates. The house is a "traditional" model featuring cost effective and affordable energy conservation methods through "off-the-shelf" technology including solar domestic hot water heating and the application of LO/MIT on the undersurface of the roof.
Jennings-Pearman Energy Division,
Venice, Florida
The Resource Conservation House
Located in the NAHB Research Park in Gaithersburg, Maryland, this house demonstrates energy efficiency, recyclable materials and solar technology with an emphasis on enhanced durability and low maintenance costs. The entire undersurface of the roof is coated with LO/MIT to lower air conditioning costs.
LO/MIT-I being applied to underside of galvanized roof in chicken house at University of Georgia, Athens, GA. LO/MIT-I is an excellent metal building insulation because it lowers interior radiant temperature, in this case, lessening heat loads and death rates during extreme summer heat.
Contrast between uncoated and coated (right side) underside of chicken house roof at University of Georgia. LO/MIT-I increases interior lighting levels and lowers radiant temperatures, making an excellent metal building insulation in agricultural applications.
LO/MIT installed on underside of wood deck metal roofed humane society headquarters, Naples, Florida. LO/MIT was also installed on the underside of the roof areas over the open air animal storage pens in the rear of the building to keep the animals cooler.
LO/MIT installed on underside of standard asphalt shingled roof of golf pro shop, Naples, Florida. Notice continuous ridge vent used to improve attic ventilation.
LO/MIT-II interior radiation control coating installed as a metal building insulation on the underside of the steel roof of a hardware supply building. Note that all supporting beams and purlins were also painted, raising interior lighting levels. Owner reported that interior temperatures were up to 20°F cooler after LO/MIT was installed.
Cordell
Lumber Co.,
Dublin, GA
LO/MIT-I applied to large glass windows above entry/exit doors to prevent heat influx into vestibule. Though LO/MIT blocked the light transmission, vestibule temperatures dropped by 20+ degrees F.
Sands Expo and
Convention Center
Las Vegas, Nevada
The Lifestyle 2000 House
Located in the NAHB Research Park in Gaithersburg, Maryland, this house demonstrates energy conservation and reduced maintenance costs through the use of concrete and masonry products. The entire undersurface of the roof is coated with LO/MIT to lower A/C costs.
LO/MIT shown being applied to underside of flat roof. Note use of extension wand on airless sprayer for ease of application.
Thermal Advantage,
Chandler, AZ
LO/MIT installed on underside of 15,000 square foot wood deck tiled roof fire station, Naples, Florida. The combination of LO/MIT and tiled roofs is an excellent method to increase comfort and lower cooling loads in hot climates.
Jennings-Pearman Energy Division,
Venice, Florida
LO/MIT installed on underside of wood deck tiled roof house. An excellent combination of light colored, high thermal mass roof with interior radiant barrier to keep attic cavity cooler and increase interior comfort levels.
LO/MIT applied to underside of roof decking on unique
Enertia superinsulated Aquarius 2 log home.
Enertia
Building Systems,
Wake Forest, NC
University of Texas 2002 Solar Decathlon Design Competition House
LO/MIT-II was spray applied to the underside of the metal roof panels, and the inside surface of the Hardy Plank siding, increasing the the roof R values +15 and the side wall R values +7 (for heat influx).
Integrity Energy Systems,
Austin, TX,
Phone: 512-331-9444
LO/MIT-I IRCCS spray-applied to steel sidewalls of large construction storage warehouse.
Integrity Energy Systems,
Austin, TX,
Phone: 512-331-9444
LO/MIT-I IRCCS Spray-applied to underside of steel roof decking and trusses in an ice hockey arena. LO/MIT also dramatically increases interior lighting levels.
Jensa Peinture,
Montreal, CANADA,
Phone: 514-389-6111