The interior comfort level of any building is highly dependent on the building insulation system. The reasons for using building insulation are many:

• Keep heat in, moisture in, cold out (in winter)
• Keep cold in, heat out, humidity out (in summer)
• Exterior moisture barrier (all buildings)
• Noise control (commercial and metal buildings)

Building insulation needs are similar in residential and commercial construction. The roof, walls, basement as well as between pipes and steel sheets are the common places for insulating against heat loss or for heat containment. Just as residential homes need to control their utility bills, so do businesses. Businesses need their commercial structures, such as metal buildings or steel buildings, to be as efficient as possible with the endless rise of energy costs. With properly installed insulation, businesses with large facilities or multiple facilities can see savings of hundred of dollars a month.

Heat flows from a hot or warm medium to a cold medium in three ways:

• By radiation from a warm surface to a cooler surface through an air space through infra-red heat rays
• By conduction through solid or fluid materials resulting from direct contact
• By convection, which involves the physical movement of air - warm air rises

Heat moves through wall cavities, between roofs and attic floors or between floors and basements by a combination of radiation, conduction, and convection with radiation being the dominant method of heat transfer. Research shows that control of radiant heat transfer is the core of heating/cooling climate control.

You can insulate against radiant heat! Traditional fiberglass insulation has no effect on radiant heat transfer. Estimates are between 80 and 90% of the radiant heat striking fiberglass will pass right through it. Aluminum foil reflective insulation, which can reflect up to 97% of the radiant energy that strikes it, has proven to be an outstanding radiant heat barrier.

All new buildings should incorporate a radiant barrier as part of the insulation system. The concept is simple: each unit of radiant heat energy that is reflected away from your building in summer, and each unit reflected back in during winter, means less operation of your heating and air conditioning systems, less wear and tear on your equipment, and less money you pay in utility costs.

Heat transfer will occur across any barrier when there is a marked heat gradient between two discernible areas. Hot air will naturally try to fill a cooler space and essentially "push out" the cooler air. Consequently, any area that is artificially cooled or heated will inevitably revert back to equilibrium with the space around it if left free to do so.

Insulation will not eliminate this process completely, but it will slow it to the point that the issue will cease to be detrimental to the operation of the building. When considering a large industrial complex that is heated or cooled by large climate control systems, the benefits of limiting the amount of work done by the HVAC system are apparent. The better the insulation, the less the equipment will work and the lower the energy costs will be.

Metal Frame versus Wood Frame Construction

The primary differences in insulation installation are between wood-frame and metal-frame buildings. When you insulate a metal-framed building, it is important to recognize that much more heat flows through metal studs and joists than through wood. Because of this difference, placing insulation between the wall studs, or between attic or floor joists, doesn't work as well for metal-framed buildings as it does for wood-framed buildings.

For metal frame walls, you will need to place an insulation sheet over the outside of the wall frame, between the metal framing pieces and your exterior siding similar to whole house wrap. If your attic has metal joists, you will want to place insulation between the joists and the ceiling drywall. The US Department of Energy warns that "It's important to recognize that even if you install the recommended level of insulation in a metal frame building, you will not necessarily get thermal performance as good as you would get from a wood structure with its recommended level."

R-Value, or Resistance, is the measure of a material's ability to stop heat flow. The US Department of Energy has raised their R-value recommendations for both metal frame and wood frame new construction buildings.

Source: US Department of Energy Insulation Fact Sheet.

Metal buildings have unique challenges that properly installed building insulation can address. The benefits of metal building insulation include:

Heat flow control

Unfortunately, like most metals, steel is a very good conductor of heat. In hot weather, steel framing and sheeting rapidly transfer the sun's heat into a building, and in cold weather they rapidly transfer heat out. Building insulation acts as a barrier to slow down the movement of heat, keeping it inside the building in winter and outside the building in summer. By controlling the rate of heat transfer through the building, insulation reduces energy consumption, resulting in lower fuel bills and a cleaner environment.

Noise control

Metal insulation greatly reduces the level of both exterior and interior noise. Use a fiberglass or rigid foam insulation in conjunction with reflective insulation for greater noise control.

Increased lighting efficiency

Metal building insulation is frequently installed with surfaces that are visible from the inside. Reflective building insulation provides a bright, attractive wall and ceiling treatment that acts as a reflector to increase lighting efficiency. Aluminum foil reflects light, making it easier to illuminate the building interior. Installing insulation with a white facing makes it even easier to illuminate the building interior as white reflects light very efficiently. In addition to light reflectivity, a white facing can provide an aesthetic appearance. A nice example of a white faced reflective insulation is Foil-Fiberglass-Vinyl. Using a multipurpose product like this combines insulation, radiant barrier, and vapor barrier in one making it ideal for either commercial or residential applications alone or in conjunction with fiberglass.

Condensation prevention

Condensation can be a more significant problem in a metal building than temperature control. Moisture from rain, groundwater, humidity and human activity like washing, cooking and breathing creates the potential for several problems in metal buildings. First, the presence of water or ice in the insulation seriously degrades both the thermal performance and service life of fiberglass, paper, wool and other traditional insulation materials. Second, water in contact with metals contributes to corrosion and lowers the service life of the building. Third, collection of water can lead to dripping, staining, mold, mildew and odors.

All of these problems can be solved with a properly installed insulation/vapor barrier system. Even in only moderately humid climates, condensation can cause serious problems in an unprotected metal building. To avoid this problem, adequately ventilate the building and install a vapor barrier even if you do not plan to insulate.

Use reflective foil insulation - it will never get wet and have to be replaced like fiberglass batts. Reflective insulation acts as a vapor barrier or vapor retarder by limiting the passage of water vapor thereby preventing condensation within the insulation or on the interior surfaces of the building.

Follow this link to a comprehensive article on the problems and solutions to condensation in wood frame homes: Vapor Barrier Insulation

Common places to install reflective building insulation include walls, roof, ceiling, attic, floor, crawlspace, foundation wall, pipes and ducts.

For new construction of a metal building:

• Install between framing and sheeting
• Place double-sided tape on frame
• Roll out insulation over frame
• Allow insulation to sag slightly (approx 1 inch) to create air space
• Attach your sheeting as if the insulation wasn't there

To Retrofit an Existing metal building:

Use a combination of glue, tape or screws to attach to side or underside of metal beams. You may install between beams or run opposite direction over beams to avoid having to cut (this is the method to create a vapor barrier). Reflective insulation is most effective when incorporated with a ¾-inch or more airspace on at least the outer side of product.

Click here for comprehensive installation instructions using reflective insulation as Metal Building Insulation.

Cavity wall installation in a metal building:

• Stick the insulation to the metal studs with double faced tape. Just stick it temporarily prior to the installation of the metal strapping.
• Install the metal strapping and drywall following the manufacturer's recommendations

Click here for comprehensive installation instructions using reflective insulation in the Cavity Wall of a metal building.

Concrete block wall installation:

• Attach the rigid insulation to the blocks
• Screw the first metal strapping to the wall through the rigid insulation
• Stick the insulation to the metal strapping with double faced tape. Just stick it temporarily prior to the installation of the wood strapping
• Seal all seams with aluminum tape
• Install the second strapping and drywall following the manufacturer's recommendations

Click here for comprehensive installation instructions using reflective insulation for concrete block construction.

Concrete foundation walls:

• (With Existing Insulation) You may want to install (if it's not there) a mechanical attachment system.
• (With No Insulation) Install, horizontally, against the concrete wall the first wood strapping every 16" with the asphalt felt behind it.
• Staple the insulation with white side facing the concrete wall at every 16" without overlapping the material. Use a Foil-Bubble-White Poly insulation with concrete walls and under concrete slabs.
• Seal all the seams with aluminum tape.
• Install the second wood strapping or stud perpendicular to the first one.
• Install the drywall following the manufacturer's recommendations.

Click here for comprehensive installation instructions using reflective insulation to insulate concrete foundation walls.

Barrier to radon gas:

Using reflective insulation in the floor and in the walls is very efficient in areas having radon gas problems. It is cheaper than a lead barrier, a perfect vapor barrier and has thermal resistance properties.

Click here for comprehensive installation instructions using reflective insulation to insulation concrete foundation walls.

Pipes and ducts:

In addition to building insulation, you will need insulation for the air handling systems and PVC pipes. Wrapping heating and air conditioning ducts, as well as pipes, prevents condensation, reduces noises and vibrations. Using reflective insulation for pipe wrap is equivalent to 1" of fiberglass and is not affected by moisture and water.

Click here for comprehensive installation instructions using reflective insulation as Duct or Pipe Wrap.

US Department of Energy
Building Envelope Research
OakRidge National Laboratory
Insulation Fact Sheet

North American Insulation Manufacturers Association
Metal Building Insulation Applications Information
www.naima.org

Steelbuilding.com Inc.
Steel Building Insulation
Reflective Foil in Steel Buildings
Fiberglass in Steel Buildings
steelbuilding.com

Understanding and Using Reflective Insulation, Radiant Barriers, and Radiant Control Coatings
Reflective Insulation Manufacturers Association, April 1999