Insulation materials come from different sources, such as minerals, plant fibers, animal products, and synthetic compounds. As with many engineering decisions, each material has advantages and disadvantages that must be considered in selection. insulation for buildings .
This article provides an overview of the main options on the market and how they work in real projects. There are insulation materials that are no longer used, but can be found in older buildings – an example is insulation with asbestos content, which has been banned.
Make sure your building has adequate insulation and reduce your energy costs.
Fiberglass
Fiberglass is one of the most popular insulation materials, made by weaving together fine strands of glass. It is mainly made from recycled glass.
Characteristics:
-Minimizes heat transfer
-Non flammable
-R-values range from R-2.9 to R-3.8 per inch
-Low cost
-Environmentally friendly
-Does not absorb water
-Can be dangerous for installers, requiring special protective equipment. Small glass particles can cause damage to eyes, lungs and skin.
-Loose fill insulation is applied using an insulation blowing machine
Available in:
-Blankets (blankets and rolls): fiberglass batts can be found in medium or high density, with higher R-values than standard batts
-Loose and blown fill
-Blow-in Blanket System (BIBS): a variation of loose-fill insulation that is dry, and testing has proven a higher level of insulation than other types of fiberglass
-Rigid plates
-Duct insulation
-Rigid fibrous insulation
Mineral wool
Mineral wool refers to two types of insulation material:
- Rockwool, made from basalt or diabase
- Slag wool, made from blast furnace slag from steel mills
Characteristics:
-Contains an average of 75% post-industrial recycled content
-No additives needed to make this fire resistant
-Not recommended in extreme heat environments
-Non flammable
-R value ranging from R-2.8 to R-3.5
-Environmentally friendly
-Does not melt and is non-combustible
-Moderate cost
Available in:
-Blanket (blankets and rolls)
-Loose and blown fill
-Rigid fiber or fiber insulation
Cellulose
Cellulose is made from recycled paper products, mainly newspapers. During the manufacturing process, paper is first divided into smaller pieces and then fiberized. Cellulose is one of the most environmentally friendly forms of insulation and is available in loose-fill and blown-in versions.
Characteristics:
-Environmentally friendly
-Most of its content is recycled (82-85%)
-Inhibits air flow
-Borate mineral is added to ensure fire and insect resistance
-No moisture barrier required
-R values range from R-3.1 to R-3.7
-Excellent product to minimize fire damage
-Due to its compactness, it contains almost no oxygen inside
-Can cause allergies
-Requires skilled workers for installation
-Moderate cost
Polystyrene
Polystyrene is a colorless and transparent thermoplastic. Polystyrene insulation is available in several versions:
- Molded expanded polystyrene (MEPS), commonly used in foam boards and as small foam beads.
- Expanded polystyrene (EPS), made from small plastic beads fused together
- Extruded polystyrene (XPS), is a cast material that is pressed into sheets, also known as Styrofoam
Characteristics:
-Low cost but not environmentally friendly
-Flammable, needs to be coated with a fireproof chemical
-Light
-Tends to accumulate static electricity
-Can be difficult to control
-Thermal drift or aging occurs over time – R-value depends on density: expensive XEP has an R-value of R-5.5, while EPS offers R-4
-Waterproof
-Excellent acoustic and thermal insulation
-Smooth surface
Available in:
-Loose fill (small beads)
-Insulation of concrete blocks and insulating concrete blocks
-Insulating concrete forms (ICF)
-Structural insulating panels (SIP)
-Foam board or rigid foam
Polyurethane
Polyurethane is available in closed-cell foam and open-cell foam. Closed-cell foams have high-density cells filled with a gas (not HCFC), which allows the foam to expand. Open cell foams are not as dense and are filled with air, producing a spongy texture when applied. However, some low density varieties use carbon dioxide as a foaming agent.
Characteristics:
-High cost
-Not environmentally friendly
-Fire resistant
-Great acoustic insulator
-New foams use CFC-free gas as a blowing agent
-Light
-R-Value of R-6.3 per inch
-Contains low conductivity gas in its cells
-Thermal drift or aging only occurs in closed cell foams within the first two years after application. To slow thermal drift, a layer of metal foil and plastic coatings can be applied facing the outdoor space, creating a radiant barrier.
-Sprayed foam is cheaper than foam boards and has better performance. -Pulverized foams can expand quickly or slowly depending on user demands
-Resistant to water vapor diffusion
Available in:
-Foam board or rigid foam
-Sprayed foam and foam in place
-Structural Insulated Panels (SIP)
Natural Fibers
Many natural fibers have applications in building insulation. Some examples are cotton, sheep's wool, straw and hemp.
Cotton is available in batts and rolls and offers the following features:
- Consists of 85% recycled cotton and 15% plastic fibers
- Treated with borate (flame retardant and insect repellent)
- Minimum energy requirements for manufacturing
Sheep wool is also available in blankets and rolls, and has the following characteristics:
- Treated with borate to resist pests, fire and mold.
- Retains water, but repeated wetting and drying reduces the borate effect
Straw has been used as insulation since the 1930s. It is available in structural insulated boards or panels (SIP), which absorb sound and are typically 2″ to 4″ wide.
Hemp is not a common insulation material in the US, although it has comparable R-values to other types of fibrous insulation.
Polyisocyanurate
Polyisocyanurate or polyiso is a closed-cell thermosetting plastic similar to polyurethane. It contains a low conductivity HCF-free gas and can be foamed in place, which is cheaper and more efficient than using foam boards.
Polyiso undergoes thermal drift or aging in the first 2 years after manufacturing, but foil and plastic coverings can be applied facing outdoor spaces. This acts as a radiant barrier, stabilizing the R-value
Polyiso is available in the following formats:
- Foam board or rigid foam
- Sprayed foam and foam in place
- Laminated insulation panels
- Structural Insulated Panels (SIPs)
Cementitious Foam
As its name suggests, this insulation material is cement-based. It is non-toxic and non-flammable and is made from minerals extracted from sea water. Cementitious foam is similar to polyurethane foam and can be sprayed and foamed in place.
Phenolic foam
Phenolic foam is another type of insulation that is sprayed and foamed in place. It uses air as a foaming agent and can shrink up to 2% after curing.
What are insulation coatings?
Linings are coatings attached to insulation during or after the manufacturing process. Its main objectives are to protect the surface, hold the insulation together and simplify attachment to building components. Depending on the type of coating, it can also fulfill the following functions:
- Acting as an air and vapor barrier
- Flame resistance
- Aluminum foil, in particular, is also a radiant barrier
Some more common types of siding are kraft paper, white vinyl, and aluminum foil.
Insulation materials no longer used
Some insulation materials that were used in the past are now banned, unavailable or not used due to health concerns. Some examples are vermiculite, perlite and urea-formaldehyde.
Vermiculite and perlite were used to insulate attics before 1950, but are no longer used because they contain asbestos. These insulation materials were mainly available as loose fill or pellets.
- Contractors certified in handling asbestos required for removal of existing buildings
- They were applied by heating rock pellets until they burst
- Allowed mixing with cement
Urea formaldehyde is a sprayed foam commonly used in the 1970s and 1980s. However, due to inadequate facilities, many health-related lawsuits have occurred. As a result, urea-formaldehyde has been banned in residential buildings, but is still used in masonry walls in commercial and industrial buildings.
- Uses compressed air as a foaming agent
- Does not expand while curing
- Nitrogen-based UF takes longer to cure
- Water vapor can pass
- Does not contain fire retardant
Conclusion
The sheer number of insulation materials available can seem overwhelming. However, with professional engineering services, you can ensure your project has optimal insulation. A well-insulated building has lower heating and cooling expenses, since effective insulation minimizes heat gain during the summer and heat loss during the winter.
When effective insulation is combined with high-efficiency HVAC design, your building can dramatically reduce heating and cooling costs. Applying insulation is cheaper and simpler in new buildings as there is no need to disturb an existing construction. Developers planning a new project should keep this in mind.
