Choosing the best XX Century insulation material for your shipping container
There is a lot of ink used to write about insulating shipping containers
But, as of some of you already know me, I prefer to focus on unconventional and new materials, than in the more conventional and better know, like (EPS) expanded polystyrene, which is as you know a lightweight, closed-cell, rigid, plastic foam insulation material produced from solid beads of polystyrene.
The EPS beads are expanded and then molded into large EPS boards, then used in walls, roofs, floors, attics, crawl spaces, (EIFS) Exterior insulation and finish system, stucco, and architectural shapes.
EPS offers design flexibility, high R-Values for thermal insulation, superior dimensional stability, and resistance to moisture absorption and physical degradation.
EPS is the ideal, cost-effective and easy-to-use material in all types of buildings, from houses and offices to factories and schools. StarRfoam meets or exceeds the requirements of ASTM C578, Standard Specification for Rigid, Cellular Polystyrene Thermal Insulation.
Insulation should be in general designed to work year round, so it’s not just heat loss during the winter that you have to worry about. Thermal bridges can actually cause an increase in heat gain during the warmer months of the year, which can lead to overheating of the indoor space.
As insulation porpoise is to keep the indoor air temperature at a consistent and comfortable level, anything that puts it at risk will demand a higher monetary cost to compensate it.
You should look at Insulation is an investment, and not as a cost.
Blankets and Batts
Another common type of insulation are blankets and batts, available in different type of fibers, like mineral wool, plastic, cotton and sheep’s wool.
Which is the difference between blankets and batts?
If they are sold in a roll is called a blanket, and If they are sold in a bundle is called a batt.
Other types of insulation are made from fiberglass, which is glass fibers bonded with a thermoset resin.
When insulating a shipping container, it is better to use high-density insulation with a higher insulating value.
High-density type of insulation has more fibers per square inch and therefore delivers a higher R-value using less space.
Fiberglass batts must be be properly installed, as errors can cause gaps and voids between and around batts, and thereby creating thermal bridges thus deteriorating the insulation’s performance.
spray polyurethane foam (SPF)
Is another alternative to traditional building insulation.
It is better to use closed-cell polyurethane foam, which is virtually impermeable to air and the only insulation material that adds structural integrity.
Spray foam can be applied to internal and external walls and underneath the container and painted over.
SPF is the quickest method of insulation, ensures a seamless vapor barrier of insulation and also helps to prevent against corrosion and mold.
Moreover, it usually provides superior insulation values, is incredibly flexible, can be sprayed to fill up cavities and block any small holes. .
Structural Insulated Panels (SIPS)
Is another alternative to traditional insulation. This high performance building system of panels consists of an insulating foam core located between two oriented strand boards (OSB).
SIPS are extremely strong, energy efficient, cost effective, and can be fabricated to fit nearly any building design.
Being this said, and before entering into more materials description, I would like to emphasize that Insulating a shipping container is similar to insulating any other home with the difference that shipping container walls are made of steel, a very thin but high thermal and sound conductive material.
Steel shipping/cargo containers walls are made from 14 gauge, 0.075-inch corrugated sheet steel panels, with an R-value of approximately 0.0031 per inch of thickness, while the standard residential rough wall thickness in the USA is, 3 and 1/2 inches.
That’s the width of common lumber of 2 x 4 used for most interior and exterior walls in a mild climate, which average R-value is approximately 2.5 per inch or normal weight concrete average R-value of approximately 0.1 per inch.
But, what is the good of insulating a wall, roof, and floor, if you still have thermal leaks through badly insulated windows and doors not to mention the exchange of heat that can be left unknowingly through these same doors and windows frame with a large gap between the frame and the container wall, and something also largely neglected, the thermal bridge. You must be sure that you install a thermal breaker to interrupt the exchange of temperature, they are also known as cold bridges or heat bridges.
In an airtight and insulated home, thermal bridges can account for heat loss of up to 30 percent, and they should be avoided whenever possible.
Let’s explain what exactly is a thermal bridge
In order to escape, the heat follows the path of least resistance and the thermal bridging is one of them, it generally occur when there is a break in/out, or penetration of the building’s insulation. Thermal bridges can be caused by:The junctions between the wall and door frame.The junctions between the wall and window frame.
- Holes in the building envelope for cables and pipes.
- Any inside metal touching the exterior wall (nails, screws, weld).
There are different kinds of Thermal Bridges
Repeating Thermal Bridges
Repeating thermal bridges follow a pattern and are “repeated” over an entire area of the building’s thermal envelope. Examples include steel wall ties
Repeating thermal bridges are both common and predictable, but can still cause a significant amount of heat loss.
Non-Repeating Thermal Bridges
Non-repeating thermal bridges are the opposite. These thermal bridges occur periodically and are found where there’s a break in the continuity of the building’s thermal envelope. Non-repeating thermal bridges can also occur when materials with a different thermal conductivity meet to form part of the envelope. Typical non-repeating thermal bridges include reveals around windows and doors, loft hatches and around other openings in the building’s thermal envelope.
Geometrical Thermal Bridges
As it says in the name, geometrical thermal bridges are indeed caused by the geometry of the building. Examples include the corners of external walls, the wall to floor and wall to roof junction and the junctions between adjacent walls. Geometrical thermal bridges occur more frequently with complex building forms, so it’s best to keep the overall design as simplistic as possible to reduce their occurrence.
Airtight and super-insulated homes are most susceptible to the effects of thermal bridging, so these must be taken into account to avoid unnecessary heat loss.
Always, taking into account the insulation, you have several ways of installing your windows and doors.
One option is welding it, and another is with a wood frame,
Any of these two methods will depend on what you prefer and what you are best at, but whatever method you choose, be conscious not to live a gap between the frame and the container wall where the exchange of temperature might take place.
All R-values shown in this page are approximately, and solely for information purpouses, they were calculated per inch of material, no density was specified, , for more accuracy we reccomend you to consult with your seller before buying.
In the context of building and construction,
It is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat.
Is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions.
Is the building industry term for thermal resistance “per unit area.
It is sometimes denoted RSI-value if the SI (metric) units are used.
An R-value can be given for material (e.g. for polyethylene foam), or for an assembly of materials (e.g. a wall or a window).
In the case of materials, it is often expressed in terms of R-value per unit length (e.g. per inch or meter of thickness).
R-values are additive for layers of materials.
The higher the R-value the better the performance”.
“The U-value or U-Factor
It is the overall heat transfer coefficient that describes how well a building element conducts heat or the rate of transfer of heat (in watts) through one square meter of a structure divided by the difference in temperature across the structure.
The elements are commonly assemblies of many layers of components such as those that makeup walls/floors/roofs etc.
It measures the rate of heat transfer through a building element over a given area under standardized conditions.
The usual standard is at a temperature difference of 24 °C (43 °F), at 50% humidity with no wind (a smaller U-factor is better at reducing heat transfer). It is expressed in watts per meter squared Kelvin (W/m2⋅K).
This means that the higher the U-value the worse the thermal performance of the building envelope.
A low U-value usually indicates high levels of insulation.
They are useful as it is a way of predicting the composite behavior of an entire building element rather than relying on the properties of individual materials.”
UNDERSTANDING R-VALUE AND U-VALUE AND WHY ARE THEY SO IMPORTANT
“Understanding R–value and U–value. resistance to heat flow which means that the higher the product’s R–value, the better it is at insulating the home and improving energy efficiency. Adversely, U–value measures the rate of heat transfer. This means that products with lower U–value will be more energy efficient”.
As Norbord North America explains in its blog
“Knowing what R-value and U-values mean is key to following energy codes and to selecting products that best suit the climate zone you are building in. R-value is essentially a product’s resistance to heat flow which means that the higher the product’s R-value, the better it is at insulating the home and improving energy efficiency. Adversely, U-value measures the rate of heat transfer. This means that products with lower U-value will be more energy efficient. It is tempting to think that these two values are direct opposites of each other, but there are some important differences to note. ““There is a tendency for people to confuse R and U-values with each other and their relationship with performance of materials. R and U-values are the P’s and Q’s of the thermal comfort vocabulary. Knowing the differences between them will enable you to make effective decisions when it comes to selecting the best building products to suit your needs.” Jiri Skopek from GreenGlobes“.
What material has the highest R value?
Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch.
Aerogel has the next highest R-value (about R-10 to R-30 per inch).
polyurethane (PUR) and phenolic foam insulations with R-7 per inch.
What material has the lowest R value?
Cellulose: Loose-fill cellulose is rated between R-3.2 and R-3.9 per inch, making it one of the least efficient insulation materials available
What is R-value?
“R-value tells us how well a particular construction material insulates. The higher the R-value, the better the insulation and the more energy you will save. An R-value only applies to specific materials, not to systems”.
R is the absolute thermal resistance (K⋅W−1)
Absolute thermal resistance, , quantifies the temperature difference per unit of heat flow rate needed to sustain one unit of heat flow rate. Confusion sometimes arises because some publications use the term thermal resistance for the temperature difference per unit of heat flux, but other publications use the term thermal resistance for the temperature difference per unit of heat flow rate.
Further confusion arises because some publications use the character R to denote the temperature difference per unit of heat flux, but other publications use the character R to denote the temperature difference per unit of heat flow rate. This article uses the term absolute thermal resistance for the temperature difference per unit of heat flow rate and uses the term R-value for the temperature difference per unit of heat flux.
In any event, the greater the R-value, the greater the resistance, and so the better the thermal insulating properties of the barrier. R-values are used in describing the effectiveness of insulating material and in the analysis of heat flow across assemblies (such as walls, roofs, and windows) under steady-state conditions. Heat flow through a barrier is driven by the temperature difference between two sides of the barrier, and the R-value quantifies how effectively the object resists this drive: The temperature difference divided by the R-value and then multiplied by the exposed surface area of the barrier gives the total rate of heat flow through the barrier, as measured in watts or in BTUs per hour.
What is U-value?
“U-value is generally used to rate door or window units. The lower the U-Value, the more energy-efficient the system in question will be. A U-value is typically a low number because it is a rating of how much heat energy is lost or gained.
If we look at the two values mathematically, U-value is the reciprocal of R-value; that is, U = 1/R and R = 1/U. For example, a material with an R-Value of 5 has a U-value of 0.2 (1 divided by 5). A high R-value means a low U-value but the real differences between them are far more complex.
U-value is more of an engineering term that describes thermal performance. It has traditionally been applied to materials such as window systems which are made up of a number of different materials. R-value is usually used in reference to construction components that are made up of only one material. When determining the R-value of a wall cavity (the area between framing members), you can add the individual R-values such as the wall sheathing, the insulation, and the internal drywall to get the overall R-value.
This is different with U-values because you can’t just add up the individual U-values of each component. Let’s take a window system for example. Each window is comprised of a number of different materials, some with disparate functions. While some may work to prevent heat transfer, others may be focused on air filtration or ventilation.
U-values represent the transfer of energy through conduction and radiation while R-value only represents resistance to heat transfer”.
Understanding how Insulation Works
“To understand how insulation works it helps to understand heat flow, which involves three basic mechanisms — conduction, convection, and radiation.
Conduction is the way heat moves through materials, such as when a spoon placed in a hot cup of coffee conducts heat through its handle to your hand.
Convection is the way heat circulates through liquids and gases, and is why lighter, warmer air rises, and cooler, denser air sinks in your home.
Thermal Radiation, also known as heat, is the emission of electromagnetic waves from all matter that has a temperature.
That heat travels in a straight line and heats anything solid in its path that absorbs its energy.
All matter with a temperature greater than absolute zero emits thermal radiation. Particle motion results in charge-acceleration or dipole oscillation which produces electromagnetic radiation.
When insulating your home, you can choose from many types of insulation. To choose the best type of insulation, you should first determine the following
- Where you want or need to install/add insulation
- The recommended R-values for areas you want to insulate.
The maximum thermal performance or R-value of insulation is very dependent on proper installation. To evaluate blanket installation, you can measure batt thickness and check for gaps between batts as well as between batts and framing. In addition, inspect insulation for a tight fit around building components that penetrate the insulation, such as electrical boxes. To evaluate sprayed of insulation, measure the depth of the insulation and check for gaps in coverage.
Blanket: batts and rolls
Blanket insulation — the most common and widely available type of insulation — comes in the form of batts or rolls. It consists of flexible fibers, most commonly fiberglass. You also can find batts and rolls made from mineral (rock and slag) wool, plastic fibers, and natural fibers, such as cotton and sheep’s wool
- Mineral (rock or slag) wool
- Plastic fibers
- Natural fibers
R-value: R 1.9 to R 2.5.
Depending on the density of the blocks, an 8-inch thick block wall without any other type of insulation.
Foamboard, to be placed on outside of the wall (usually new construction) or inside of the wall (existing homes)
Some manufacturers incorporate foam beads or air into the concrete mix to increase R-values
Concrete blocks are used to build home foundations and walls, and there are several ways to insulate them. If the cores aren’t filled with steel and concrete for structural reasons, they can be filled with insulation, which raises the average wall R-value. Field studies and computer simulations have shown, however, that core filling of any type offers little fuel savings because heat is readily conducted through the solid parts of the walls such as block webs and mortar joints.
It is more effective to install insulation over the surface of the blocks either on the exterior or interior of the foundation walls. Placing insulation on the exterior has the added advantage of containing the thermal mass of the blocks within the conditioned space, which can moderate indoor temperatures.
Foam board or rigid foam
R-value: R 6.5 to R 6.8
“Foam boards — rigid panels of insulation — can be used to insulate almost any part of your home, from the roof down to the foundation. They are very effective in exterior wall sheathing, interior sheathing for basement walls, and special applications such as attic hatches. They provide good thermal resistance (up to 2 times greater than most other insulating materials of the same thickness), and reduce heat conduction through structural elements, like wood and steel studs.”
Most Common materials
Insulating concrete forms (ICFs)
R-value: R 0.08
“Has virtually no insulating value
“Foam boards or foam blocks
Insulating concrete forms (ICFs) are basically forms for poured concrete walls, which remain as part of the wall assembly. This system creates walls with high thermal resistance, typically about R-20. Even though ICF homes are constructed using concrete, they look like traditional stick-built homes.
ICF systems consist of interconnected foam boards or interlocking, hollow-core foam insulation blocks. Foam boards are fastened together using plastic ties. Along with the foam boards, steel rods (rebar) can be added for reinforcement before the concrete is poured. When using foam blocks, steel rods are often used inside the hollow cores to strengthen the walls.”
R-value: R 3.5
“Loose-fill insulation consists of small particles of fiber, foam, or other materials. These small particles form an insulation material that can conform to any space without disturbing structures or finishes. This ability to conform makes loose-fill insulation well suited for retrofits and locations where it would be difficult to install other types of insulation.”
Most Common materials
Mineral (rock or slag) wool
Foil-faced kraft paper
Mineral (rock or slag)
Foam board or liquid foam insulation
Core straw core insulation
R-value: R 3.2 to R 3.9
“Fiberglass is cheap but requires careful handling.
It consists of extremely fine glass fibers–is one of the most ubiquitous insulation materials. It’s commonly used in two different types of insulation: blanket (batts and rolls) and loose-fill and are also available as rigid boards and duct insulation.
Manufacturers now produce medium- and high-density fiberglass batt insulation products that have slightly higher R-values than the standard batts. The denser products are intended for insulating areas with limited cavity space, such as cathedral ceilings.
High-density fiberglass batts for a 2 by 4 inch (51 by 102 millimeter [mm]) stud-framed wall has an R-15 value, compared to R-11 for “low density” types. A medium-density batt offers R-13 for the same space. High-density batts for a 2 by 6 inch (51 by 152 mm) frame wall offer R-21, and high-density batts for an 8.5-inch (216-mm) spaces yield about an R-30 value. R-38 batts for 12-inch (304-mm) spaces are also available.
Fiberglass loose-fill insulation is made from molten glass that is spun or blown into fibers. Most manufacturers use 40% to 60% recycled glass content. Loose-fill insulation must be applied using an insulation-blowing machine in either open-blow applications (such as attic spaces) or closed-cavity applications (such as those found inside existing walls or covered attic floors). Learn more about where to insulate.
One variation of fiberglass loose-fill insulation is the Blow-In-Blanket System® (BIBS). BIBS is blown in dry, and tests have shown that walls insulated with a BIBS system are significantly better filled than those insulated using other forms of fiberglass insulation such as batts.
The newer BIBS HP is an economical hybrid system that combines BIBS with spray polyurethane foam.
Mineral Wool Insulation Materials
R-value: R 3.7 to R 4.2
“The term “mineral wool” typically refers to two types of insulation material: 1-Rock wool, a man-made material consisting of natural minerals like basalt or diabase.
2-Slag wool, a man-made material from blast furnace slag (the waste matter that forms on the surface of molten metal).
Mineral wool is effective, but not fire-resistant.
Mineral wool contains an average of 75% post-industrial recycled content.
It doesn’t require additional chemicals to make it fire resistant, and it is commonly available as blankets (batts and rolls) and loose-fill insulation.”
Cellulose Insulation Material
R-value: R 3.2 to R 3.9
“Loose-fill cellulose is one of the least efficient insulation materials available.
Cellulose is fire-resistant, eco-friendly, and effective, but hard to apply.
Cellulose insulation is made from recycled paper products, primarily newsprint, and has a very high recycled material content, generally 82% to 85%. The paper is first reduced to small pieces and then fiberized, creating a product that packs tightly into building cavities and inhibits airflow.
Manufacturers add the mineral borate, sometimes blended with the less costly ammonium sulfate, to ensure fire and insect resistance. Cellulose insulation typically requires no moisture barrier and, when installed at proper densities, cannot settle in a building cavity.
Cellulose insulation is used in both new and existing homes, as loose-fill in open attic installations and dense packed in building cavities such as walls and cathedral ceilings. In existing structures, installers remove a strip of exterior siding, usually about waist high; drill a row of three-inch holes, one into each stud bay, through the wall sheathing; insert a special filler tube to the top of the wall cavity; and blow the insulation into the building cavity, typically to a density of 3.5 lb. per cubic foot. When the installation is complete, the holes are sealed with a plug and the siding is replaced and touched up if necessary to match the wall.
In new construction, cellulose can be either damp-sprayed or installed dry behind netting. When damp sprayed, a small amount of moisture is added at the spray nozzle tip, activating natural starches in the product and causing it to adhere inside the cavity. Damp-sprayed cellulose is typically ready for wall covering within 24 hours of installation. Cellulose can also be blown dry into netting stapled over building cavities.”
Natural Fiber Insulation Materials
R-value: R 1.4 to 2.0
“Some natural fibers–including cotton, sheep’s wool, straw, and hemp–are used as insulation materials.”
2R-value: R 3.2 to R 3.7
“Cotton insulation consists of 85% recycled cotton and 15% plastic fibers that have been treated with borate–the same flame retardant and insect/rodent repellent used in cellulose insulation. One product uses recycled blue jean manufacturing trim waste. As a result of its recycled content, this product uses minimal energy to manufacture. Cotton insulation is available in batts and costs about 15% to 20% more than fiberglass batt insulation.”
R-value: R 3.5 to R 3.8
“For use as insulation, sheep’s wool is also treated with borate to resist pests, fire, and mold. It can hold large quantities of water, which is an advantage for use in some walls, but repeated wetting and drying can leach out the borate. Sheep’s wool batts for a 2 by 4 inch and 2 by 6 inch stud-framed wall offer an R-13 and R-19 value, respectively.”
R-value: R 0.94 to 2.38
“Straw bale construction, popular 150 years ago on the Great Plains of the United States, has received renewed interest.
The process of fusing straw into boards without adhesives was developed in the 1930s. Panels are usually 2 to 4 inches (5 to 102 mm) thick and faced with heavyweight kraft paper on each side. The boards also make effective sound-absorbing panels for interior partitions. Some manufacturers have developed structural insulated panels from multiple-layered, compressed-straw panels.”
R-value: R 3.5
“Hemp insulation is relatively unknown and not commonly used in the United States. Its R-value is similar to other fibrous insulation types.”
Polystyrene Insulation Materials
R-value: R 3.85 To R 4.0
“Polystyrene–a colorless, transparent thermoplastic–is commonly used to make foam board or beadboard insulation, concrete block insulation, and a type of loose-fill insulation consisting of small beads of polystyrene.
Molded expanded polystyrene (MEPS), commonly used for foam board insulation, is also available as small foam beads. These beads can be used as a pouring insulation for concrete blocks or other hollow wall cavities, but they are extremely lightweight, take a static electric charge very easily, and are notoriously difficult to control.
Other polystyrene insulation materials similar to MEPS are expanded polystyrene (EPS) and extruded polystyrene (XPS). EPS and XPS are both made from polystyrene, but EPS is composed of small plastic beads that are fused together and XPS begins as a molten material that is pressed out of a form into sheets. XPS is most commonly used as a foam board insulation. EPS is commonly produced in blocks. Both MEPS and XPS are often used as insulation for structural insulating panels (SIPs) and insulating concrete forms (ICFs). Over time, the R-value of XPS insulation can drop as some of the low-conductivity gas escapes and air replaces it–a phenomenon is known as thermal drift or aging.
The thermal resistance or R-value of the polystyrene foam board depends on its density. Polystyrene loose-fill or bead insulation typically has a lower R-value compared to the foam board.”
Polyisocyanurate Insulation Materials
R-value: R 5.6
“Polyisocyanurate or polyiso is a thermosetting type of plastic, closed-cell foam that contains a low-conductivity, hydrochlorofluorocarbon-free gas in its cells.
Polyisocyanurate insulation is available as a liquid, sprayed foam, and rigid foam board. It can also be made into laminated insulation panels with a variety of facings. Foamed-in-place applications of polyisocyanurate insulation are usually cheaper than installing foam boards and perform better because of the liquid foam molds itself to all of the surfaces.
Over time, the R-value of polyisocyanurate insulation can drop as some of the low-conductivity gas escapes and air replaces it — a phenomenon is known as thermal drift or aging. Experimental data indicates that most thermal drift occurs within the first two years after the insulation material is manufactured.
Foil and plastic facings on rigid polyisocyanurate foam panels can help stabilize the R-value. Testing suggests that the stabilized R-value of rigid foam with metal foil facings remains unchanged after 10 years. Reflective foil, if installed correctly and facing an open-air space, can also act as a radiant barrier. Depending upon the size and orientation of the air space, this can add another R-2 to the overall thermal resistance.
Some manufacturers use polyisocyanurate as the insulating material in structural insulated panels (SIPs). Foam board or liquid foam can be used to manufacture a SIP. Liquid foam can be injected between two wood skins under considerable pressure, and, when hardened, the foam produces a strong bond between the foam and the skins. Wall panels made of polyisocyanurate are typically 3.5 inches (89 mm) thick. Ceiling panels are up to 7.5 inches (190 mm) thick. These panels, although more expensive, are more fire and water vapor-diffusion resistant than EPS. They also insulate 30% to 40% better for a given thickness.”
Polyurethane Insulation Materials
R-value: R 3.4 to R 6.7
“Polyurethane is a foam insulation material that contains a low-conductivity gas in its cells. Polyurethane foam insulation is available in closed-cell and open-cell formulas. With closed-cell foam, the high-density cells are closed and filled with a gas that helps the foam expand to fill the spaces around it. Open-cell foam cells are not as dense and are filled with air, which gives the insulation a spongy texture and a lower R-value.
Like polyiso foam, the R-value of closed-cell polyurethane insulation can drop over time as some of the low-conductivity gas escapes and air replaces it in a phenomenon known as thermal drift or aging. Most thermal drift occurs within the first two years after the insulation material is manufactured, after which the R-value remains unchanged unless the foam is damaged.
Foil and plastic facings on rigid polyurethane foam panels can help stabilize the R-value, slowing down thermal drift. Reflective foil, if installed correctly and facing an open-air space, can also act as a radiant barrier. Depending upon the size and orientation of the air space, this can add another R-2 to the overall thermal resistance.
Polyurethane insulation is available as a liquid sprayed foam and rigid foam board. It can also be made into laminated insulation panels with a variety of facings.
Sprayed or foamed-in-place applications of polyurethane insulation are usually cheaper than installing foam boards, and these applications usually perform better because of the liquid foam molds itself to all of the surfaces. All closed-cell polyurethane foam insulation made today is produced with a non-HCFC (hydrochlorofluorocarbon) gas as the foaming agent.
Low-density, open-cell polyurethane foams use air as the blowing agent and have an R-value that doesn’t change over time. These foams are similar to conventional polyurethane foams but are more flexible. Some low-density varieties use carbon dioxide (CO2) as the foaming agent.
Low-density foams are sprayed into open wall cavities and rapidly expand to seal and fill the cavity. Slow expanding foam is also available, which is intended for cavities in existing homes. The liquid foam expands very slowly, reducing the chance of damaging the wall from overexpansion. The foam is water vapor permeable, remains flexible, and is resistant to wicking of moisture. It provides good air sealing and is fire resistant and won’t sustain a flame.
Soy-based, polyurethane liquid spray-foam products are also available. These products can be applied with the same equipment used for petroleum-based polyurethane foam products.
Some manufacturers use polyurethane as the insulating material in structural insulated panels (SIPs). Foam board or liquid foam can be used to manufacture a SIP. Liquid foam can be injected between two wood skins under considerable pressure, and, when hardened, the foam produces a strong bond between the foam and the skins. Wall panels made of polyurethane are typically 3.5 inches (89 mm) thick. Ceiling panels are up to 7.5 inches (190 mm) thick. These panels, although more expensive, are more fire and water vapor-diffusion resistant than EPS. They also insulate 30% to 40% better for a given thickness.”
Vermiculite and Perlite Insulation Materials
R-value: R 2.0 to R 2.7
“Vermiculite and perlite insulation materials are commonly found as attic insulation in homes built before 1950. Vermiculite insulation materials aren’t widely used today because they sometimes contain asbestos. However, according to the U.S. Environmental Protection Agency, asbestos is not intrinsic to vermiculite. Only a few sources of vermiculite have been found to contain more than tiny trace amounts. Still, if you have vermiculite insulation in your attic, do not disturb it. If you want to add insulation to your attic, use an insulation contractor who is trained and certified in handling asbestos.
Vermiculite and perlite consist of very small, lightweight pellets, which are made by heating rock pellets until they pop. This creates a type of loose-fill insulation made of pellets that can be poured into place or mixed with cement to create a lightweight, less heat-conductive concrete.”
Urea-Formaldehyde Foam Insulation Materials
R-value: R 5.0
“Urea-formaldehyde (UF) foam was used in homes during the 1970s and early 1980s. However, after many health-related court cases due to improper installations, UF foam is no longer available for residential use and has been discredited for its formaldehyde emissions and shrinkage. It is now used primarily for masonry walls in commercial and industrial buildings.
UF foam insulation uses compressed air as the foaming agent. Nitrogen-based UF foam may take several weeks to cure completely. Unlike polyurethane insulation, UF foam doesn’t expand as it cures. Water vapor can easily pass through it, and it breaks down at prolonged temperatures above 190°F (88°C). UF foam contains no fire retardant.”
Cementitious Foam Insulation Material
R-value: R 3.9
“The cementitious insulation material is a cement-based foam used as sprayed-foam or foamed-in-placed insulation. One type of cementitious spray foam insulation known as air krete® contains magnesium silicate and has an initial consistency similar to shaving cream. Air krete® is pumped into closed cavities. Cementitious foam costs about as much as polyurethane foam are nontoxic and nonflammable and are made from minerals (like magnesium oxide) extracted from seawater.”
Phenolic Foam Insulation Material
R-value: R 6.7 to R 7.5
“Phenolic (phenol-formaldehyde) foam was somewhat popular years ago as rigid foam board insulation. It is currently available only as a foamed-in-place insulation.”
“Facings are fastened to insulation materials during the manufacturing process. A facing protects the insulation’s surface, holds the insulation together, and facilitates fastening to building components. Some types of facing can also act as an air barrier, radiant barrier, and/or vapor barrier and some even provide flame resistance.
Common facing materials include kraft paper, white vinyl sheeting, and aluminum foil. All of these materials act as an air barrier and a vapor barrier. Aluminum foil can also act as a radiant barrier. Your climate and where and how you’re installing the insulation in your home will determine what type of facing and/or barrier, if any, you’ll need.
Some of the same materials used as insulation facings can be installed separately to provide an air barrier, vapor barrier, and/or radiant barrier.”