According to the latest industry trends, fiberglass looks to have been toppled from its throne as the king of cost-effective insulation.
Savvy buyers are choosing a variety of different insulation systems over fiberglass for many reasons. Vapor barriers, mold problems and the elimination of ventilation are three main components in the decision to switch. Others are swayed by heating and cooling cost savings. And of course, certain of people are intrigued about these new systems just because they’re something new.
Here are the competing newcomers, in descending order:
Cold Climate System: This insulation system has existed in cold climates such as Canada and Scandinavia for years. The most important consideration with a cold climate insulation system is that there needs to be a thermal break (such as insulation board) on the exterior of the building, followed by an airspace between the thermal break and the exterior siding or roofing.
The cold climate insulation system can be augmented further by using advanced framing. The key concept with advanced framing is to use fewer framing members to construct the exterior walls and avoid double framing members as much as possible. Framing members are the weak link in virtually all insulation systems. They provide a thermal transfer, and an easy way for heat to escape.
Spray foam and advanced framing with insulation board installed beneath the siding will give you an extremely high R-value/Insulation value. This system could bring you the most value for your dollar, especially as many custom homes are more complicated to build than traditional designs. A more complicated design is more expensive to insulate with an SIP system.
No lead time is required, changes and remodeling are done using conventional methods, and there are no special accommodations needed for the plumbing and electrical work. Another advantage with this system is that any remodels, repairs or rot issues that may come up can be dealt with in a simple, straightforward fashion.
SIPs (Structural Insulated Panels): These are factory produced panels using foam and OSB plywood. Think of a giant Oreo cookie. These two-sided foam panels with OSB plywood get their strength from the bond between the foam and the two plywood layers. They function just like a very broad I-beam!
The easiest place to use these panels is installment over a timber frame roof system; provided the roof is not too complex. Unlike walls, which have many window and door cutouts, the roof will typically have only a few openings. Windows and doors ore often subject to last-minute revisions or job site changes. It is also very convenient to simply install SIPs over the timber frame instead of installing roof framing members.
SIPs also enjoy the benefit of reduced construction time and an extreme reduction in framing members. Just remember to place your order well in advance, because lead time can be somewhat substantial.
Open and Closed Cell Spray Foam: The sealing properties of foam are promoted as having the ability to eliminate mold and be superior in a whole-house insulation. Open and Closed-cell spray foam vary in cost and effectiveness:
Closed-cell spray foam performs better in sealing cracks or making a space airtight. Some people have chosen to use a combination of cellulite or cotton with a thin layer of the closed cell foam. This combination gives you the airtight benefit of closed cell foam without the cost of filling the whole wall or roof cavity. Another benefit is the added strength gained when filling the stud spaces with foam. Closed-cell spray foam has been put through stress tests to ensure quality.
Open-cell foam is less expensive and does a great job of insulating when the whole wall or roof cavity is filled. And because foam allows no air movement, it eliminates the need for ventilation.
Cellulite and Cotton: Cellulite or cotton is applied with a spray apparatus similar to spray foam. The shredded cotton or cellulite is mixed with glues to adhere to the walls and avoid settling. Cellulite and cotton are a better choice than fiberglass because they dry easily if they get wet and will naturally breakdown if thrown away in a landfill. Another advantage these have over foam is the lack of petroleum ingredients, while still containing glues and fire retardants.
Straw Bale System: I think of the straw bale house as a neat, whimsical solution, provided it is built in the right environment or climate. The stucco and deep window wells go well with an exposed timber frame.
Flash and Batt System: In my opinion, the Flash and Batt system is the best situation to use fiberglass insulation. This system uses a thin layer of closed-cell foam to keep the exterior envelope airtight and then the fiberglass insulation provides the R-value. This addresses the Achilles’ heel of fiberglass insulation, which is its’ inability to move air. If your exterior walls are not sealed properly (allowing air movement) – then you will not get good R-value from your fiberglass insulation.
I want you to be aware of the many other insulation options available to you that may not be mainstream. Are you the type of person who does a bit of research before buying? There are many other non-mainstream insulation options available to you and some of these alternate systems could potentially fit your situation to a tee.
In light of growing awareness of energy conservation and problems associated with poor insulation systems, we strongly encourage you to research your options before choosing any type of insulation. As you are moving forward with the mindset of a timber enthusiast, you are certainly someone who will want to make an informed choice.
P.S. Below is a link to David South’s article on our website, giving a thorough explanation of insulation values and trends. David B. South is President and founder of Monolithic, Inc., headquartered in Italy, Texas. His article explains the major flaw in the R-value ratings system. It is a bit technical, but you will get a sound understanding of all the factors which will influence how well your insulation system performs.