Insulation is key to making today’s home more energy efficient but you’ve got to use the right product, in the right place. For example, DAP provides different foam products — you need to use the one for windows and doors because the other foam product will expand and harden, causing potential damage to your door or window.
Most insulation decisions are made when a house is built. Homeowners can make their homes more energy efficient insulation and sealing but you need to research product options and while it might make sense to handle small repairs yourself, you probably want to hire a professional for larger projects.
This article reviews the different types of insulation available today so you know what to look for when you’re building, remodeling or wanting to improve your home’s energy efficiency. See Insulation Provides Comfort and Lower Energy Costs, to learn more about when to add insulation.
Blanket insulation is the most common type of insulation. It comes in batts or rolls made fro
This insulation comes in widths ready to install between wall studs, attic trusses or rafters and floor joists, which are 16 or 24 inches apart. They’re available with or without facing and the location of the installed insulation will determine the thermal resistance (R-value) and facing needed.m fiberglass, mineral (rock and slag) wool, plastic fibers or natural fibers like cotton and sheep’s wood.
Where the space you want to insulate is difficult to access, loose-fill insulation is the best solution. These small particles can fit into any space without disturbing the structure, i.e. blown-in insulation is typically added to exterior walls from the outside when you’re replacing your siding. As shown above, with little space between the attic floor and ductwork, loose-fill insulation works well.
The most common materials used are cellulose, fiberglass and mineral (rock or slag) wool. All of these materials include some percentage of recycled waste materials — cellulose is made from recycled newsprint, fiberglass contains recycled glass and mineral wool is usually made from post-industrial recycled content. Less common loose-fill insulation materials include polystyrene beads, vermiculite and perlite.
Sometimes used to add insulation to a basement or garage, foam board insulation is gaining new interest as an added insulation barrier to the outside of a home. The benefit is these rigid boards will insulate the wall studs in addition to the cavities filled with other insulation. There are fewer seams so they also reduce the gaps where air can flow or moisture can penetrate the homes exterior.
The most common materials used to make foam boards include polystyrene, polyisocyanurate and polyurethane.
Concrete Block Insulation
When building a new house, your builder might use insulating concrete block walls where the block cores don’t need to be filled with rebar and concrete for structural reasons. There isn’t a lot of energy savings because heat still moves through the solid part of the concrete blocks and mortar joints. You’ll get more value from insulation installed on the outside or inside foundation walls … and you don’t want to confuse traditional concrete block foundations with the new insulating concrete forms (ICFs).
Insulating concrete forms (ICFs) are interlocking, hollow-core foam insulation blocks that are fastened together using plastic ties. Steel rods (rebar) are added for reinforcement and the core is filled with concrete. The forms remain in place, creating walls with thermal resistance of approximately R-20.
ICF costs are sensitive to labor and material costs versus traditional, stick built construction. They’re lower for basement construction due to several steps being combined into one step. Above grade, ICF construction is more expensive so overall ICF can add 3 to 5 percent to overall construction costs. You need an experienced contractor to install an ICF system (Insulating Concrete Form Association).
Reflective Insulation Systems Provide Radiant Barriers
Unlike other insulation systems that resist the flow of warm air, radiant barriers and reflective insulation reflects radiant heat away from a house. They’re usually installed in attics to reduce summer heat gain and lower cooling costs. Radiant barriers are more effective in hot climates where cooling air ducts are located in the attic like our photo illustrates (model home in Florida), enabling in some instances, the purchase of a smaller air conditioning system.
There are 2 basic types of spray foam insulation and lots of controversy around them, so while these newer products are becoming more popular, homeowners should thoroughly research your options, i.e. you don’t want products that use chlorofluorocarbons (CFCs) or hydrochlorofluorocarbons (HCFCs), which are harmful to the earth’s ozone layer.
- Open-cell foams are permeable to moisture and impermeable to air. Their R-value is about 3.6 per inches of foam. Where your home’s framing is deep enough to achieve the required R-value with open-cell foam, this solution may cost less than closed-cell foam which is almost twice the price.
- Closed-cell foams stop air and moisture, so in areas vulnerable to water infiltration (or flooding from a hurricane), this is the best solution. R-value is roughly 6.5 per inch, and with the density and glue-like holding power, closed-cell foam also adds structural strength to walls, the ceiling and roof.
Depending on which foam insulation material you use, it can be sprayed, foamed-in-place, injected, or poured. You’ll need to hire an experienced installer as most of these products (except those in spray paint like can for small jobs, i.e. around door locks and outlets) require special equipment and certification. After the insulation is installed, an approved thermal barrier equal in fire resistance to half-inch gypsum board must cover all foam materials.
Structural insulated panels (SIPs) are prefabricated panels for use as walls, ceilings, etc. Each panel is made of 4 to 8 inch thick foam board sandwiched between 2 sheets of oriented strand board (OSB). The insulation facing is glued to the foam core and the panels are either pressed or place in a vacuum to bond the sheathing (OSB) and foam core together.
SIPs provide more uniform insulation compared to tradition construction methods, offering energy savings estimated at 12 to 14%. According to the Structural Insulated Paneling Association and EPS Molders, the payback for SIPs construction ranges from 2.5 to 7.8 years in the US (for more information read Structural Insulated Panels Reduce Global Warming).
The manufacturing process used to create SIPs is critical to ensure they don’t delaminate. Panels must also be smooth (surfaces and edges) to insure that connect to other construction materials correctly. You or your builder should do sufficient research into quality control, testing and compare warranties to make sure you’re getting the product you want.
The OSB interior must be covered with a fire rated material like drywall and routine precautions for dealing with insects and rodents are recommended, i.e. applying insecticides, keeping indoor humidity levels Low (below 50%) and insuring ground water flows away from the house. More important is ventilation as a house built with SIPs is more airtight and will typically use a mechanical ventilation system to prevent moisture problems.