Generally, fiberglass insulation is 3 ½ inches thick, which make it too dense to layer in conventional walls without compressing the insulation. Compressing the insulation to make it fit is not recommended because the material loses its insulating value. To gain the advantages of fiberglass insulation, you must install the insulation in the proper manner. There are two other combinations you may want to consider if your primary objective is to get a higher R-value for the wall units.
Installation Tips
Fiberglass roll insulation is also called batt or blanket insulation. Fiberglass is made from mineral fibers, like rock wool or fiberglass, and is available in a variety of thicknesses. Measure the ability of fiberglass batt insulation to prevent heat loss by comparing the R-value per inch of insulation. Depending on the product, fiberglass roll insulation can have an R-value of 3.1 to 3.8 per inch of insulation.
Contact the local building department to find out the R-value recommendation in your climate. Also, find out what the rules are for vapor barriers. If vapor barriers are required, the facing of the fiberglass insulation must be installed to the conditioned side. You may use six-millimeter polyethylene if you are using un-faced insulation and a vapor barrier is required.
If you want to increase the overall insulating value of wall assemblies, you can place rigid foam board on the exterior sheathing before installing the siding. Another option is to consider having a one-inch layer of closed-cell spray foam insulating product installed first, and then layer it with 3½ inches of un-faced fiberglass.
The recommend R-value for new homes exterior walls is R-19. The insulating value is usually reached through a combination of insulating the cavities and sheathing on the exterior of the wall. The type of framing determines how much fiberglass insulation you can install in a wall cavity. A wall constructed of 2 x 4 studs can only hold 3 ½ inches of fiberglass insulation, which is R-13 or R-15 fiberglass blanket insulation. A wall made of 2 x 6 studs can hold 5 ½ inches or up to R-21 fiberglass batt insulation.
Before proceeding with your insulation project, inspect the walls for evidence of water stains and moisture infiltration. Any cracks or openings must be sealed. Fiberglass insulation cannot function as an air barrier or vapor barrier. If the insulation gets wet, it loses its R-value because it leaves un-insulated spots in the cavity. One of the best products for sealing cracks and holes is spray foam.
Related posts
Patch up holes in plaster walls with fiberglass mesh tape.Cracking or crumbling plaster walls are a nuisance to the structure and beauty of a wall. Though it may be tempting to replace damaged pla...
Home InsulationBy keeping your heat in your home longer, home insulation can keep your energy bills from getting too high. This type of insulation comes in fiberglass, foam and cellulose. It is pl...
Seal around electrical outlets to prevent moist air from leaking in.Basement walls and floors have special problems when it comes to insulation, according to the Minnesota Department of Commerce E...
Older homes were often built with hollow exterior walls at a time when heat was cheap. Fortunately, you do not have to rip out the wallboard to properly insulate those hollow walls. You can rent a...
Soundproof walls have a multitude of uses in homes and businesses. However, not all soundproof walls are identical because different construction methods and materials absorb various sound frequen...
