Properly insulating a home is critical to homeowner comfort. Poorly installed insulation can lead to cold spots, moisture problems and higher energy use resulting from an increase in heating or cooling. Uncomfortable homeowners are more likely to complain, incur warranty expenses, and tell their friends about their dissatisfaction, which can cause damage to the company reputation. In order to ensure the comfort of a home, you should know the best practices for installing insulation.
One such product used to insulate a home is fiberglass batts, which are primarily installed in wall cavities and in attics. When using fiberglass batts, it is always important that they be cut so that they fit tightly into any non-standard spaces. A snug fit is essential to installing fiberglass insulation effectively. However, fiberglass batts should not be compressed, since compression degrades the insulation value.
In exterior walls, the appropriate thickness of batt is needed for the specific wall; otherwise gaps will result between the batt and the drywall, compromising the thermal performance. Using best practices when installing fiberglass batts will ensure an excellent level of cost-effective thermal performance.
In hot-humid climates where moisture from outside the homes usually travels in, using unfaced batts in exterior walls is recommended to avoid moisture retention problems. In cold or mixed climates, on the other hand, moisture often moves from inside the home to the outside. The best practice for installing fiberglass batts in these climates is to use kraft-faced batts in order to keep moisture away from the exterior sheathing. Using the appropriate type of fiberglass batt will help prevent mold and decay problems.
Installing fiberglass batts is one way to provide high quality insulation for a home. The following tips will help you ensure that the proper insulation contributes to a comfortable living atmosphere and a durable home. Employing best practices when installing fiberglass batts will improve customer satisfaction, increase referrals, and enhance the company reputation.
INSTALLING FIBERGLASS BATT INSULATION
ALWAYS:
- Avoid gaps, tight turns, and compression.
1. Cut insulation to fit snugly in non-standard spaces.
2. Slit batts to fit around wiring and plumbing.
3. Notch out around electrical boxes and use scraps to fill in behind.
- Install long runs first, then use scraps to fill in smaller spaces and gaps.
- Use unfaced batts in hot and humid climates.
- Even if blown-in insulation is to be generally applied, use fiberglass batts to insulate areas that will be inaccessible to the blown-in insulation, such as behind bath enclosures.
WALLS:
- Friction fit the batts in place until covered by drywall or sheathing.
- Insulate before installing stairs and tubs and other features that will block access.
KNEE WALLS:
- Seal knee wall to create a continuous air barrier. Knee walls can be sealed following the wall itself and attic floor or along the sloping edge of the attic roof. Rigid foam insulation, taped at the seams with housewrap tape, can be used to seal the backside of the knee wall and the underside of the roof. Sealing along the roofline is preferred in new construction.
- Insulate and airseal the rafter space along the sloping ceiling of the knee wall attic space or insulate and air seal the roofline wall and floor.
- Rafters should receive R-19 or R-30 insulation.
- Cover rafters with a sealed air barrier, such as drywall or foil-faced hardboard.
- Caulk the barrier to the top plate of the wall below the attic space and to the top plate of the knee wall itself.
- Seal all other cracks and holes.
CEILINGS:
- Insulate and seal the attic access door.
- Install insulation over IC, AT rated recessed cans.
- Ventilation pathways?
- Install insulation baffles.
BAND JOISTS:
- Place insulation in the cavities between joists and subfloor.
- Caulk bottom plate to subfloor.
- Caulk band joist to subfloor and plates and insulate.
- Caulk bottom plate to subfloor.
UNDER FLOOR INSULATION:
- Metal stays, lathe or stainless steel wire support insulation in joist cavities.
- In new construction, it is preferred that crawlspace walls are insulated. If underfloor insulation is to be used, it can be held in place with metal staves, lathe, stainless steel wire or twine.
- If truss systems are used under floors, an approach better than batt insulation is to install netting or rigid insulation to the underside of the floor trusses and fill the joist cavity with blown-in insulation.
For more information visit:
Energy Efficient Building Association’s Builder’s Guide Hot-Humid Climates, 2000.
U.S. DOE Technology Fact Sheet on Attic Access.
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