How to Install Insulation: Wall Insulation
Installing insulation is not a difficult task to complete. However, it is a very important component of a building and a proper insulation installation will produce a comfortable building and can reduce energy costs. The main purpose of the insulation is to provide thermal comfort for its occupants. The type and amount of insulation depends on the building design, climate, energy costs and budget. Building codes will guide you to determine the minimum amount of insulation that you must install to provide comfort to its occupants.
How to Install Insulation: Faced Batt and Unfaced Batt
Batt insulation is available with and without facing. Faced batts are used in exterior walls as well as attics, finished basements, ceilings, floors, knee walls and cathedral ceilings. A faced batt is an insulation material that contains a facing material usually serving as a vapor retarder. Normally faced batt insulation is easier to handle and to install, and even some manufacturers have pre-cut pieces of faced batt insulation. Factory-applied vapor retarder facings are generally made of kraft paper.
Faced batts are attached to framing members by stapling through the flanges. Unfaced batts are installed between framing members but not attached, allowing friction to hold them in place. It is a recommended practice and for better energy efficiency, your home should be properly insulated from the roof down to its foundation, including attic spaces, HVAC ducts, ceilings, walls, floors and foundations.
How to Install Insulation: Unfaced Batt Installation Tips
- Use the correct size of insulation to fit at the sides and ends.
- Fill the cavity completely but don't shove it in.
- Fluff the insulation material to its full expansion by pulling it forward to fill the depth of the cavity.
- No gaps should be allowed nor the insulation be compressed. Compression changes the R-value of the insulation.
- When installing insulation into non-standard openings, cavities should be filled by insulation at least 1: wider than the space to be filled.
- When installing it around wiring and pipes, cut slits in the batt so it fits around any pipes and electrical wires, one layer in front and one layer fitting behind the pipe.
- Narrow spaces, 2" or less, shall be filled with small pieces of insulation.
How to Install Insulation: Faced Batt Installation Tips
The facing material is generally a vapor retarder that helps resist the movement of moisture vapor to cold surfaces where it can condense.
- When installing faced batt insulation, the facing side should be installed toward living spaces.
- Staple the flanges of faced batts to the inside or face of the joists. It must be continuous with no penetrations.
- If building codes requires, overlap the flanges and staple them to the edges of the framing members.
- Tears or breaks on insulation material should be sealed with duct tape or other waterproof tape.
- Always cut on the unfaced side of the batt.
- If you're using faced batts, stable the lip of the flanges to the face of the wall stud every 8 to 12 inches from the top down or according to manufacturer’s specifications on facing
Wall Insulation General Tips
- All walls adjacent to tubs and showers must be fully insulated.
- The R-value should be marked visibly on the insulation, faced or unfaced.
- Insulation should be installed between the sheathing and the rear of electrical boxes. Batts should be cut to fit around electrical boxes with a piece placed behind each box.
- Rim joists should be insulated to the same R-value as the walls. Insulation shall be cut to fit into the rim joist.
- If the climate is too cold water pipes installed on outside walls, shall have at least two thirds of the insulation between the pipe and the outer wall.
- Insulation should be placed between the outside wall and the pipes. If kraft facing is used, it should be in direct contact with the gypsum board, if not possible assure that it is close enough to the gypsum board. Kraft facing should never be left exposed.
- A recommended insulation value of at least R-19 should be used on knee-walls and skylight shafts.
- Any insulation installed with water should be thoroughly dried before covering with gypsum board.
- Taping vapor retarder facings is not standard practice.
- All walls of interior closets for HVAC and/or water heating equipment should contain the same R-value as the exterior walls.
- All insulation requires proper air sealing or the installation of a rated air barrier.