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How to Install Fiberglass Attic Insulation

If small critters get into your attic they can cause damage to your insulation, wiring or framing. Here is the best way to repair insulation after heavy pest damage.

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  • Time

    Day

  • Price Range

    $100 - $250

  • Difficulty

    Easy to Moderate

Highlights:

Step 1: Read the Tips

  • Fiberglass insulation can be hazardous. Wear the proper safety equipment. Rubber gloves stop the fiberglass particles from sticking to your hand and can be washed off easily. Also, make sure you are wearing a fiberglass-rated mask. Other masks can allow tiny fiberglass particles to be inhaled into your lungs.

  • Rub your skin with baby powder; it will prevent the fine particles of insulation from entering your pores. Or duct tape your rubber gloves over a loose-fitting long sleeve shirt.

  • Lay wood slats across the joists so you can safely walk across the attic and not disturb the insulation.

  • There are various types of insulation, check your local building codes for the recommended R-value. The higher the R-value, the better insulator.

  • If you have recessed lighting, keep the insulation at least 3 inches away from the fixture to ensure there are no fire hazards.

  • Do not block any vents in the attic with insulation. It is important to keep a natural airflow above the insulation.

  • Step 2: Remove Damaged Section and Clean

    Insulation that has been ripped up and/or soiled by animal waste must be completely removed. If the damage is severe, hire a professional to ensure proper removal of hazardous waste. Proper safety equipment must be used, including goggles, gloves, and even a body suit. Once the insulation is removed, spray a 10:1 solution of water and bleach to the affected areas. Let dry completely.

    Step 3: Measure Attic Space

    Determine how much insulation you will need. Multiply the length and width of the space to get the total square footage. Check your local building codes for recommended R-value for your area.

    Step 4: Install Insulation

    There are many different ways to install insulation. The pros often use spray foam insulation or blow shredded insulation. If installing shredded insulation, fill the attic space at least 15 inches high with insulation.

    If installing fiberglass mats, start by laying the mats at the furthest point from the attic access. Roll the sheets out and cut them perpendicular. When you reach a wall, pull the insulation back over a joist, lay a level over the insulation and cut across the level. This will give you support to make a straight and even cut. Work your way across the attic until you are back at the attic access point. If you run into a cross brace cut a notch in the insulation and continue on.

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