How to Insulate a Loft

Written by billy mccarley
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An uninsulated loft can be scorching during the summer and icy during the winter. This would be OK if you never used the loft for living space; however, once the loft space becomes a dwelling place, you will need to insulate it in order to prevent hot and cold exchanges between the inside and out. There are several choices of insulation available for the do-it-yourself homeowner--some more difficult than others. Regardless of your choices, you can expect to insulate your loft in one day or less.

Skill level:

Things you need

  • Insulation-fibreglass and cellulose (blown)
  • Eye Goggles
  • Dust Mask
  • Stapler
  • Razor Knife

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  1. 1

    Remove any loose materials, such as old insulation or dust, from the loft ceiling and floors. Vacuum any excess dust and dirt from the cavities between the ceiling and floor framing.

  2. 2

    Install cellulose insulation into the floor of the loft. Cellulose insulation, also called blown insulation, consists of recycled newspapers. It is distributed by an electric blower that resembles a large vacuum with a feed bin on top. It has a 200 feet hose and an electric or gas engine that blows the insulation through the hose and into the area being insulated. Have a helper feed the insulation--it comes in square plastic bales--into the bin while you operate the hose. You will need to blow the insulation between the floor framing of the loft. You may pile it up to the top of the framing members but don't go over.

  3. 3

    Install fibreglass batt insulation into the ceiling of the loft. If you choose fibreglass batt insulation, you will purchase the insulation in rolls that are 24 inches wide--the width of the ceiling framing spacing--and 8 feet long. Choose an R-value(insulation thickness) that is thick enough for the framing; Ceiling framing will be 2-by-6 or 2-by-8 framing, so you would use R-19 for 2-by-6 and R-25 for 2-by-8 framing.

    The rolls will have several 8 feet pieces that are all rolled, end-to -end, into one roll. Unroll the insulation and lay it onto a solid surface for cutting--you may or may not need to cut the insulation; it will depend on the length of the area being insulated. With the face of the insulation down (paper up), depress the insulation with a 2-by-4 and cut the insulation with a razor knife.

  4. 4

    Insert the fibreglass insulation into the cavity between the ceiling framing fibreglass side first, and staple the paper flanges, attached to the paper face of the insulation, to the framing. Continue to insert the insulation until the entire ceiling has been insulated.

  5. 5

    Insulate any hard to reach areas with spray foam insulation. You may purchase the foam by the can or by the kit. The kit will allow you to insulate larger areas, while the can will allow you to insulate smaller areas, such as holes and gaps less than 6 inches. The spray foam insulation will expand, so you will only need to spray a 1 to 2 inch thick coat into any cavity.

Tips and warnings

  • Always wear a dust mask and goggles

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