How to DIY Install Ceiling Insulation in Your Home

Did you know that you can lose up to 35% of your internal heat through an uninsulated ceiling in winter? Your home can retain just as much heat on a hot day in summer, making your house feel like a sweatbox.

Insulation, once installed in your home, will go a long way to providing you with warmer winters and cooler summers and help you save money on your heating and cooling bills all year round.

What you need:

  • Retractable utility knife and a tool for creating a straight edge
  • Step ladder if needed to access the roof space
  • Torch or lamp for lighting
  • Sturdy kneeling board to lay across beams
  • Broom handle or other long non-electrical conductive poker (not metal)
  • Gloves, dust mask and long sleeves to reduce temporary irritation
  • Ceiling insulation batts
    Follow these steps to ensure you correctly install insulation in your ceiling:

    1. Measure and calculate your insulation requirements
    • Measure the distance between your ceiling joists to determine what width ceiling batt you need. Measure to the centre of the joists and measure them all as distances may vary.

    Joist centres

    Batt width size required

    450mm wide

    430mm batts

    600mm wide

    580mm batts


    For odd distances, our Batts can be easily trimmed using your knife and straight edge to fit odd.

    • Select your desired R-Value.
      R-value is a measure of the insulation batt's resistance to heat flow.  The higher the R-value the slower your home will heat up in summer and the more heat will be retained in winter.
    • Roughly measure the area you need to insulate. You can either measure the area or check your house plans for the dimensions. Then work out the m2 area you need to insulate.
    • Divide the area to be insulated by the coverage per pack (for the insulation batt you have chosen). Round it up and that’s how many packs you need.


      1. Pre Installation Checks
      • To be safe, turn off power at the fuse box before commencing installation, and place a warning tag on it so nobody mistakenly turns it back on while you’re working.
      • Don’t choose a hot day to install – roofs can heat up to 70 degrees. If it’s summer, do the job early in the morning before the heat has built up. And take some water up there with you, it can be a thirsty job.


          1. Installing the insulation in place
          • Take your sealed packs into the roof and open them there. Open the packs with your utility knife, drawing it down the side of the pack.
          • Only stand on the joists or use your kneeling board. Position your kneeling board over at least two joists for maximum stability. Do not stand on ceiling plasterboard
          • Start from the outside of the roof and work your way back to the access point.
          • Push your batts out towards the eaves so the first batt is 50mm across the top plate (edge of the outside wall) but remember the 20mm gap between roof and batt. Use your poker to push them into limited access areas.
          • Fit the batts snugly between the ceiling joists onto the ceiling plaster, and butt them up against each so they’re firm but flat.
          • Fill in any gaps with offcuts or trim a piece off another batt.

          Click here to download the Bradford Insulation step by step installation instructions.