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How to insulate a ceiling

A bag of insulation batts and the tools required to complete this project

Overview

Good insulation in your ceiling keeps your home warm in winter and cooler in summer. It can also help you save on energy bill. We'll teach you when is the best time to install insulation, how to cut it to size and some handy hints to make the job easier and safer.

Steps

1Tips before you start insulating your ceiling

Make sure the power is turned off before you start insulating your home. You should also work well away from any electrical wires in the ceiling space. Keep the insulation away from any lights to prevent it from catching fire. It's best to install insulation in the morning before it gets too hot in the roof space. Always wear coveralls, gloves, dust mask and safety glasses because some insulation can be irritating to your skin.
A bag of insulation batts and the tools required to complete this project

2Measure and cut the insulation

Wearing your safety gear, use your tape measure to measure the distance between the ceiling joists. Remember not all of the distances between the ceiling joists will be the same, so check them all. Using these measurements, cut your first piece of insulation to size with the utility knife and straight edge.
A person measuring the distance between joists in a ceiling

3Installing the insulation

Standing on your step ladder, feed the first piece of insulation between the ceiling joists until it is laid flat. Make sure to keep it away from any lights. Keep measuring, cutting and installing until all of your roof has been covered. Keep any of the insulation off-cuts until you have finished the job, they can come in handy to fill in small gaps between the joists.
A person wearing protective gear standing on a ladder to install an insulation batt between joists in a ceiling
Health & Safety

Asbestos, lead-based paints and copper chromium arsenic (CCA) treated timber are health hazards you need to look out for when renovating older homes. These substances can easily be disturbed when renovating and exposure to them can cause a range of life-threatening diseases and conditions including cancer. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer or visit our Health & Safety page.

When following our advice in our D.I.Y. videos, make sure you use all equipment, including PPE, safely by following the manufacturer’s instructions. Check that the equipment is suitable for the task and that PPE fits properly. If you are unsure, hire an expert to do the job or talk to a Bunnings Team Member.