Home Home improvement A Step-by-step guide to installing ceiling insulation

A Step-by-step guide to installing ceiling insulation

by Danny White

Wanting to install insulation in your ceiling? This is one of the best things you can do to make your home more energy efficient. Well insulated homes are more comfortable and save money on power bills year round.

Whether you’re planning on installing the ceiling insulation yourself or hiring a professional, it’s important to understand what’s involved. A little preparation goes a long way.

Follow the steps below for a safe and effective installation.

Step 1: Assess your current insulation (for existing homes)

If you are planning to install ceiling insulation in an existing home, you should first inspect the state of your current ceiling insulation. It may be very old and not very effective anymore, but if it is in fairly good condition you may be able to install new insulation over the old.

However, if the old insulation is infested with vermin, damaged or mouldy, you should remove it completely before installing the new insulation. Use gloves, safety glasses and a dust mask to do so. Vacuum up any debris that remains before starting on the new installation job.

Step 2: Choose the right type of insulation

The R-Value is the most important factor to consider when choosing which insulation product to install. The R-Value represents how effective the product is at resisting heat flow. So the higher the R-Value, the more insulating power it has.

Since the roof is responsible for a home’s greatest heat loss and gain, it’s important to install insulation with an appropriate R-Value. In fact, new Australian homes must meet certain R-Value standards according to their location.

For cooler climates like Melbourne, Sydney and Adelaide a minimum of R5.0 is recommended in the ceiling. For warmer places like Perth and Brisbane, a minimum of R4.0 is recommended. If your budget allows, consider upgrading to a higher R-Value for better temperature regulation inside your home and greater energy savings.

Step 3: Calculate how much you need

Before you start on your installation project, it’s important to know how much insulation you need to fill the space. Not getting enough can slow down your process as you will need to buy more part way through. Getting far too much can be a costly mistake.

To calculate how much insulation you need, first measure the ceiling space and calculate the area in m2 (length x width). Now multiple the area by 0.9. Reducing the area by 10% like this accounts for the ceiling joists.

Now divide the m2 of your ceiling space by the m2 inside the bag of insulation you are planning on using. This is how many bags you will need. Keep in mind different brands may package their insulation differently – there won’t always be the same amount of m2 in every bag.

Step 4: Gather your equipment

If you are planning on a DIY installation instead of hiring a professional, you will need to gather a range of tools and safety equipment before starting. These include:

  • Safety glasses – Safety glasses will protect your eyes from any insulation fibres as well as any dust and debris in the roof area.
  • Dust mask – Older homes can be particularly dusty in the roof, so it’s a good idea to wear a dust mask to protect your lungs.
  • Gloves – Some glasswool insulation products can cause irritation to the skin. Gloves will keep your hands safe from itchiness.
  • Long sleeves – Long sleeves can protect you from any itchiness that the insulation may cause.
  • Utility knife – Insulation batts come precut to fit between the rafters but you may need to cut some of them to fill smaller or awkwardly shaped areas.
  • Long stick/pole – A long stick, such as a broom, can help you push the insulation in place in hard to reach places.
  • Knee support – Kneeling on the ceiling rafters can be tough on the knees. Consider bringing a wooden plank or knee pads.

Step 5: Prepare for a safe installation

Avoid installing your ceiling insulation on a warm day because the roof space can get unbearably hot. Aim to get the job done early in the morning before the hottest part of the day. Don’t forget to take a large water bottle up with you.

As a safety precaution, turn off the power at the fuse box while you are in the roof.

Preload the roof with your unopened insulation bags. Insulation batts are compression packaged and will expand a lot when you remove them from the packaging. Putting them in the ceiling unopened will save you from dragging batt after batt into the roof.

Step 6: Install the insulation

Start from the point that is furthest from your roof hatch and work backwards. Make sure you leave at least a 20mm gap between the insulation and the roof. If your batts are going to touch the roof at the edge, consider buying a more compact “perimeter” batt that you can install around the edges.

The insulation should fit snugly and have an even height. Use your long stick to push any batts into place that are hard to reach. If you need to, you can cut the batts to better fit the space. Save the cut offs for any gaps you may need to fill.

Place insulation batts under any air conditioning ducts, pipes and electrical cables where possible. However, you must leave a gap around any downlights and ventilation openings – these should not be covered with insulation for safety reasons.

Step 7: Enjoy your newly insulated home!

Great work. Now that you have installed insulation in your ceiling, you can look forward to more comfortable temperatures inside your home and greater energy savings throughout the year!