How to Retrofit Roof Insulation

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More than any other place in your home, it’s critical that the roof is insulated. That’s because the roof is responsible for the most heat loss and gain in a home – as much as 35%! When a building is being constructed, insulation can be installed simply as part of the building process. However, what happens when you want to insulate a pre-existing building or replace the insulation in an older home? And is it worth the investment?

Can You Retrofit Roof Insulation?

‘Retrofitting’ insulation means installing insulation in a home after it has been built as opposed to installing during the construction phase. Ceiling/roof insulation is fairly simple to install in existing homes provided there is enough room in the roof space for the necessary manipulation of insulation materials. The most convenient time to retrofit ceiling insulation is during renovations when the plaster has been removed, giving easy access to the ceiling cavity.

Choosing The Right Insulation Products

The ideal ceiling insulation for your home will depend on a number of factors including your geographical location, budget and personal preferences. Some of the most popular ceiling insulation products include:

Glasswool Ceiling Batts – Made from recycled glass materials, glasswool ceiling batts have excellent thermal performance and are easy to handle and great for DIY projects. To reduce noises from airplanes or heavy rain, you might consider investing in specialised acoustic ceiling batts to help create a quiet, peaceful indoor environment for your home.

Polyester Ceiling Batts – Pre-cut to fit most Aussie ceilings, polyester ceiling batts are made from recycled plastic materials and have none of the itch factor associated with some glasswool products.

Reflective Foil Insulation – With a thin layer of reflective foil, this insulation product is installed in the roof to help reflect radiant heat from the sun away from your home and is particularly effective for homes that receive a lot of heat in summer.

Whatever insulation product you choose, make sure you get the right R-Value based on your location. The higher the R-Value, the greater the thermal performance of the product, and the greater savings you can experience on your power bill. For ceiling insulation in Australian homes, we recommend a minimum of R4.0. However, if you live in a cooler location such as Melbourne, Sydney or Adelaide, we recommend upgrading to R5.0 or R6.0.

Replacing Vs Topping Up Old Insulation

In some cases it is possible to top up existing insulation with new insulation. However, if your existing insulation is damaged, mouldy or rodent-infested, you should get it removed before installing new ceiling batts.

Best Practices For Retrofitting Roof Insulation

When retrofitting ceiling insulation yourself, make sure you follow the following best practices to ensure you stay safe and get the optimal results from your insulation.

  • Ensure there are no gaps between ceiling batts.
  • Do not compress ceiling batts – this will compromise their performance.
  • Use appropriate safety gear, including safety glasses, gloves and dust mask. 
  • Avoid installing during the hottest part of the day as the roof cavity can become very hot.

For more information about retrofitting ceiling insulation, check out our guide at – RETROFITTING CEILING INSULATION GUIDE or get in touch with our friendly team.

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