Insulating the roof cavity in your home is one of the best ways to improve temperature regulation and energy efficiency. But when it comes to insulating the space between ceiling and roof, what type of insulation should you use for the best results?
Ceiling insulation and roof insulation are often used interchangeably in conversation, but there is a slight difference between the two. Here’s what you need to know about ceiling and roof insulation, plus a few tips to help you have a successful installation in your home.
What’s The Difference Between Ceiling And Roof Insulation?
Ceiling insulation is insulation that is installed in the ceiling, usually between the rafters. Roof insulation is insulation that is installed under the roofing material.
Ceiling insulation is usually a type of bulk insulation such as glasswool or polyester batts. Batts come precut to fit between the rafters of most Australian homes, but can be easily trimmed with a utility knife if needed.
Roof insulation is usually a type of reflective foil insulation which will help reflect radiant heat from the sun away from your home. Sometimes foil insulation can be combined with bulk insulation for a two-in-one product.
What’s More Important – Roof Insulation Or Ceiling Insulation?
The truth is, both roof and ceiling insulation play an important role in insulating your home. For the best results, they should be used in conjunction to reduce heat loss and heat gain.
Reduce Radiant Heat Gain With Reflective Roof Insulation.
As mentioned above, roof insulation is typically made from reflective materials which help reflect radiant heat from the sun away from your home. The reflective surface will also help trap radiant heat from sources inside your home during winter.
Slow Down Convection And Conduction With Ceiling Insulation.
Ceiling insulation is usually bulk insulation which contains millions of tiny air pockets inside its structure. These air pockets don’t conduct heat very well which reduces the transfer of heat into your home in summer and reduces the amount of heat lost during winter.
Understanding The Ideal R Value For Your Location
The R Value of an insulation product indicates how effective it is at slowing down heat transfer. The higher the R Value, the more effective the product will be and the more benefits you will experience.
Experts recommend a minimum of R4.0 for ceiling and roof insulation in warmer locations such as Perth and Brisbane. For cooler climates like Melbourne and Sydney, R5.0 or R6.0 is recommended. Alpine locations should upgrade to R7.0.
Get More Insulating Power By Upgrading To A Higher R Value
If your budget allows, it is recommended that you upgrade to the highest R Value you can afford. With more insulating power, your home will be better at regulating temperatures, making your living areas more comfortable all year round.
A higher R Value can also lead to greater savings on your energy bills. By resisting heat flow, insulation will make it more energy efficient when you use artificial heating and cooling appliances.
Best Roof And Ceiling Insulation Products For Australian Homes
- Glasswool batts – glass wool batts are one of the most affordable and popular choices for ceiling applications. Made from recycled glass materials, they offer excellent thermal properties, are moisture resistant and don’t attract vermin.
- Polyester batts – polyester batts are a premium product made from recycled plastic materials. They contain no breathable particles and are suitable for homes with dust allergies.
- Roofing blanket with foil facing – this type of product is a combination of both bulk insulation and reflective insulation which means it will help with convection, conduction and radiant heat.
- Reflective roof sarking – reflective roof sarking can be installed under the roofing material to act like a second skin for your home. It will help reflect radiant heat away and improve the weather resistance of your home.
How To Install Insulation Batts In The Ceiling
Ceiling insulation can be installed from below if the ceiling plaster has not been hung yet or from within the ceiling cavity if access is possible. If you cannot access the ceiling cavity through a manhole, it may be possible to access it by removing some of the roofing material, for example sliding back a few tiles.
Insulation batts should be installed between ceiling rafters. They should fit snugly without gaps but take care not to compress them as this can compromise their performance. You can trim the batts to fit better and any off cuts can be used to fill in small gaps.
Ceiling insulation should be installed under electrical wires where possible. Adequate gaps should be left around downlights and any type of ventilation.
Installing Roof Sarking On An Existing Home
It is possible to install reflective roof sarking in existing homes by removing roofing tiles or metal sheets and dismantling the roof battens. Galvanised staples or nails can be used to secure the sarking in place on the rafters.
Installing sarking on an existing home can be dangerous and should be carried out by a professional installer to ensure compliance with local regulations.
