One of the most common misconceptions about metal roofing that refuses to be squashed is the myth that metal roofs aren’t good at keeping the heat out.
This myth persists because many of us only have experience with older metal roofs.
However, the metal roofing of today is worlds apart from the metal roof at your grandparents’ place.
Additionally, older insulation is much less effective at keeping the heat out than modern insulation materials.
If you’re planning a metal roof installation, you can’t ignore the question of insulation
While only one part of your roof, insulation is one of the most important, and can mean the difference between a pleasant home and a huge energy bill!
How roof insulation works
Insulation hardly needs an introduction. By now, most homeowners should be familiar with the role it plays in your home.
Effective roof insulation means less heat seeping into (and out of!) your home.
And that means less reliance on electric systems like air con and heating to keep your home at a comfortable temperature.
While it won’t block 100% of the radiant heat coming in, roof insulation will have a noticeable impact on your house temperature – not to mention, your energy bill!
However, when planning a metal roof installation, it’s important to understand the difference between the 2 main types of insulation:
Ceiling insultation: this is insulation installed directly underneath the roof itself
Roof blanket insulation: insulation installed immediately above the ceiling of the top story
While ceiling insultation is more expensive to install, it is the most effective type of roof insulator. Most radiant heat that does make it through dissipates in the crawl space.
Roof blanket insulation isn’t quite as effective, as radiant heat bleeds into your ceiling (and by extension, the rest of your home). That said however, it’s still effective – not to mention, it’s cheaper too.
Your house might even have both installed!
A lesser-known benefit – how roof insulation leads to peace and quiet
Another common myth we deal with on a daily basis is noise: “Metal roofing is too loud” is the first thing that many clients think when considering metal as a roofing material.
This is false. Metal roofing is no louder than any other roofing material.
And we have roof insulation to thank for that!
Insulation doesn’t just stop heat – it also helps reduce noise pollution by absorbing the bulk of sounds coming from your roof. If you live in an area with high rainfall, effective roof insulation is a must!
What is insulation made of?
Nowadays, most builders choose material combinations like:
- Polyester, natural wool and glass/rock wool
- Polystyrene and polyurethane
- Reflective metal foil
- Fibre, polyester and wool
If you’re unsure which material is best-suited for your roofing project, be sure to talk to Watermaster’s roof plumbers.
We’re intimately familiar each of these materials, how effective they are at blocking heat and sound, and how they can be best utilised.
Insulation vs sarking: what’s the difference?
As a metal roofing specialist, the first thing we start with when performing a roof installation is sarking. Much like your roof insulation, sarking is used to help maintain a comfortable temperature in your home.
That’s where the similarities end.
Unlike insulation, roof sarking does much more than keep the temperature level!
In addition to its insulating properties, sarking also doubles as protection against moisture.
Sarking acts as a “vapour barrier” – the way it works is highly technical, but modern sarking is made of impermeable materials. That way, any moisture that seeps through your home is stopped from entering your roof space and is instead directed outside the house.
Most of the time, the sarking redirects water to your gutters – for maximum effectiveness, you’ll need a healthy roof plumbing system.
This prevents the build-up of water vapour inside your home, reducing the risk of condensation and mould growth inside your roof.
Additionally, sarking also provides an additional layer of protection against ashes and embers – a potential lifesaver for homes in bushfire-prone areas!
Common roof insulation problems
New roof installations aren’t the only time you might need to worry about insulation. Even if you have an existing roof, you might need to think about your roof insulation if you:
Don’t have any roof sarking
Ideally, you’ll want both sarking and insulation in your roof. While insulation is great at stopping heat, it’s decidedly less effective at preventing moisture from getting in.
Don’t have complete roof insulation
For the best performance, your insulation will have to cover your entire roof.
In practice however, many tradies leave gaps in your roof insulation – perhaps they wanted to make space for air conditioner ducts or forgot to go back over the pathways they’d carved out for themselves.
Have asbestos insulation in your roof
The health problems associated with asbestos need no introduction. Lung cancer, asbestosis, mesothelioma… while asbestos is (theoretically) safe if left undisturbed, we recommend getting it swapped for something safer.
Thinking of a new metal roof? Better think of roof insulation (and sarking!) first
If you have any questions relating to your roof, we’re more than happy to answer.
A roof plumber in Melbourne like Watermaster can provide advice for every part of the metal roofing process, from initial consultation, to choosing roof insulation, to installation.