Home roof insulation for metal roofs

A new insulation product is set to combat condensation in metal roofs - combining glass wool with reflective foil laminate to eliminate condensation in metal roofs.

Metal roofs are often difficult to insulate, due to their propensity to gather condensation - and of course excess moisture can lead to rusting. However, there is a new variety of home roof insulation on the market for homes that is set to eliminate the condensation problem.

"You have to insulate under a metal roof in order to reduce the dew point in the air, so that the underside of the metal gets warmed up," says Ray from the roof insulation expert CSR Bradford, which has released a product called Anticon, a glass-wool blanket that that is faced with a reflective foil laminate.

While glass-wool insulation and foil insulation are frequently used on their own in a roof, the combination of the two in the Anticon product is particularly useful under metal roofs because it creates a total vapour barrier. "When it's installed, the seams are overlapped so that the vapour barrier is complete," says Ray. "With a normal insulation product you'll still get some moisture movement through the product, so the foil provides the difference. Combining the two materials means you've got both insulation properties and anti-condensation properties."

Anticon can only be installed in new homes or extensions, or when you are getting your house re-roofed. And unlike with many older types of home roofing insulation, it's best to get a professional to install it. "It gets put on underneath the metal roof, as the last thing," says Ray. "So, you put all the timber battens down, lay the Anticon on top, then pin the metal down. It's important that the insulation is in contact with the metal roof, as not only does it provide thermal properties, but it's also very good for acoustics. That's another reason why it's often used under metal. If you just use foil alone underneath, it's noisy when it rains and so forth."

The other good news is that Anticon isn't particularly expensive - despite being a specialized metal roof insulation it doesn't cost much more than standard glass-wool blankets.