In years gone by, waiting out a rainstorm or windy weather under a metal roof could be a deafening experience, and the prospect of a banging, crashing metal roof often puts new buyers off the prospect. However, modern metal roofing technology is leaps and bounds ahead of the noisy steel sheeting of old, and a modern metal roof should be no louder than a comparable tiled or asphalt roof, while providing the same tremendous durability and strength of a traditional metal roof. Bear the following design considerations in mind when having your roof fitted, and you can save yourself a lot of future headaches (both figuratively and literally).
What kind of roofing sheets should I choose?
Though it may seem unimportant, the basic shape of the metal sheets that make up your roof can have a dramatic influence on how much noise they create in inclement weather. Corrugated metal is often used in wet, windy areas for its excellent drainage properties and resistance to impact damage caused by falling branches and other solid objects. However, corrugated metal also has a tendency to vibrate, and can also be tremendously noisy, particularly without proper underlayment or insulation.
To reduce noise levels, consider choosing a different kind of roof sheeting. Generally speaking, metal roofing with lower, flatter profiles tend to be less noisy as they vibrate less and catch less wind. Flat metal sheets can therefore be very useful, but they are less efficient at water drainage than corrugated sheets, and may require the installation of additional guttering and culverts to cope with heavy rains. Standing seam sheets are a good compromise, that provide adequate drainage while keeping the overall profile of the roof as low as possible.
What about underlayment and insulation?
Properly chosen and installed underlays are vital for any well-constructed metal roof; in addition to providing valuable sound insulation, they also serve as vapour barriers to prevent encroaching damp and mould reaching vulnerable roof timbers. Choose a durable, weather-resistant underlay material that hugs the underside of the roofing sheets closely, as this will help to muffle noises and vibrations. This layer of protection can be supplemented with special acoustical underlays, usually made from glass fibre, foam tiles or natural wool. While these materials are not waterproof and cannot be used alone, they are excellent at increasing sound insulation, and should be spread tightly underneath existing underlays.
Standard home insulation can also do a lot to reduce unwanted roof noise, and standard rolls and batts of fibreglass insulation can have a dramatic effect on sound levels. Spray foam insulation is also very effective, although wet application means that it may damage the undersides of exposed Colorbond roofing sheets.