Posted on: 27 October 2020Share
Rainwater can cause massive damage if it leaks into your metal roof. It can rot timber rafters, battens and other structural beams inside the crawl space. It can spoil insulation, causing mould and mildew to grow. Water can also dampen and cause dark patches on ceiling plaster — which, once waterlogged, can snap away from the ceiling joists. Another possible issue, blocked gutters, can lead to rainwater gushing over the sides and down your home's external walls. Dampness can permeate the walls and destabilise the building's foundations.
Thus, directing rainwater safely away from your home is a priority of metal roofing. Three aspects, in particular, affect the rainwater flow, preventing it from pooling and overflowing.
Steep roof pitches encourage rainwater to flow down the incline, along the gutters and through the downpipes. Flatter roofs, though, aren't such efficient water directors. At times, they allow rainwater to pool and form puddles, which can erode the metal and stress the building structure with the extra water weight.
When planning a metal roof, you may have noticed different profiles: some metal sheets display the classic orb wave, while others are angular with broad channels. Imagine if you laid each of these metal sheets flat and poured enormous amounts of water on top. Some, like the classic orb, can't contain a lot of water, which would tend to overflow in all directions. Other designs, with deep and broad channels, can control larger loads of water, and send it appropriately along the grooves.
Thus, a flatter roof pitch needs a profile that can contain more water than a more efficient steeply-pitched roof. Of course, this depends on your local rainfall also. Your roofer can tell you what profiles work with flatter roofs and which are suited to steeper pitches.
Around the perimeter of your roof lies the guttering, which captures and carries the rainwater away. The depth and breadth of guttering need to suit your local climate and rainfall. Bushfire prone areas should have closed gutters that don't gather leaves and debris which can catch fire. Heavy rainfall areas need ample gutters to cope with the water load.
Thus, when planning a new steel roof, your contractor will factor in the local climate and the roof pitch to arrive at a profile that will work for your home. Of course, the corrugations are decorative also, and within what's workable, you can select the design that you love the best.