The good, the bad, and the ugly of New Zealand roof cladding
A home’s roof performs two major functions. The most obvious is that it keeps the house and everything inside dry when it rains. It also plays a major role in insulating the house, holding in the heat during the winter and preventing the interior from getting too hot in the summer.
If the roof cladding begins to fail, moisture gets into the ceiling cavity. It can contribute to many problems there, especially if it goes undetected for a while. Water from a constantly leaking roof can eventually make its way right down to the foundations, resulting in:
- Higher power bills due to damaged insulation
- Mould and mildew
- Electrical fire risks
- Damaged walls, ceilings, and floors
- Rotten structural timbers
Therefore, if you’re thinking about buying a home, it’s a good idea to have the entire building, including the roof, professionally inspected.
Different types of cladding come with a range of pros and cons. Here are some of the more popular roof cladding systems we see on New Zealand homes.
What are the roofing materials in New Zealand?
Clay or concrete tiles have been a popular choice for many years. In fact, the clay tile is the oldest man-made roofing material. These tiles are very durable and resist fire and insect damage. However, they can crack when walked on, leading to leaks and maintenance challenges. They also require additional structural support because of their weight.
Tiles made of pressed metal offer the look of clay or concrete without the extra weight. Made with ZINCALUME® and coated with paint (and sometimes stone chip), they are sometimes confused with the old Decramastic tiles used in the 70s and 80s. These tiles had a reputation for weathering quickly, and some contained asbestos.
Asphalt shingles are relatively new to the New Zealand market. They come in two varieties, organic and fibreglass, and although fairly durable, may not last as long as other options. Their coating may eventually come off as they weather, and pre-80s tiles may contain asbestos. On the other hand, slate shingles are extremely durable and may last more than a century. However, they are extremely heavy, so need correct structural support.
Long-run steel roofing is durable, light, and fire-resistant. The main issues stem from improper installation and the historical use of lead-head nails, which tend to rust and cause leaks. If not properly installed, there is a risk of water seeping in at the joins or the roof lifting in high winds. The steel can also dent if hit by something heavy, like a falling tree.
If you want to buy a new home or are concerned about your current roof, get us to check it out. We’ll be able to advise if a roof has been replaced with tiles too heavy for the structure, is leaking from cracks or rusty nails, is likely to contain asbestos, requires expensive repairs, or has reached the end of its lifespan. Our comprehensive building inspections include free non-invasive moisture testing to determine if and where water is getting in.