If your home needs a new roof, you'll inevitably become embroiled in roofing conversations with your contractor. This is where you can get lost in the jargon. To help you engage in meaningful discussions around roof replacement, here's an explanation of various relevant terms.
The cladding is the outer material that covers the roof. It could be concrete, terracotta, or slate tiles. Alternatively, it might be Colorbond, Zincalume or a different kind of metal roof. A roof replacement involves replacing this cladding material. You can either replace like with the same materials — for example, replace concrete with concrete — or swap to a different substance.
What you need to bear in mind if you switch is the weightiness of the cladding. Generally, metal is lighter than tiles. Thus, replacing your roof with metal typically won't put undue stress on the building. However, going the reverse, from metal to a denser tile, will necessitate an examination of your home's structure. Inspectors will need to determine if the dwelling requires additional buttressing and reinforcement to carry the heavier roof.
The Roof's Structural Framework
The cladding sits on top of a skeleton framework, which is typically timber, though it can also be metal. You might hear your contractor mention rafters, battens, and ceiling joists. Rafters are angled beams that point towards the ground. Rows of horizontal battens hold the rows of tiles or metal sheets. Ceiling joists are the timber beams that form the floor or base of the roof cavity. The ceiling plaster attaches to these joists. Sometimes sections of this framework can rot and warp if the cladding has a hole and rainwater has seeped inside the crawl space. Thus, your roofers might need to repair or replace some of this supporting framework.
Your roof will have several openings to allow for elements such as chimneys, vents, and skylights. Flashing is the membrane that covers the join between the roof and the side of the protuberance. The purpose of flashing — typically using metal, plastic or rubber — is to seal the join and make it watertight. Sometimes the flashing material deteriorates through exposure to the elements.
During a tiled roof replacement, your contractor may discuss sarking. Sarking is a reflective foil laminate blanket that is spread over the roof framework, underneath the tiles. In extreme weather, driving rain can strike the roofing at such an angle to seep between the tiles. The sarking blanket prevents the water from getting any further. Reflective varieties deflect solar radiation away, which will keep your home cooler.