Roof
The roof of your home is one of the most essential elements in keeping your family warm, dry, and safe. Keeping all parts of your roof well maintained over time will help ensure it is secure and still able to do its job.
How a roof is maintained dramatically affects its lifespan. Adequate care and maintenance specific to your roof type is essential to ensure it remains an efficient insulator, safeguards against structural deterioration and maintains its tolerance and resistance to external influences.
Some common roofing issues are listed below.
Metal roof coverings
Age related timber contraction and expansion can result in the buckling and twisting of roof coverings. Additionally, where fixings loosen over time and inadequate allowances for thermal movement exist, further timber contraction and expansion can occur. It is important to regularly maintain your roof coverings as any areas that are subject to the risk of potential water ingress can result in further damage, such as rot to framing timbers, water damage to interior linings or even corrosion of steel.
For more information, visit:
BRANZ - Profiled metal roofing buckling or twisting(external link)
Roof membrane
Some roofs with rubber membranes are often reported to have ‘popped’ visible fixings. With older butyl roofs the ply substrate was nailed rather than screwed and glued as in modern techniques. Often, these ‘popped’ visible fixings occur because of heat shrinkage around the fixing. The heat causes the already loosened fixing up above the surface of the roof.
Punctures, impacts or tearing in roof coverings can often be attributed to aged related timber movement. However, these can also result from persons walking across the roof as some substrates are not suitable for foot traffic, whilst others are inherently brittle in nature (aged concrete tiles for example).
For more information, visit:
BRANZ – Sheet membrane roofing – deterioration along substrate joints(external link)
BRANZ – Sheet membrane roofing – lifting of sheet joints(external link)
BRANZ – Sheet membrane roofing – impact or puncture damage(external link)
Painted or stained roof coverings
Paint damage can occur from high exposure to the New Zealand sun and our various and everchanging seasonal temperatures. Paint cracking will often initially appear on bends and folds in roof sheeting while run off from lead flashings can cause staining to roof coverings as can soot and particulate emissions from nearby flues or chimneys.
For more information, visit:
Resene – Painting roofs – a how to guide
(external link)BRANZ – Painted profiled, steel roofing – paint damage(external link)
Rippling across a roof
A rippling effect (also known as undulation) across roof surfaces can often occur because of inadequately sized rafters and strutting supports for the span and weight of roofing material in place. It can also occur where roof framing has been previously damaged or cut (i.e. to fit a flue for example) and not adequately re-framed or where load-bearing walls below have been removed without adequate lintel and framing supports being installed.
For more information, visit:
BRANZ – Concrete or clay tiles – roof sagging(external link)
Concrete tiles
In older rimu ‘framed’ roofs, undulations often occurred soon after construction due to frames being loaded up with heavy concrete tiles while still wet and thus sagging under the weight. This effect was often worsened due to insufficient propping being in place whilst the timber dried out. Rimu is incredibly strong once dry but quite prone to deformity when wet.
Wind can also have an impact on tiled roofs, especially where the materials are reaching the end of their functional life. Dislodged tiles from high wind, capillary action and water tracking can also result in leaks. This wind driven water ingress is worsened by poor flashing mechanisms, aged, fatigued or poorly aligned tiles.
For more information, visit:
BRANZ – Concrete or clay tiles broken or cracked(external link)