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Roofing Considerations

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Roofing Considerations

by Pietro Scalise

Following are some key considerations when thinking about what to do with your roof...

  • Building a home can be one of the most stressful and frenetic times one can experience. Little thought can sometimes be given to crucial design choices and materials employed. This can be especially so when dealing with architects who do not devote adequate time to listen to a client or with project home builders who churn out standard designs void of character and innovation, let alone diverting to unique designs. To avoid pitfalls, a client needs to be empowered with as much knowledge about what roofing designs and materials are available and not be afraid to demand the unusual.
  • Before making any roofing decisions, whether for a new house or renovation, always check with the local Council about the regulations on the type of roofing allowable in your area.
  • When looking for a roofing contractor, ascertain they are licensed to carry out roof tiling. The Master Tilers, Slaters and Shinglers Association of New South Wales (MTSSA) can be a source of reputable tradespeople.
  • Regular inspections of the roof are a vital part of maintenance. Carry out inspections at least twice a year: once at the end of autumn when all leaves have fallen and then late spring when the heaviest rains have ended. Remove leaves and debris from gutters and valleys. If lichens, mosses and algae are growing, these can be eliminated with appropriate herbicide.
  • When renovating, always match new roof pitches, shapes and materials used with those of the original home. Doing so will prevent your extension looking like an extension.
  • When extending up, consider a design that will step back the upstairs from the front façade of the downstairs. This will break up the roof shapes into a softer, more pleasant overall effect.
  • During construction of your roof, never simply rely on the inspections of either Council or architect but contract an independent party such as a qualified building inspector to report in writing on the construction of this crucial component of your home.

Steel Roofing

  • Demand at least 25 years warranty for any steel roofing but make sure that your steel roofing does not come into contact with copper piping or lead flashings as these are incompatible with it and may render the warranty void.
  • Never use materials such as acetone, methyl ethyl ketone (MEK), toluene, thinners or commercial paint strippers as graffiti removers or cleaners.
    In cases where the rain does not clean the roof adequately, wash the surface with a mild solution of pure soap or mild non-abrasive kitchen detergent in warm water. The steel roof should be thoroughly rinsed with clean water immediately after cleaning to remove traces of detergent.

Concrete and terracotta tiling

  • In the case of a brick-veneer property, roof tiles can be fixed in place prior to the external bricklaying being carried out and vice versa but it is important that tilers don’t bed the ridge capping until the internal gyprock plaster board ceiling sheets have been fixed. If the capping is bedded down with cement prior to the plasterboard ceiling, the bedding cement can be open to cracking when the ceiling fixers nail the ceiling plasterboard sheets. The roof tiler needs to return after all tradesmen have completed their roofing work and the ceiling has been fixed.
  • It is important for the ridge capping, the intersection at the top of two slopes in a pitched roof that forms its apex, be bedded on a cement based mortar bed and allowed to dry followed by a coating of flexible pointing material of about 5 millimetres of thickness. The mortar bed can crack but the flexible pointing will absorb considerable movements without cracking maintaining the roof’s integrity.


  • Roof failure can have substantial consequences on the rest of the building. Water penetration can ruin ceilings and discharge water to the base of the home resulting in rising damp and settlement cracking. Therefore as a secondary barrier, roof sarking can greatly enhance the integrity of a roof. Sarking is not essential for water tightness but makes a sensible second line of defence against water leaks. Sarking will usually take the form of a reinforced foil placed and lapped over the whole area of the roof, between the rafters and the batten, prior to tiling.
  • Sarking, as well as providing an effective vapour and water barrier, provides acoustic and thermal insulation.
  • From within the roof space inspect the roof sarking for any tears, holes or missing areas.

Inspection checklist

  • Stained plasterboard ceilings are a clear indication that the roof structure is allowing water penetration.
  • See if there are any damaged, missing or tiles that have slipped downwards. Multiple tiles that have slipped may be an indication that the battens have deteriorated which means that the conditions of the structural components of the roof need to be examined.
  • Inspect metal-lined valleys for any possible signs of deterioration, corrosion or cracking and replace if necessary.
  • Ridge and hip tiles that have cracked need to be replaced re-bedded and re-pointed.
  • Where the roof tiles meet walls or chimneys examine the integrity of the flashing and fix if necessary.
  • Gutters and downpipes need to be clear of leaves and debris. Assess how well the free flow of water is to the downpipes.


  • Guttering carries the roof water to the stormwater system of the home. If gutters and downpipes need replacing, consider contractors that will extrude the guttering in continuos lengths to avoid joints that can be the Achilles heel of the system.
  • Guttering can be chosen from a multitude of materials such as copper and aluminium, zinc-aluminium alloys on their own or zinc-aluminium that has a colour baked on its surface. Copper, being more expensive up front, will never require replacing or painting.
  • Look for a gutter protection system that offers at least 15-year warranty on the workmanship and 25 years warranty on the materials employed.

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