Guide to house roof leaks, repairs, maintenance and reroofing

What roofing materials are commonly used in Australia?

Closter says Australia's most popular roof materials are terracotta and cement tiles, and metal, with each material having its strengths, along with drawbacks – especially as the materials age.

Colorbond

Known for its durability and aesthetic appeal, Colorbond is a metal roofing material that is popular for new builds and roof replacements. It has a colourfast coating and comes with a guarantee against fading. It is available in many colours and profiles, making it a versatile option for different architectural styles. Closter says the standard thickness for Colorbond roofing sheets is 0.42mm, but for flat roofs, he recommends a thicker 0.48mm sheet to prevent denting and provide extra strength.

Terracotta tiles

These tiles are durable and can last a long time with proper maintenance. They are prevalent on period houses in Melbourne’s leafy suburbs. However, Closter warns the tiles can become brittle towards the end of their lifespan. “If your terracotta tiles are old, don’t try to inspect the roof yourself or climb up there to rescue a ball; you could end up putting a hole in the roof,” he says. “You need to be a skilled tradesperson because it can be dangerous.”

Cement tiles

These tiles come in various profiles. Flat tiles are more prone to leakage than other tiles, and these tiles should have sarking paper under them to avoid any unwanted leaks. Regular maintenance, such as cleaning and inspecting for cracks or damage, is essential to ensure the longevity of these types of tiles. However, this is a job for professionals because the tiles are prone to breakage.

Galvanized iron

This material was commonly used until the late 1970s and early 1980s. It has since been replaced by more modern materials.

Slate roofs

Slate roofs are highly specialised and require professional handling. Closter advises against attempting any DIY work on slate roofs due to the risk of damage.

Zincalume

A zinc-coated aluminium product (55 per cent aluminium and 45 per cent zinc). This combination provides excellent corrosion resistance and helps to increase the lifespan of the roofing material. Zincalume is more affordable than Colorbond but only available in a standard grey colour.

Signs you have roof issues

Closter says common signs that a roof may need repairs include leaks, sagging, rust, and water pooling. He says regular maintenance, such as cleaning gutters and checking roof penetrations, is essential to prevent issues.

• Leaks - Visible leaks or water stains on the ceiling are clear indicators of roof issues.
• Blocked gutters - Blocked gutters can cause water to overflow and damage the roof and walls.
• Sagging - A sagging roof can indicate structural problems and should be inspected immediately.
• Rust - Rust on metal roofs or gutters can indicate deterioration and potential leaks.
• Water pooling - Water pooling on flat roofs can lead to leaks and structural damage.
• Deteriorating roof penetrations - Check for deteriorating seals around roof penetrations such as plumbing vents, skylights, and air conditioning units.
• Loose or missing tiles - Loose or missing tiles can expose the roof to water damage.
• Damaged flashings - Flashing refers to the flat metal pieces that direct water away from areas such as roof seams, joints, and the edges of the roof. Flashings that are deteriorating or not properly sealed can lead to leaks.
• Age - An old roof may have multiple issues and require more frequent repairs or replacement.

What factors do I need to consider if I need a new roof?

If you are considering a new roof, either for a new build or for reroofing, here are some important factors to keep in mind:

• Roofing materials - Different materials have varying lifespans, costs, and maintenance requirements. 
• Roof design - The architectural design should be suitable and compliant with regulations. Flat roofs with multiple penetrations can lead to leak issues.
• Box gutters - Be cautious with box gutters, especially in leafy areas. Box gutters can accumulate leaf debris, leading to blockages and water ingress into the property. Closter says regulations and codes for box gutters have changed, making it costly to bring older systems up to current standards.
• Maintenance - Regular maintenance, such as cleaning gutters and checking roof penetrations, is essential to prevent issues.
• Regulations and codes - Ensure that the roofing work complies with current regulations and codes to avoid costly upgrades in the future.
• Professional inspection - Have a roof professional inspect the roof every 8 to 10 years to identify potential issues early.

Can moss and lichen cause roofing issues?

Closter says moss and lichen growth can cause several issues, including erosion of the protective coating on the tiles and structural damage. If moss and lichen grow in the joints between tiles, that can create a damming effect that slows down water flow and causes it to overflow into the roof space.

There are several things that roof professionals can do to prevent moss and lichen growth on your roof:

• Regular cleaning - It’s important to remove debris, leaves, and other organic materials that can promote moss and lichen growth. 
• Trim overhanging branches - Trim any overhanging branches to reduce shade and moisture on the roof, as moss and lichen thrive in moist, shady areas.
• Install zinc strips - Install zinc strips near the ridge of the roof. When it rains, zinc particles will wash down the roof and inhibit moss and lichen growth.
• Chemical treatments - Use chemical treatments specifically designed to kill moss and lichen. Caution is required if you do this yourself. You need to follow the manufacturer's instructions and take precautions to protect nearby plants and the environment.
• Pressure washing - For severe infestations, pressure washing can be effective. This is a highly dangerous activity and should only be carried out by a professional with the right safety equipment.

How do I check if my roof is ready for solar panels?

Going solar is a great way to help reduce your energy bills. If you’re thinking about getting solar panels installed, then it may be prudent to get the integrity of your roof checked by a roofing professional first. Your roof must be strong enough to support solar panels and racking. RACV Solar installs solar systems on tin, cement and terracotta roofs, but not slate, which is often too fragile.

Secondly, check your roof is big enough for solar panels. You'll need at least 25-35m² for a 5kW system. While north-facing solar panels work best, the team at RACV Solar can advise you on how they can position panels to get maximum sun. 

Once your solar system is installed, the solar panels should self-clean when it rains. However, it’s a good idea to get them checked and cleaned regularly, especially in drier months. Over time your panels may collect dust, debris or bird droppings which can reduce energy production.

Roofing safety and best practices for maintenance

Working on a roof involves several safety concerns, and you should always consider your personal safety first. Ladder falls inside and outside the home can cause serious injury.  
 
If you have any roofing issues or need your gutters cleaned, consider getting a professional to do the job. They have the expertise and protective equipment to help prevent falls and deal with fragile roof surfaces.

Do not attempt any DIY roofing work during adverse weather conditions, such as rain, wind, or extreme temperatures, which can all increase the risk of accidents.

Be aware that working near power lines or electrical installations poses a risk of electrocution. It is essential to be aware of the location of electrical cables and avoid contact with them. Repairing a roof or installing a new one often requires the services of fully qualified electrician to disconnect and reconnect the power supply. 

Finally, roofs may contain hazardous materials like asbestos, which can pose health risks if disturbed. Proper precautions should be taken to handle and dispose of these materials safely.