Tile roofing - both concrete and terracotta - is the most common roof type across Canberra's established suburbs. If your home was built between the 1950s and 2000s, there is a good chance it has a tile roof. These roofs are durable and long-lasting, but they are not immune to problems, especially in Canberra's harsh climate.
Understanding the common causes of tile roof leaks helps you make informed decisions about repairs and maintenance. Here is a detailed guide to the problems we see most often and how each one is professionally repaired.
Tiles crack for several reasons. The most common in Canberra are hail impact, foot traffic from tradespeople (antenna installers, solar panel technicians, or previous roofers who were not careful), thermal stress from repeated heating and cooling cycles, and age-related brittleness in older concrete tiles.
A cracked tile may not leak immediately - it depends on the size and location of the crack and how much water flows over that area. But over time, water works its way through the crack and into the roof cavity below. A tile at the bottom of a long roof plane or in a high-flow area like a valley will leak much sooner than a cracked tile near the ridge.
The fix: Individual cracked or broken tiles are replaced with matching tiles. We carry a stock of the most common tile profiles used in Canberra, including Monier, Boral, and CSR profiles. For discontinued tile profiles, we source reclaimed tiles or use compatible alternatives. Replacement of a single tile typically takes 15 to 30 minutes and costs between $25 and $60 including the tile.
This is the most common single cause of tile roof leaks in the ACT. Ridge caps are the triangular tiles that sit along the peak (ridge) and hips of your roof. They are held in place by a bed of mortar (bedding) and sealed with a flexible compound (pointing).
Over time - and much faster in Canberra's freeze-thaw climate - the pointing compound cracks, shrinks, and falls away. Once the pointing fails, rainwater enters through the gaps and flows directly into the roof cavity. You can often see cracked or missing pointing from the ground by looking at the ridgeline against the sky.
Traditional sand-and-cement pointing is rigid and is especially prone to cracking in Canberra's temperature extremes. Modern flexible pointing compounds (like Flexipoint) are much better suited to our climate because they expand and contract with temperature changes without cracking.
The fix: The old pointing is removed, the bedding is inspected and repaired or replaced as needed, and new flexible pointing compound is applied. For a full re-point of the ridge and hip caps on a standard 3-bedroom home, expect $800 to $2,000 depending on the length of ridgeline and the condition of the bedding underneath.
Bedding is the mortar base that ridge caps sit in. While pointing is the flexible seal on top, bedding is the structural support beneath. When bedding fails, ridge caps become loose, shift in wind, and create large gaps for water entry.
Bedding failure is a more serious issue than pointing failure alone. Signs include ridge caps that visibly sit crooked or at different heights, mortar fragments on the ground or in gutters, and ridge caps that move when touched.
The fix: Failed bedding requires the ridge caps to be completely removed, the old mortar cleaned away, new bedding mortar applied, and the caps re-set in the correct position. This is called re-bedding and is more labour-intensive (and more expensive) than re-pointing alone. A full re-bed and re-point typically costs $1,500 to $4,000 for a standard home.
Tiles can slip out of position for several reasons - strong winds, deteriorated tile clips or wire ties, broken nibs (the small hooks on the back of each tile that hold it on the batten), or movement in the roof frame. Displaced tiles create gaps where water enters freely.
Canberra's strong winds, particularly the westerly gusts in spring, are a common cause of tile displacement. Tiles on the windward side of the roof and along the edges are most vulnerable. We see this frequently in exposed suburbs like the higher parts of Belconnen and Gungahlin where homes are more exposed to prevailing winds.
The fix: Slipped tiles are repositioned and secured with appropriate clips or adhesive. If the nibs are broken, the tile is replaced. If multiple tiles have slipped in the same area, the battens underneath may need inspection to ensure they have not warped or deteriorated.
Valleys on tile roofs use metal flashing (valley iron) underneath the tile edges to channel water down to the gutter. Over time, valley flashings rust, corrode, or develop holes, especially on older homes where galvanised steel was used. Debris accumulation in valleys traps moisture and accelerates corrosion.
Valley leaks are often misdiagnosed because the water entry point is hidden under the tile edges. The leak may show up on the ceiling metres away from the actual valley, making it tricky to locate without experience.
The fix: Valley flashing replacement involves lifting the tiles on either side of the valley, removing the old flashing, installing new Colorbond or lead valley iron, and re-laying the tiles. This is a more involved job - typically $600 to $1,500 per valley depending on length and access.
Sarking is the membrane layer installed under the tiles and over the battens. It acts as a secondary waterproofing barrier - if water gets past the tiles (through a crack, gap, or wind-driven rain), the sarking catches it and directs it down to the gutter.
Many older Canberra homes - particularly those built before the 1990s - were built without sarking, or with a basic bituminous felt that has since deteriorated. Without effective sarking, any gap or crack in the tile layer allows water directly onto the battens and into the ceiling cavity.
The fix: Retrofitting sarking to an existing tile roof is possible but labour-intensive, as it requires lifting sections of tiles to install the membrane. It is most cost-effective to install sarking as part of a larger project like a roof restoration or re-bed and re-point job. For a new build or re-roof, sarking is now a code requirement in the ACT.
While lichen and moss do not directly cause leaks, they contribute to tile deterioration by trapping moisture against the tile surface. This accelerates the porosity of concrete tiles, which then absorb more water, which then freezes in winter and causes cracking. It is a slow but destructive cycle.
Moss growth is particularly common on south-facing roof planes and in shaded areas. Suburbs with heavy tree cover like Deakin, Curtin, and Hughes often show significant moss growth on tile roofs.
The fix: High-pressure cleaning removes moss and lichen and is usually the first step in any tile roof restoration. After cleaning, an anti-fungal treatment helps prevent regrowth. Keeping trees trimmed back from the roof reduces shade and moisture retention, slowing future growth.
A few cracked tiles and some failed pointing are straightforward repairs. But at some point, the accumulation of problems makes replacement more economical than ongoing repairs. Consider replacement when:
If you are unsure, book a roof inspection with us. We will assess the overall condition of your tile roof and give you honest advice on whether repair, restoration, or replacement makes the most sense for your situation. Call (02) 5133 5608 or book online. We cover all ACT suburbs, 7 days a week.
Roof plumbing covers gutters, downpipes, flashings, and valleys - all the components that move water off your roof. Here are the most common failures and how to spot them before they cause serious damage.
Garage roofs face unique challenges compared to the main house roof. Here are the most common garage roof problems in Canberra and how to address them.
Do not wait until water is dripping through your ceiling. Here are six early warning signs that your roof may be leaking, and what to do about each one before the damage gets worse.
Book a free estimate or call us for honest, no-obligation advice. We cover all ACT suburbs, 7 days a week.
Mon-Sun 9am-5pm - All ACT suburbs - 5-year guarantee
