Project: Melbourne roof leak repair | Roof: Terracotta tiles with a skillion section | Works: Valley replacement, roof sarking and rebattening
A leaking tiled roof can have problems hidden beneath an otherwise intact surface. On this Melbourne roof leak repair project, our team uncovered two significant issues: a badly corroded metal valley with mortar and pointing along its edges, and a tiled skillion section without a suitable waterproof sarking membrane underneath.
The repairs focused on restoring clear drainage through the valley and adding secondary weather protection beneath the skillion roof tiles.
What we found beneath the roof tiles
Once the surrounding terracotta tiles were lifted, the condition of the old valley became clear. Heavy corrosion had developed along the areas beneath the mortar. Our inspection revealed extensive deterioration that was largely concealed while the tiles and mortar remained in place.
The stripped skillion section also exposed the roof framing and ceiling space, with no continuous sarking layer beneath the tiles in the affected area.
Why roof valleys should not be blocked with cement or pointing
A roof valley needs an open drainage path. Valleys collect rainwater from adjoining roof slopes and carry it towards the guttering. The metal tray extends underneath the cut tiles, allowing water from the tiles and their drainage channels to enter the valley.
Packing cement mortar or pointing along these edges can obstruct that natural flow. If the tile watercourses are blocked, water can back up or be diverted beneath the roof covering. Loose mortar can also collect further down the valley and contribute to blockages. Tile manufacturer guidance identifies blocked valleys and obstructed tile drainage channels as recognised causes of roof leaks.
Mortar in direct contact with metal also creates a durability concern. It can retain moisture against the valley and contribute to corrosion over time. Metal roofing manufacturer guidance advises avoiding contact between coated steel and mortar or concrete. On this roof, the severe corrosion followed the areas where the old mortar had been sitting.
This is why an open metal valley should not be filled or sealed with pointing in a way that blocks drainage. Bedding and pointing have an appropriate role on ridge and hip cappings, but the valley watercourse must remain clear.
Missing sarking beneath the skillion roof
The skillion roof needed protection beneath the tiles. Roof tiles shed rainwater, but their overlapping joints do not form a continuous waterproof membrane. Wind-driven rain can sometimes pass beneath them.
Roof sarking provides a secondary drainage layer, helping direct that moisture towards the roof drainage system before it reaches insulation, framing or ceilings. Correct installation and drainage detailing are essential to its performance.
On this property, the affected skillion section lacked that additional protection.
The roof leak repair works
- Lifting the terracotta tiles to access the affected skillion section and valley.
- Removing the old valley and the associated mortar and pointing.
- Installing a replacement metal valley with a clear, open watercourse.
- Installing roof sarking beneath the affected skillion tiles.
- Fitting new timber tile battens and relaying the tiles over the repaired section.
Roof leak repair photos: before, during and after
The old valley and hidden corrosion
Replacement valley and lower roof junction
Skillion roof repair progress
What the repairs achieved
These works replaced a deteriorated drainage component and added the missing secondary weather protection beneath the skillion tiles, while retaining the character of the existing terracotta roof.
For homeowners, this project highlights why identifying the underlying cause matters. A leak near a valley may involve hidden corrosion, blocked tile watercourses or missing underlay. An inspection beneath the affected tiles can reveal what needs repairing.
Arrange roof leak repairs in Melbourne
Contact Melbourne Roof Repairs to arrange an inspection. We can assess leaking valleys, terracotta and concrete tile roofs, and skillion roof sections, then explain the repairs needed for your property.
Arrange a roof inspection or learn more about our roof repair services and roof plumbing services.
