What are Valleys and Flashings

We understand that a roof is more than just tiles and timber; it is a complex system designed to withstand the volatile weather of Sydney.

After over 32 years in the industry, we have learned that the success of that system rests entirely on how well its most vulnerable points are protected.

Valleys and flashings are exactly those critical points.

High Volume of Water

When rain falls on a pitched roof, gravity directs 80% of the water into the gutters.

In the internal corners where two roof sections meet, the water concentrates, accelerating into a high-volume torrent.

These points are under pressure during a heavy downpour and can cause rapid and destructive leaks.

What are Valleys and Flashings

Valleys are the long, V-shaped channels, typically lined with metal or a specialised membrane, that sit within the internal angle where two roof planes intersect.

Their sole purpose is to act as a high-speed drain, diverting the massive amount of water runoff that gathers in that corner.

Flashings are pieces of weather-resistant metal that create a seal around any vertical surface on the roof including chimneys, skylights, and vent pipes.

Flashings prevent water from seeping into gaps where the roofing material cannot provide a continuous barrier.

Why Valleys and Flashings Fail

It is generally a slow process.

• Corrosion and Rust: If older valleys and flashings were installed using non-corrosion-resistant metals, or if they are situated near the coast, they eventually rust.
• Debris and Blockages: Leaves, silt, and moss can accumulate in the V-channel of the valley. This debris traps water, allowing it to pool and rise above the edges of the flashing, forcing it under the tiles.
• Poor Installation: If flashings are cut incorrectly, shaped without sufficient overlap, or sealed with inadequate materials, they cannot handle the thermal expansion and contraction of the roof structure.

Expert Solutions

Our repair process for valleys and flashings addresses the underlying structural and material causes.

For a failing valley, this means stripping back the surrounding tiles, inspecting the timber battens beneath for any water damage, and replacing the entire valley.

For flashings, we guarantee a precise fit and use the highest grade flexible sealants that will move with the building.

If you suspect your roof needs attention, contact us today to arrange a visit at a time that is convenient for you.