Solar installation and roof penetrations: what good flashing looks like in Perth

Roof leaks after solar installation are a recurring complaint across Perth and Australia. When solar panels are installed on a tiled or metal roof, penetrations must be properly flashed and sealed to prevent water ingress. Here's what good practice looks like, what to check after your installation, and what to do if you suspect a leak has developed.

What is roof flashing and why does it matter?

Flashing is metal or rubber material that seals around roof penetrations (the points where conduit, cable runs, or mounting bolts penetrate the roof surface) to prevent water from entering the building. In solar installations, flashing is required at:

• Conduit entry points: Where the cable run from the roof panels passes through the roof into the ceiling space (typically a 40mm conduit with an aluminium or lead flashing plate)
• Rail mounting feet (penetrating systems): On tiled roofs, L-foot brackets typically bolt through the tile into the rafter below — each penetration requires a sealant/flashing treatment
• Tile lifters (on concrete or terracotta tile roofs): Mounting rails on tiled roofs often use spring-mounted "tile lifters" that allow the rail to sit above the tile surface without penetrating — these avoid roof penetration but require correct installation

Roof types and mounting methods in Perth

Concrete and terracotta tile roofs (most common in Perth):

The standard approach is to use tile hooks or L-feet that bolt through the tile into the rafter:

1. A hole is drilled through the tile
2. An L-foot or tile hook is bolted to the rafter through the hole
3. A lead or aluminium flashing collar is fitted over the bolt penetration
4. Roof tile sealant (typically silicone or bituminous flashing compound) is applied around the collar

Alternatively, spring-loaded tile lifters allow the rail to be attached above the tile without penetrating — preferred by many installers as it avoids roof penetrations entirely on tile roofs.

Colorbond metal roofing:

Rails attach via clamps to the standing seams or rib profiles of the Colorbond — no penetrations required. This is inherently watertight if done correctly. If rivets or screws are used (less common), each penetration must be sealed with butyl rubber or appropriate sealant.

What to inspect after installation

On the day of installation or the day after, inspect your roof from a safe vantage point (or ask the installer to walk you through each penetration before they leave):

For tiled roofs:

• Check that no tiles were cracked during installation (a common sign of rushed work)
• Confirm that flashing collars or sealant have been applied at every penetration point — ask the installer to point these out
• Inspect that displaced tiles have been re-seated correctly (lifting a tile to run cable, then not reseating it, is a source of water entry that may not show up until the first heavy rain)

For metal roofing:

• Confirm clamps are on the rib or seam, not on the flat pan (screws into the flat pan are a leak point)
• If any screws were used, confirm sealant has been applied

Conduit exit points:

• The conduit exit through the roof surface should have an aluminium or lead flashing plate fitted around it, caulked at the edges with appropriate roof-grade sealant
• A conduit that simply exits through a hole in a tile without flashing is an immediate water entry risk

What a roof leak from solar actually looks like

Solar-related roof leaks often don't appear immediately after installation — they may only manifest after the first significant rain, or after several wet seasons if a seal degrades slowly. Signs to watch for:

• Damp patches on the ceiling below where panels were installed (including areas beyond the array perimeter — water can travel along rafters before dripping)
• Rust staining on ceiling plaster near roof penetrations
• Musty odour in the ceiling space after rain

If you suspect a solar-related leak, note the location and timing (which part of the roof was most exposed during the rain event, how long after rain the damp appeared). This information helps determine whether the entry point is at a panel penetration or elsewhere.

Who is responsible for roof leaks after installation?

The installer is responsible for waterproofing their own roof penetrations. A workmanship warranty should explicitly cover any water ingress caused by the installation work.

If the installer is still in business:

1. Contact them in writing with photographs and description of the issue
2. Request they inspect and rectify within 14 days
3. Document all communication

If the installer has gone out of business, see Consumer Protection WA (1300 30 40 54) and the CEC complaints process for warranty claims through the installer's insurer.

What the installer is NOT responsible for: Pre-existing roof issues unrelated to the installation (cracked tiles from a previous storm, degraded flashing from a different penetration). If the area around the installation had pre-existing issues, this can complicate the claim — document the roof condition before and after with photographs.

Preventive checklist for before and after installation

Before installation, ask your installer:

1. What mounting method do you use on this roof type?
2. Will any tiles need to be drilled? If so, how are penetrations sealed?
3. How do you handle the conduit exit through the roof?
4. Is your work covered by your workmanship warranty for roof integrity?

After installation, inspect:

1. Check for any cracked tiles (photograph them immediately and advise the installer)
2. Confirm flashing is present at all penetration points
3. Confirm displaced tiles are re-seated
4. After the first significant rain, check your ceiling space (if accessible) and ceiling surface below the array for any dampness

Adding solar to an older tiled roof

Perth's concrete tile roofs installed in the 1970s–1990s are often approaching end of life (tiles become porous and prone to cracking after 30–40 years). Installing solar on an aged tile roof requires extra care — old tiles are brittle and crack more easily under foot traffic.

If your tiled roof is 30+ years old, consider getting a roof inspection before solar installation to assess tile condition. A reroofing project (replacing tiles with Colorbond) at the same time as solar installation avoids both the brittle-tile risk and the flashing complexity of penetrating tile roofs.

Roof penetration quality is one of the less visible aspects of a solar installation — you typically can't inspect it easily once the system is commissioned. The key protection is a workmanship warranty in writing, asking the right questions before installation, and doing a post-installation visual check. If you see unsealed penetrations or cracked tiles after installation, raise them with the installer immediately.