Flashing Failures: The Hidden Cause of Most Roof Leaks
Roof Plumbing Perth is the metalwork that seals every junction on a roof and failed Roof Plumbing Perth is behind a huge share of persistent Leaking Roof Repairs Perth. Here's where Roof Plumbing Perth fail, why it's so often missed and how it's fixed for good.
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Roof Plumbing Perth are the least glamorous part of a roof and the most frequent reason water gets into a house. Nobody asks about them. Almost nobody can point to one.
They are the strips of metal that waterproof every junction where the roof meets something else. Get them wrong and the best tiles money can buy will not save you.
Where they live on your house
Run your eye along the roofline. Anywhere a roof plane butts into a vertical surface, there is a flashing.
Apron flashings sit where a roof meets a wall head on. Step flashings run up a wall alongside a sloping roof, cut into a stepped shape to follow the pitch. Chimney flashings wrap all four sides of a chimney and include a back Gutter Replacement Perth or saddle to divert water around it. Skylights carry their own purpose made kits. Parapet flashings cap the top of a wall that rises above roof level.
Every one of those is a manufactured detail that depends on being installed correctly and staying put.
The four ways they fail
Movement is first. Buildings shift with the seasons, particularly on reactive clay and a rigid flashing fixed to two surfaces that move independently will eventually pull away from one of them.
Sealant perishing is second. Many flashings rely on a bead of sealant at the top edge where the metal is tucked into a mortar joint or chased into brickwork. Sealant is not a lifetime product. Fifteen years is optimistic in Perth sun.
Corrosion is third, mostly near the coast and mostly at cut edges and fixing points rather than in the middle of the sheet.
Bad original workmanship is fourth and more common than anyone likes to admit. Flashings lapped the wrong way so water runs behind rather than over. Chimney saddles left out entirely. Step flashings replaced with a smear of roof cement by somebody in a hurry twenty years ago.
Roof cement is not a flashing
We find it constantly. Somebody has trowelled grey mortar or bituminous compound over a failing junction instead of replacing the metal underneath.
It works for a season or two. Then it cracks, because it is rigid and the junction it is covering moves. Worse, it traps water behind it and hides the deterioration while that water works on the timber.
Removing old cement patches is often the first thing we do on a Leaking Roof Repairs Perth investigation. What is underneath is usually worse than the owner expected and always more informative.
Why chimneys cause so much trouble
A chimney is a masonry column punched through the middle of a waterproof surface and water runs downhill into the uphill side of it.
That uphill face needs a back gutter or saddle that collects water and throws it around both sides. If it was never installed, or has corroded away, water simply pools against the brickwork and finds a way in. Many older Perth homes with disused chimneys leak here and nowhere else.
Capping a redundant chimney properly solves it permanently. Rendering over the top does not.
How a flashing leak announces itself
Stains that appear high on an internal wall rather than in the middle of a ceiling are a strong hint. So are damp patches in an upstairs room directly below where a lower roof meets an upper wall.
Bubbling paint on a chimney breast is another. So is a wet patch that appears in one particular corner every single time it rains hard, without ever spreading.
Fixing it properly
A proper repair means removing the old flashing rather than covering it, checking what the water has done to the timber behind and installing new metal lapped and fixed the right way round.
It is not a large job on most houses. It is a job that has to be done correctly, because a flashing installed backwards looks identical to one installed properly until the first serious front arrives.
Lead, galvanised and modern coated steel
Older Perth homes frequently have lead flashings. Lead is soft, shapes beautifully around awkward brickwork and lasts a very long time. It is also worth stealing, which is occasionally how it disappears from a roof.
Mid century houses tend toward galvanised steel, which corrodes at cut edges once the zinc coating wears through. Contemporary work uses coated steel matched to the roof sheeting.
The important rule is not mixing them carelessly. Put dissimilar metals in direct contact with moisture between them and you set up galvanic corrosion, where one metal sacrifices itself to protect the other. The join fails long before either sheet would have on its own. Lead against modern coated steel is a common and avoidable example.
The junction people forget entirely
Patios, carports, verandahs and pergolas attached to a house after it was built are responsible for a disproportionate share of flashing leaks.
Somebody bolts a new roof structure against an existing wall. Waterproofing that junction properly means cutting into the wall, installing a flashing that laps behind the wall cladding or into a mortar joint and dressing it down over the new roof. That takes time and skill.
Frequently what happens instead is a bead of silicone along the top edge. It looks fine for a year. Then it shrinks, cracks and admits water directly into a wall cavity and the damage shows up inside the house rather than on the ceiling.
What we do when we find one
Old flashing comes out rather than being covered over. We look at the timber and masonry behind it, because water has usually been there a while and its condition tells us how long.
New metal is selected to suit whatever it will sit against, shaped to the actual junction rather than forced into shape, lapped so water runs over each joint instead of into it and mechanically fixed with sealant as a secondary defence rather than the primary one.
Call 0421 768 842 if you have a stain that appears in the same spot every heavy rain and never spreads. That pattern is a flashing until proven otherwise.
Common questions
How long should a flashing last? The metal itself often outlives the sealant holding its top edge. Twenty years is a fair expectation for the sealed detail. Coastal exposure at Cottesloe or Scarborough shortens that. Sheltered inland positions extend it.
Can flashings be repaired rather than replaced? Occasionally, where the metal is sound and only the termination has failed. More often the honest answer is replacement, because half the cost is access and labour and doing it twice wastes both.
My render is bubbling below a roof junction. Related? Almost certainly. Water entering behind a flashing runs down inside the wall and emerges wherever it finds a weakness. Render damage is frequently the first visible symptom of a roof detail failing above it.
Do you work on two storey homes? Yes. Height, pitch and edge protection get priced into the quote up front, not added afterwards. Ring 0421 768 842.Flashing work takes us into the character suburbs regularly. Subiaco, Shenton Park, Nedlands, Claremont, Peppermint Grove and Wembley have the chimneys, parapets and later additions that produce most of these faults.
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