Where Aluminium Roofs Show Up in Singapore Homes
Aluminium roofs are everywhere in Singapore landed property — over car porches, side patios, rear extensions, drying yards, and DIY conservatories. They are lightweight, cheap to install, and reasonably durable. They also leak in very specific, predictable places.
Almost every aluminium roof leak comes from one of three sources: failed sealant at fixings, joint failure between sheets, or flashing failure where the roof meets the main building wall.
Failed Sealant at Fixings
Aluminium roofing sheets are fixed to a steel or aluminium frame with self-tapping screws, each fitted with a rubber or neoprene washer. Over time, UV breaks down the rubber, screws back out slightly with thermal cycling, and a small gap opens between washer and sheet.
A proper rectification involves removing each old screw, cleaning the area, applying a fresh polyurethane or hybrid polymer sealant, and re-fixing with a new screw and washer. Skipping the cleaning step and just smearing sealant over old screws is the most common shortcut — and it lasts about a year.
Joint Failure Between Sheets
Where one aluminium sheet overlaps the next, there is usually a bead of sealant between them. That sealant ages, dries out, and cracks. Wind-driven rain then finds its way through the joint and runs along the underside of the sheet until it drips inside.
Proper joint repair means cleaning out the old sealant, applying a primer if the manufacturer specifies, and laying a fresh bead of high-grade polyurethane or MS polymer sealant. For aluminium roofs that have aged badly across many joints, sometimes the right call is a full liquid-applied membrane over the entire roof.
Flashing Failure
Where an aluminium roof meets the main building wall, there is usually a metal flashing tucked into a chase in the wall and dressed over the roof sheet. When the chase mortar fails or the flashing pulls loose, water enters along that line and tracks down the wall inside.
Repair involves cutting out old mortar, refixing the flashing, repointing the chase with weather-resistant mortar, and sometimes adding a sealant bead over the flashing-to-wall joint as a secondary defence.
Liquid Waterproofing Over Aluminium
For aluminium roofs that have multiple leak points and are no longer worth point repairs, a liquid-applied membrane over the entire surface is a legitimate option. PU and acrylic systems that bond to aluminium exist and can extend the roof life by 8 to 12 years.
Surface preparation is critical — the aluminium must be cleaned, degreased, lightly abraded, and primed with the system manufacturer's primer. Skipping any of those steps is the main reason liquid-over-metal jobs fail early.
When to Reseal vs Replace
Aluminium roofs in Singapore typically last 15 to 25 years before the metal itself starts to corrode at the edges and around fixings. If your roof is leaking but the sheets are still in good condition, resealing and reflashing is usually the right call — typical cost $1,500 to $5,000 depending on roof size and access.
If the sheets are pitted, dented, or showing white aluminium oxide bloom, replacement is the better long-term answer. Replacing an aluminium roof on a typical car porch runs $4,000 to $12,000. The specialists we partner with can advise on which makes more sense after a site visit.
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