Skylight replacement and flashing rebuild on a flat roof in Oakville
Flat-roof skylight had failed seals and corroded flashings; we rebuilt the roof-to-skylight tie-in for watertight performance.
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1. Remove the old skylight and inspect the curb
We cut away the interior trim, removed the glazing unit and unbuttoned the corroded metal flashing. The wooden curb was checked for rot; any wet or soft sections were planed back and sistered with treated pine to create a solid substrate.
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2. Strip and prep the membrane around the curb
We removed EPDM back to sound membrane and cleaned the deck of adhesive residue. The deck was primed with a manufacturer-recommended primer for the new membrane and allowed to flash off to ensure adhesion.
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3. Install new curb flashings and metalwork
Fabricated new counterflashing in 0.9 mm galvalume for corrosion resistance and formed a new gravel stop tie-in where needed. All metal laps were set with stainless steel fasteners and backed with butyl underlayment at transition points to prevent water tracks.
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4. Tie-in membrane and seal the skylight curb
We applied a new EPDM patch and heat-welded TPO-compatible transition membranes where the main roof was TPO; on EPDM roofs we used factory splice tape and a flange adhesive. The curb received a continuous adhered membrane wrap with 100 mm turns over the curb corners to prevent capillary action.
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5. Set the skylight and final flashing details
Installed a low-profile, double-glazed curb-mounted skylight with a thermally broken frame to reduce condensation. Final counterflashing was laced over the skylight flange and sealed with a polyurethane sealant; we left removable cap sections for future maintenance.
Frequently Asked Questions
How long does a skylight replacement and flashing rebuild take?
Typical jobs of this size take one to two days on the roof. If there’s rot in the curb or extensive membrane replacement needed, plan for an extra day for repairs and proper adhesive cure times.
How disruptive will work be to the house?
Most disruption is on the roof and at the curb; we keep interior openings covered and clean up daily. We don’t run demolition noise into the living space beyond removing the old skylight and interior trim.
How do I know when a skylight needs a flashing rebuild?
Signs are interior water stains, peeling paint below the skylight, visible rust on metal flashings, or membrane seam lift nearby. On low-slope roofs especially, a flashing tie-in failure is a common culprit and needs attention before more deck damage occurs.
Any seasonal issues for Oakville work?
Cold slows adhesives and sealants, so we avoid major membrane tie-ins in deep winter. Spring and fall give the best cure windows in Oakville’s climate; we do interim weatherproofing if work spans unstable weather.
Need a skylight fix on your Oakville flat roof?
We handle the flashing details, documentation and durable materials so the leak stays gone.
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