10/10/2026
1. Attic first. Trace the stain upslope, checking rafters, sheathing, and insulation for dark streaks, rusted nail tips, or compressed insulation. A flashlight at night shows daylight through gaps.
2. Check the usual suspects. About 90% of leaks come from penetrations and transitions, not the field of the roof:
• Plumbing vent boots (cracked neoprene is the number one offender)
• Chimney, step, and counter flashing
• Valleys, especially where debris or moss builds up
• Skylight curbs and flashing
• Wall-to-roof junctions and dormer sidewalls
• Exposed or backed-out nails
3. Look at the surface. Slipped, cracked, or lifted shingles, failed sealant, and moss lifting tabs, which is common across the Fraser Valley.
4. Water test if it's not obvious. Hose the roof in sections, starting low and working upslope, with someone watching the attic. Isolate one area at a time, or you'll never know what actually leaked.
5. Use tech when needed. Moisture meters and infrared scans find wet sheathing and insulation that you can't see.
Don't just patch the stain. A dab of caulk on the wrong spot buys you one dry week and hides the real problem. If the sheathing is soft or the underlayment is shot, it's a repair at the source, or a section replacement, not another bead of sealant.
Leak showing up? Call Spartan Roofing. We'll find it, show you where it's coming from, and give you a straight answer on repair versus replacement.