Quick Answer
On exposed-fastener metal roofs, the rubber washers on each screw wear out over time from sun exposure and daily heat expansion, and screws can back out or be over- or under-tightened. That leads to leaks. The fix is to inspect the fasteners, replace worn or loose screws with properly sized new ones, and seal any damaged holes. Regular checks prevent most screw leaks.
Why Screws Leak
Each screw on an exposed-fastener roof seals with a rubber or neoprene washer. In San Antonio, UV exposure and daily heating and cooling slowly break those washers down.
- Washers dry out, crack, or flatten
- Screws back out as panels expand and contract
- Overtightened screws crush the washer
- Undertightened screws never seal properly
- Screws that missed the framing do not hold
Finding the Source
Water can travel along the underside of panels and framing before it drips, so a leak inside may not be directly under the problem screw.
A roofer will inspect fasteners in the area, check flashing and trim, and look for missed screws or damaged panel laps.
The Right Fix
Worn screws should be replaced with new fasteners that have fresh washers, often one size larger if the original hole is stripped. Each screw needs the right torque to seal without crushing the washer.
Smearing sealant over failing screws is a temporary patch that can trap water and make future repairs harder.
Other Common Leak Points on Metal Roofs
Not every metal roof leak is a screw. These areas are worth checking when tracking down a leak.
- Ridge cap and closure strips
- Flashing around chimneys and walls
- Pipe boots around plumbing vents
- Skylight curbs and flashing
- Panel laps where two panels overlap
- Valleys where debris collects
Preventing Future Leaks
Inspect exposed fasteners periodically, especially on roofs more than about ten years old. Replacing screws before they fail is far cheaper than repairing water damage.
If you want to eliminate exposed screws entirely, a standing seam roof uses hidden fasteners. We can repair your current roof or discuss an upgrade.
Frequently Asked Questions
How often should metal roof screws be replaced?
It varies, but fasteners on exposed-fastener roofs should be inspected regularly, and many need replacement after several years of sun exposure.
Can I just caulk leaking screws?
Caulk is a short-term patch. Replacing the fastener is the proper repair.
Do standing seam roofs have screw leaks?
Standing seam panels use hidden clips, so there are no exposed screws on the panel surface.
Contact Sanchez Metal Roofing
Phone: (210) 708-3308. Email: sanchezmetalroofing123@gmail.com. Address: 520 Fredericksburg Rd, San Antonio, TX 78201. Hours: Monday through Saturday 8:00 AM to 5:00 PM. Free roof inspections across San Antonio. Call (210) 708-3308.