Metal roof leaks

Why are my metal roof screws leaking, and how are they fixed?

Metal roof screws leak when the rubber washer under the head stops sealing. Heat movement loosens them, the sun wears the washer, and screws driven too tight or too loose fail early. A fix is a re-tightened or oversize replacement screw, not surface sealant. Old roofs may need all the fasteners replaced.

By Josh Hildebrand, owner of Coastline Roofing · Florida license CCC1331076 · November 7, 2026

You found a stain or a drip under a 5V crimp or corrugated metal roof. The cause is often a few screws, and there is a right way to fix them.

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The basics

Why are my metal roof screws leaking?

Exposed screws leak when the washer under the head stops sealing. The usual causes are loosening from heat movement, a cracked or worn washer, and screws that were driven too tight or too loose.

Some metal roofs are held down with screws that go through the face of the panel. People call these exposed fastener roofs. 5V crimp and corrugated panels are the usual examples. Each screw has a rubber washer under its head that seals the hole. On a roof with thousands of screws, a small number of failed washers is enough to cause a leak.

Sheffield Metals, a maker of metal roofing coil, calls leaking "one of the most common problems" of exposed fastener roofs. The Florida Roofing and Sheet Metal Contractors Association (FRSA) cites screws and faulty washers as a common cause of metal roof leaks.

The fix is often small compared with replacing a roof. The catch is finding the right screws and fixing them the right way, and a dab of caulk on top is not it. We explain that below.

If you are not sure the leak is at a screw at all, start with our guide to what to do right now when a roof is leaking. Coastline installs 5V crimp metal roofs, and Coastline repairs metal roofs too. See our roof repair page.

Leak under a metal roof?

Coastline repairs metal roofs and sends a written photo report that shows what failed. Coastline installs 5V crimp and 24-gauge standing seam metal roofs. Coastline Roofing works all over Florida (license CCC1331076).

Call (941) 896-7793 or text your town and a photo.

Causes

What makes metal roof screws leak?

Six causes show up again and again in the trade sources.

Heat movement

Metal panels expand when hot and shrink when cool. FRSA says this repeated motion stresses the screws and enlarges the holes, so screws loosen and back out of a wood deck. Sheffield Metals calls the result fastener withdrawal.

A worn washer

Sheffield says the gasket under the head breaks down from sun faster than the metal screw does. SFS, a fastener maker, says screws older than 20 years are on borrowed time and that most will not last past 30.

Driven too tight

Over-tightening can crack, cup or displace the washer, according to FRSA. The Metal Construction Association (MCA) says it can also deform the panel and create a pocket where water collects.

Driven too loose

An under-driven screw does not compress the washer. The MCA says under-tightened screws do not seal and are likely to leak, and they let the panel move when it should stay put.

The wrong screw

SFS says a screw without enough corrosion resistance can rust before the panels wear out. Mismatched metals speed up corrosion. A screw that is too short may not hold in the deck.

Too many or too few screws

SFS says too few screws let panels flutter and work loose, and too many create extra holes and stop panels from moving. Spacing should follow the plans. See metal roof rust on the coast for the corrosion side.

Finding it

How do you find which screw is leaking?

Look for water marks first, then work outward. The stain inside often sits near the screw but not always right under it.

Roof work is risky. We would rather you check from the inside and the ground than climb a metal roof. These steps use no ladder.

Check the attic during or just after rain
Look for drips, damp wood or wet insulation. Take a photo with something in the frame for scale. Our guide to how to check your attic for a roof leak goes step by step.
Note where the stain sits
Mark the spot relative to a rafter or purlin and the nearest wall. Water can run along a surface before it drips, so the entry point can be a bit uphill from the stain.
Look at the roof from the ground
Use binoculars to look for screws that stand proud of the panel, washers that look cracked, or rust streaks. Sheffield suggests checking for screws that are backing out, loose or rusted.
Count the age
Note how old the roof is. SFS says screws past 20 years are on borrowed time. If your roof is that old, one leak may be the first of several.
Get a written report
A roofer should find the fault and show you photos of it. Coastline sends a written photo report with every inspection, and Josh reviews it.

The repair

How are leaking metal roof screws fixed?

The right fix depends on why the screw fails. Loose screws get re-tightened. Damaged or stripped screws get replaced with a bigger one. Surface sealant is not a repair.

The MCA installation manual is clear about each case:

Under-driven screw. The MCA says this is typically and easily corrected by retightening to the correct tightness.
Damaged washer only. Replace the screw with one of the same size.
Over-tightened or stripped screw. The MCA says do not simply loosen it, because that opens gaps. Replace it, possibly with added sealant, a different gasket and a different size screw. If the panel is distorted or damaged, the panel may need to be replaced.
Stripped hole. Use an oversized screw. SFS says to go one size wider so the threads cut new grip, for example a #17 in place of a #14.

Why a dab of sealant is not the repair

The MCA manual says it is never acceptable to repair a failed fastener by putting sealant on the surface at the screw location. Caulk on top does not seal a loose, damaged or stripped screw. The screw has to be reseated or replaced.

SFS adds three tips. Mark the old screw pattern before you remove anything, so the new screws keep the original spacing. Match the washer to the application. And check the deck, the panel and the flashings, because a new screw cannot fix damage underneath it.

How often should you check? Sheffield says exposed fastener roofs need fastener checks up to two times a year, and SFS recommends twice a year and after extreme weather. After a hurricane or a hard storm is a natural time to look. Our hurricane season roof prep guide covers what else to check.

Repair or replace

When is it time to stop repairing screws and replace the roof?

When the screws, washers and holes are failing across the roof, not in a few spots, repair stops making sense.

Screw leak repair options for an exposed fastener roof
Option	What it is	When it fits
Retighten	Re-seat a loose screw to the right tightness, per the MCA	A few screws are loose and the washers are sound
Replace single screws	Remove the screw and put in an oversize one with a new washer, per the MCA and SFS	Scattered failures on a roof that is otherwise in good shape
Replace the screws across the roof	Pull and replace all fasteners and washers, keeping the pattern, per SFS	The roof is 20 years old or more and the washers are cracking everywhere
Change the roof type	Replace with panels that hide their fasteners, such as standing seam, per Sheffield	Repairs keep recurring, or the panels, deck or coating are failing too

Concealed fastener roofs, such as standing seam, hide their fasteners under the seam. Sheffield says they avoid the many penetrations that make exposed fastener roofs leak, and need less frequent checks. Coastline installs 24-gauge standing seam. Our standing seam vs 5V crimp guide compares the two.

One more thing to rule out: the roof slope. A Florida Building Code section, quoted in a Florida Building Commission binding interpretation, sets a minimum slope of 3:12 for lapped metal roofs without applied lap sealant. A roof installed flatter than its panels allow can leak at the laps whatever the screws are doing. That is a design problem a screw cannot fix.

If you want to know what a repair costs, our roof repair cost guide explains what sets the price, and how long roofs last in Florida helps you judge age. Coastline's written photo report shows what is wrong and whether it is a screw problem or something else.

Reviews

What homeowners say about working with Coastline

★★★★★

"Josh was very thorough diagnosing a hard-to-find leak on a tile roof, after 2 other roofing companies tried but failed to catch the problem. ... Great work at a fair price, great service."

Mark R.Leak repair, tile roof

★★★★★

"Loved how Josh used his drone to identify cracked and slipped roof tiles and sent us the photos. Photos also taken of completed work."

Felicity K.Tile roof inspection

★★★★★

"They did a good job on the repair so I would definitely recommend them."

Duke H.Roof repair, Florida Gulf Coast

FAQ

Sources

Want to know which screws are failing?

Coastline sends a written photo report of what is leaking and what it will take to stop it. Josh reviews every job.

Call (941) 896-7793 Text (941) 345-0072

Why are my metal roof screws leaking, and how are they fixed?

Why are my metal roof screws leaking?

Leak under a metal roof?

Heat movement

A worn washer

Driven too tight

Driven too loose

The wrong screw

Too many or too few screws

How do you find which screw is leaking?

Check the attic during or just after rain

Note where the stain sits

Look at the roof from the ground

Count the age

Get a written report

How are leaking metal roof screws fixed?

Why a dab of sealant is not the repair

When is it time to stop repairing screws and replace the roof?

Roof Repair

5V Crimp Metal Roofs

My Roof Is Leaking

Sources

Want to know which screws are failing?