Gutter seams and end caps
Metal that expands and contracts in the sun. Gutter sealant goes on the water side of the seam.
Our pick: DAP Butyl-Flex, Geocel 2300 Tripolymer (Amazon)
Caulk by room
Roof & gutters
Elevate your caulk
Roofing caulk and gutter sealant are not the place to economize. They need to flex, stick to metal and asphalt, and hold up through years of freeze-thaw abuse, all while you're on a ladder hoping the neighbors aren't watching. Butyl rubber and polyurethane formulations dominate up here.
Your guideTroy, heights & heavy duty
Where to caulk in the roof & gutters
Every joint in the room, what goes in it, and why. The color bar matches the formulation.
Flashing edges and reglets
Where counter-flashing tucks into masonry, a roof-rated sealant keeps water from following it in.
Our pick: Geocel 2300 Tripolymer (Amazon), Sashco Through the Roof!
Exposed nail heads
A dab of roof sealant over exposed fasteners on flashing or ridge caps.
Our pick: Sashco Through the Roof!
Plumbing vent boots
Sealant can buy time on a cracked boot. Replacing the boot is the real fix.
Our pick: Sashco Through the Roof!
Chimney crown and cap
Small crown cracks take a masonry or crown sealant; flashing takes polyurethane.
Our pick: Sikaflex-1a (Amazon)
Dish and fixture mounts
Every lag bolt through the roof gets sealant under and over it.
Our pick: Geocel 2300 Tripolymer (Amazon)
The roof & gutters shopping list
Tubes worth a place in your cart for this room, and the joint each one suits. Price runs from $ (budget) to $$$ (pro grade).
| Product | Type | Best for | Why | Price | Buy |
|---|---|---|---|---|---|
| DAP Butyl-Flex | Butyl rubber | Gutters, flashing, shingle seams | Works wet or cold, sticks to asphalt | $ | Maker's page |
| GE Gutter Silicone 2 | 100% silicone | Metal and vinyl gutters | 30-minute rain-ready, wet or dry application | $–$$ | Maker's page |
| Henry 289 White Roof Sealant | Elastomeric latex | Flat and low-slope roofs, vents | Trowel or gun, UV-stable | $–$$ | Maker's page |
| Tremco Dymonic FC | Polyurethane | Fascia and soffit joints | Sag-resistant, high movement | $$$ | Check price on Amazon |
| GE Metal Silicone 2 | 100% silicone | Sheds, metal roofs, vents, RVs | Won't discolor chrome, bronze or nickel | $–$$ | Check price on Amazon |
Amazon links are affiliate links: if you buy through one, we may earn a small commission at no extra cost to you. It never decides what we recommend.
Seal a leaking gutter seam
Set the ladder safely
One foot out for every four feet up, on firm level ground, with someone nearby. Never lean on the gutter.
Clean the seam
Scoop debris, scrub off old sealant and rust with a wire brush, and let it dry completely.
Seal the inside
Apply gutter sealant along the seam on the inside, where the water runs, and feather it smooth.
Cover rivets and screws
Dab each fastener head. That's where drips start.
Let it cure, then hose-test
Give it the cure time on the tube, then run a garden hose down the gutter and watch.
Mistakes we see
- Using sealant instead of flashing. Sealant is a backup, not the system.
- Caulking a wet or dirty gutter.
- Using standard silicone on asphalt shingles; many silicones don't bond well to asphalt.
- Working on a wet, icy, or scorching roof.
How long it lasts
- Check it
- After fall leaf drop and after big storms.
- Redo when
- Drips at seams, stains on fascia, or cracked sealant.
- Typical life
- Years, if the metal was clean and dry when it went on.
Roof & gutters questions
Is roof caulk a permanent fix?
Sealant is maintenance. Failed flashing, cracked boots, and worn shingles need repair or replacement.
Can I apply roof sealant when it's wet?
Some roof sealants are rated for damp or wet surfaces; most sealants aren't. Only trust the tube.
When should I call a roofer?
Anytime the roof is steep, high, or wet, or the leak is under the shingles. No caulk is worth a fall.
More answers in the full FAQ, or let the Caulk Finder pick for you.
