Caulk by room
Taking it outside
Exterior caulk has to survive what the interior never will: direct UV, rain, wind, and temperature swings of 100°F or more between summer and winter. For siding and trim, go elastomeric or tripolymer (paintable). For masonry and stucco, choose a polyurethane or silicone. For joints that will move significantly, only a high-movement-rated sealant will last.
Your guideRosie, head caulker
Every joint in the room, what goes in it, and why. The color bar matches the formulation.
Wood and fiber cement move with the weather. Use a paintable, exterior sealant with a high movement rating. Fiber-cement makers publish approved sealants; follow them.
Our pick: DAP Dynaflex Ultra, Sashco Big Stretch
The classic repaint job. Stretchy and paintable.
Our pick: Sashco Big Stretch, OSI Quad Max
Rough, porous, and often wide joints. Polyurethane or hybrid with backer rod.
Our pick: Sikaflex-1a, Soudal Fix ALL
Every hole in the wall is an invitation. Hybrid sticks to almost everything; silicone is fine if you won't paint.
Our pick: Soudal Fix ALL, Gorilla 100% Silicone
Horizontal concrete joints get self-leveling polyurethane over backer rod.
Our pick: Sikaflex Self-Leveling
Small gaps get caulk. Bigger holes get stuffed with copper mesh and then sealed.
Our pick: Sikaflex-1a
Dirt and chalky paint ruin adhesion. Give washed siding a dry day or two.
Anything cracked or loose comes out. Scrape loose paint too.
Primer gives the caulk and the paint something solid to grab.
Rod for joints over 1/4 inch; then a paintable exterior sealant, tooled into the joint.
Paint when the tube allows. Painted sealant lasts longer in the sun.
Only with a product rated for it. Many sealants advertise a rain-ready time; check the tube and the forecast.
Polyurethane or a hybrid rated for masonry, with backer rod in wide joints.
Standard silicone won't hold paint. If it needs paint, use a hybrid, polyurethane, or paintable elastomeric instead.
More answers in the full FAQ, or let the Caulk Finder pick for you.
