Caulk by room

Windows & doors

Let it all hang out… then seal it up

A drafty window is basically just a polite hole in your wall. Window and door caulk needs to bond to multiple substrates (wood, aluminum, vinyl, brick), flex with temperature swings, and hold up for years without cracking. Polyurethane and elastomeric formulations are the go-tos for exterior applications; paintable acrylic for interior finishing.

Your guideZoe, windows, doors & drafts

Zoe, closing a polite hole in the wall.

Where to caulk in the windows & doors

Every joint in the room, what goes in it, and why. The color bar matches the formulation.

Exterior trim to siding

MS polymer / hybrid Elastomeric latex Polyurethane

Sun, rain, and constant movement. Use an exterior-rated, paintable sealant with a real movement rating.

Our pick: OSI Quad Max (Amazon), DAP Dynaflex Ultra (Amazon), Soudal Fix ALL

Frame to brick, stone or stucco

Polyurethane MS polymer / hybrid

Masonry is rough and porous and the joint is often wide. Polyurethane or hybrid grips it; use backer rod when the gap is over 1/4 inch.

Our pick: Sikaflex-1a (Amazon), Soudal Fix ALL

Interior casing to wall

Acrylic latex

Stops the draft you feel around the trim and cleans up the paint line.

Our pick: DAP Alex Plus (Amazon)

Door threshold and sill

100% silicone Polyurethane

Seal where the sill meets the jambs and the floor, keeping water from wicking under the door.

Our pick: GE Silicone 2 Kitchen & Bath (Amazon), Sikaflex-1a (Amazon)

Glass to frame

Specialty 100% silicone

Old wood sash takes glazing putty, not caulk. Clear silicone is fine on metal and vinyl stops.

Our pick: Sashco Lexel, Gorilla 100% Silicone (Amazon)

Weep holes and drainage gaps

Not a caulk job

The little slots at the bottom of vinyl and aluminum frames let water out. They are supposed to be open.

Never caulk weep holes.

The windows & doors 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).

Windows & doors caulk shopping list
Product	Type	Best for	Why	Price	Buy
DAP Dynaflex 230	Elastomeric latex	Window and door trim	Very flexible, resists cracking	$–$$	Check price on Amazon
GE Supreme Silicone Window & Door	100% silicone	Exterior window frames	UV-resistant, bonds to vinyl	$–$$	Check price on Amazon
Loctite PL Window, Door & Siding Sealant	Polyurethane	Exterior masonry gaps	Paintable, bonds to brick and stucco	$–$$	Check price on Amazon
DAPtex Plus Foam Sealant	Expanding foam	Rough openings and headers	Fills large gaps around frames	$	Check price on Amazon
Great Stuff Window & Door Insulating Foam	Expanding foam	Around window flanges	Minimal expansion, won't bow frames	$	Check price on Amazon
Tremco Spectrem 1 Silicone	100% silicone	Storefront glazing	Commercial grade, long service life	$$$	Maker's page
GE Advanced Silicone 2 Window & Door	100% silicone	Metal flashing and trim	UV-resistant, 40-year durability claim	$–$$	Check price on Amazon
OSI Quad Max Window, Door & Siding	Exterior sealant	Lap siding and J-channel	Strong adhesion, paintable	$$	Check price on Amazon
DAP Extreme Stretch	Elastomeric latex	Windows, doors, siding, trim	Very high stretch, gaps up to 3", ASTM C920 Class 25	$	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 drafty exterior window

Find the leaks
On a windy day, move a strip of tissue or a stick of incense slowly around the trim. Where it flutters, air is moving.
Cut out failed caulk
Anything cracked, hard, or pulling away comes out. New caulk on old caulk fails with it.
Clean and dry
Brush out dirt and cobwebs; wipe vinyl and metal with alcohol. Bare wood should be primed.
Backer rod for big gaps
Over about 1/4 inch wide or deep, press in foam backer rod first so the bead is the right depth.
Bead and tool
Work on a mild, dry day within the temperature range on the tube. Tool the bead into the joint.
Paint after the cure time
Most exterior sealants take paint once they've skinned or cured; the tube gives the window.

Keep reading

Mistakes we see

Caulking weep holes shut.
Painting a sash shut with caulk. The window has to open.
Using interior caulk outside. UV and movement will crack it in a season.
Filling deep gaps without backer rod, which leads to three-sided adhesion and torn beads.
Caulking in freezing weather or right before rain.

How long it lasts

Check it: Each fall, before heating season.
Redo when: You see cracks, gaps, or feel a draft.
Typical life: Years with a good exterior sealant; the sunny side wears out first.