How often should you re-caulk your windows and doors?

Failed seals let in drafts, water, and waste heating/cooling.

Failed sealant lets wind-driven rain into the wall around the frame, where it rots timber and saturates insulation without ever showing inside until the damage is advanced. The energy loss is smaller but constant, and around a whole house the gaps add up to a meaningful hole.

1. Inspect on a cold or windy day. Draughts are far easier to feel when there is a temperature difference. Run the back of your hand around each frame.
2. Remove all the old sealant. This is most of the job. Use a sealant removal tool or a sharp knife and take it back to clean substrate. New sealant over old fails quickly.
3. Clean and dry the joint. Solvent wipe removes silicone residue, which nothing will adhere to. Let it dry completely.
4. Fit backing rod in deep joints. Foam rod fills the depth so the sealant bonds to two faces rather than three, which lets it stretch properly instead of tearing.
5. Mask both sides if you want a clean line. Tape, apply, tool, then pull the tape while the sealant is still wet.
6. Apply in one continuous pass. Push rather than pull the gun, keeping steady pressure and a consistent bead.
7. Tool the bead immediately. A wet finger or a spatula presses the sealant into contact with both faces. This step is what makes it stick.

• Cracking, shrinking or splitting along the bead
• Sealant that has lost adhesion and lifted from one side
• A draught you can feel at the frame edge on a windy day
• Staining, peeling paint or soft timber below a window
• Daylight visible at the frame perimeter

• Applying new sealant over old, which is the single most common error and guarantees early failure
• Using the wrong sealant: silicone cannot be painted, acrylic has poor movement capability, and polyurethane and hybrid sealants suit moving joints best
• Filling a deep joint solid with sealant instead of using backing rod, so it tears rather than stretches
• Sealing over rotten timber, which hides the problem while it continues
• Sealing weep holes at the bottom of frames, which are deliberate drainage and must stay clear

• South-facing elevations in the northern hemisphere, and north-facing in Australia, take the most ultraviolet and fail first
• Large temperature swings mean more joint movement and shorter sealant life
• Quality varies enormously: a good hybrid sealant lasts many times longer than the cheapest acrylic

If the timber beneath is soft, or the frame itself has dropped or racked, sealant is not the repair. That needs a joiner or window specialist.