How often should I check weatherstripping and caulk around my house?

There is no official schedule, so treat it as a habit: walk around the house once each fall before the heating season and check every exterior caulk joint and door and window seal, give the busiest doors a quick look in spring, and check again whenever water or a draft turns up. Caulk and weatherstripping wear out on their own timetable, and a short routine catches failures before they cost you heat or let water into a wall.

Why a routine beats a lifespan on the label

Caulk does not last forever, and it does not always fail where you can see it. A U.S. Forest Products Laboratory report states: "Caulk joints cannot be expected to remain functional indefinitely; leakage will eventually occur."^[3] It also notes that sealant joint failure can occur without obvious indication.^[3] The most common problem is adhesion: adhesive failure, where the caulk lets go of one of the surfaces it was meant to seal, is the most common failure mode.^[3]

Label lifespans are optimistic. The same report says no professional consensus exists on how long sealant joints in residential construction can be expected to remain functional,^[3] but professionals commonly believe their service life is usually shorter than 20 years.^[3] Its author adds that warranties of multiple decades cover only replacement of the caulking material, not the labor or damage from a failed joint.^[3]

How long the materials usually last

Quality and type matter. Virginia Cooperative Extension says cheaper products may last only a few years, while premium-priced caulks are normally designed to last 20 years or more.^[1] The Virginia Energy Savers Handbook rates the common types: acrylic latex at 10 to 20 years, silicone at 20 to 50 years or more, one-part polyurethane at 20 to 30 years, butyl rubber at 3 to 10 years, oil-based caulk at 3 to 5 years and rope caulk at 2 to 3 years.^[2] Rope caulk is a temporary seasonal sealant,^[2] so plan to replace it each year you use it.

Weatherstripping depends more on use than on age. Extension notes that the gasket type of threshold wears fast: this type of gasket wears quickly in high traffic areas.^[1] Foam tape on a door you open dozens of times a day will flatten much sooner than the strip on a window you never open.

When to check

Fall, before the heating season. This is the main check. ENERGY STAR observes that more than any other time of year, you notice your home's air leaks in the winter,^[4] and a windy fall day makes leaks easy to find before the bills arrive. Do it while the weather is still mild enough to recaulk outside.

Spring. A quicker look at the doors you use most, sweeps and thresholds, and any exterior joints that took a beating over the winter.

After a storm or a leak. Wind-driven rain finds failed joints. A water stain inside near a window or door is a reason to check the caulk and weatherstripping right away.

When you repaint. Paint prep is the natural time to cut out and replace old caulk on trim.

What to look for

Outside, start with the windows: "For windows, check the outside for any sign of caulking that has cracked or peeled."^[1] Look at door and window frames, corner boards and the places where pipes, dryer vents, hose bibs and wires come through the wall. Caulk that has gone hard, cracked, shrunk or pulled away from one side is done. Peeling paint around the window or door frame^[6] is another sign of a leak.

For doors, Extension suggests a dollar bill test: shut the door on a bill in several spots. "If it falls out or slips out easily, the weather-stripping should be repaired or replaced."^[1] Then try light, with the interior and exterior lights off: "If a helper inside the house can see light shining in, weather-stripping is needed."^[1]

Inside, check the places Extension lists as possible air paths: windows, doors, electrical outlets, ceiling fixtures, attic hatches and other places with a possible air path to the outside.^[1] On windows, make sure the locks close firmly; the handbook notes the lock holds the sashes firmly against the frame and reduces air leakage.^[2]

Fixing what you find

Small gaps are quick fixes. Extension says, "Generally, you can use caulk to seal openings up to ¼ inch wide,"^[1] and "For larger gaps, foam backing material should be put in place before caulking."^[1] Remove the old bead first; new caulk over failed caulk usually does not bond well. Follow the label on temperature. DAP's exterior sealant, for example, goes on between 40°F and 100°F and not when freezing temperatures are forecast within 24 hours.^[5]

Caulk is not a substitute for proper flashing. The Forest Products Laboratory warns: "Sealant joints should thus not be considered as acceptable substitutes for formed metal flashing."^[3] If water keeps getting in around a window or door no matter how often you recaulk, the problem is likely behind the trim.

In a house built before 1978, scraping old caulk off painted trim can disturb lead paint. If you hire it out, anyone paid to do work that disturbs paint in a home built before 1978 must be certified in lead-safe work practices.^[7]

Stop and call a pro if

• Wood around a window, door or threshold is soft, rotted or stained.
• Water comes in around a window or door even after fresh caulk.
• The joints that need work are on upper-storey windows or trim you cannot reach safely from the ground or a short ladder.
• You see mold on the inside of window frames or walls near the leak.
• The house was built before 1978 and the old caulk sits on painted trim you would need to scrape or sand.

For the repairs themselves, see how to weatherstrip a drafty door and where the biggest air leaks are. You can browse handyman services, handymen around Blacksburg and the other handyman answers. If a check turns up more than you want to fix, describe the window repair once and local businesses quote it.