|Caulk & Weatherstripping Tips
Warmed or air-conditioned air mixes with outside
air through gaps in your home's thermal envelope—exterior walls, windows,
doors, the roof, and floors. Such air leaks can waste large amounts of energy.
Most experts agree that caulking and weather
stripping any gaps will pay for itself within one year in energy savings.
Caulking and weather stripping will also alleviate drafts and help your home
feel warmer when it's cold outside. However, these two weatherization techniques
can't replace the need for proper insulation throughout your home.
Assessing air quality
Because caulk and weatherstripping limit indoor-outdoor air circulation, you
should assess your indoor air quality before you apply them. Some homes contain
dust, mold, carbon dioxide, and other indoor air contaminants. Sealing air leaks
in these homes, without proper ventilation, can also seal in their indoor air
pollutants. Therefore, any plan to tighten the thermal envelope of a home should
be accompanied by a look at your home's ventilation needs.
These facts does not cover indoor air quality
assessment and ventilation.
Detecting air leaks
You may already know where some air leakage occurs in your home, such as an
under-the-door draft that makes you want to put on socks. But you'll probably
need to search to find the less obvious gaps.
Look at areas where different materials meet,
like between brick and wood siding, between foundation and walls, and between
the chimney and siding. Also inspect around the following for any cracks and
gaps that could cause air leaks:
- Door and window frames
- Mail chutes
- Electrical and gas service entrances
- Cable TV and phone lines
- Outdoor water faucets
- Where dryer vents pass through walls
- Bricks, siding, stucco, and foundation
- Air conditioners
- Vents and fans.
Depressurize your home to help detect leaks. On a
cool, very windy day, turn off the furnace. Shut all windows and doors. Turn on
all fans that blow air outside, such as bathroom fans or stove vents. Then light
an incense stick and pass it around the edges of common leak sites. Wherever the
smoke is sucked out of or blown into the room, there's a draft. Or just turn on
all your exhaust fans (don't need to turn off the furnace) and try one of these
- At night, shine a flashlight over all
potential gaps while a partner observes the house from outside. Large cracks
will show up as rays of light. Not a good way to detect small cracks.
- Shut a door or window on a piece of paper. If
you can pull it out without tearing, you're losing energy.
For a more thorough and accurate measurement of
air leakage, you can hire a technician to conduct a blower door test in your
home. Blower doors are variable-speed fans with a frame and shroud that allows
them to fit inside a variety of door frames. Pressure gauges determine airflow
through the fan, as well as fan-induced pressure. The leakier a house, the more
airflow required to induce a pressure difference. When used as a diagnostic
tool, a blower door can also reveal the location of many leaks.
You can use a caulking compound to seal leaks in a variety of places throughout
your home, including around windows and door frames. In addition to plugging air
leaks, caulking can also prevent water damage inside and outside of the home
when applied around faucets, ceiling fixtures, water pipes, drains, bathtubs and
other plumbing fixtures.
You can use a caulking compound to seal leaks in
a variety of places throughout your home, including around windows and door
frames. In addition to plugging air leaks, caulking can also prevent water
damage inside and outside of the home when applied around faucets, ceiling
fixtures, water pipes, drains, bathtubs and other plumbing fixtures.
Caulk forms a flexible seal for cracks, gaps, or
joints less than 1 quarter-inch wide. Most caulking compounds come in disposable
cartridges that fit in half-barrel caulking guns (if possible, purchase one with
an automatic release). Some pressurized cartridges do not require caulking guns.
When deciding how much caulking to purchase, consider that you'll probably need
a half-cartridge per window or door and four cartridges for the foundation sill.
Caulking compounds can also be found in aerosol cans, squeeze tubes, and ropes
for small jobs or special applications.
Water-based caulk can be cleaned with water,
while solvent-based compounds require a solvent for cleanup. Caulking compounds
also vary in strength, properties, and prices.
Although not a high-tech operation, caulking can
be tricky. Read and follow the instructions on the compound cartridge. And save
yourself some trouble by remembering a few important tips:
- Clean all areas to be caulked for good
adhesion. Remove any old caulk and paint, using a putty knife or a large
screwdriver. Make sure the area is dry so you won't seal in moisture.
- Hold the gun at a consistent angle. Forty-five
degrees is best for getting deep into the crack. You know you've got the
right angle when the caulk is immediately forced into the crack as it comes
out of the tube.
- Caulk in one straight continuous stream, if
possible. Avoid stops and starts.
- Send caulk to the bottom of an opening to
- Make sure the caulk sticks to both sides of a
crack or seam.
- Release the trigger before pulling the gun
away to avoid applying too much caulking compound. A caulking gun with an
automatic release makes this so much easier.
- If caulk oozes out of a crack, use a putty
knife to push it back in.
- Don't skimp. If the caulk shrinks, reapply it
to form a smooth bead that will seal the crack completely.
Weatherstripping can seal leaks around movable joints, such as windows or doors.
You need to choose a type of weatherstripping that will withstand the friction,
weather, temperature changes, and wear and tear associated with its location.
For example, when applied to a door bottom or threshold, weatherstripping could
drag on carpet or erode as a result of foot traffic. Weatherstripping in a
window sash must accommodate the sliding of panes—up and down, sideways or
out. The weatherstripping you choose should seal well when the door or window is
closed while allowing it to open freely.
Choose a product for each specific location. Felt
and open-cell foams tend to be inexpensive, susceptible to weather, visible, and
inefficient at blocking airflow. However, the ease of applying these materials
may make them valuable in low-traffic areas. Vinyl, slightly more expensive,
holds up well and resists moisture. Metals (bronze, copper, stainless steel, and
aluminum) last for years and are affordable. They can also provide a nice touch
to older homes where vinyl might seem out of place. You can use more than one
type of weatherstripping to seal an irregularly shaped space. Take durability
into account when comparing costs.
To determine how much weatherstripping you will
need, add the perimeters of all windows and doors to be weather stripped. Then
add 5 to 10 percent to accommodate any waste. Also take into consideration that
weatherstripping comes in varying depths and widths.
Weather-stripping supplies and techniques range from simple to the technical.
Consult the instructions on the weather-stripping package. Here are a few basic
- Weatherstripping should be applied to clean,
dry surfaces in temperatures above 20° F (-7° C).
- Measure the area to be weather stripped twice
before you cut anything.
- Apply weatherstripping snugly against both
surfaces. The material should compress when the window or door is shut.