Weatherstripping is used to block air leakage around doors and the operable parts of windows. Weatherstripping comes in a variety of shapes: flat strip, tube or V (i.e. V-strips), and can be designed to work under compression or by sliding along the joint. To be effective, the product must close the gap and not allow air to pass. Some products get hard - and less effective - in cold weather when you need them the most.
When choosing weatherstripping, consider the size of the gap to be sealed and the durability, ease of installation and finished appearance of the product. Look for products that are flexible and that spring back to their original shape quickly and easily. Avoid products that make it difficult to operate the window or door. When replacing weatherstripping, bring a sample of the old material to the store with you to ensure that you purchase the correct product.
A wide range of products is available in most building supply stores, including complete sealing kits. For the best quality weatherstripping, contact window and door manufacturers or installers.
Figure 3-5 Types of weatherstripping
Larger image
Table 3-4 lists the major types of products.
Table 3-4 Weatherstripping
Compression strips
Category
Application
Installation
Comments
Closed-cell foam (with or without vinyl covering)
use where there is a pressure stress: along the bottom of vertical sliding windows, around attic hatches or on hinged windows and doors
adhesive-backed
easy to install
available in rolls
available as a high-performance compressible polyurethane strip with its own carrier
good for irregular surfaces
vinyl may crack over time
Ribbed closed-cell rubber
as above
adhesive-backed
available in rolls
very durable
easy to install
good for irregular surfaces
less appropriate for long or varied gaps
Tubular stripping material
as above
has its own attachment or an attachment strip
installed with nails, staples or screws
rubber more durable than plastic
noticeable when installed
check for suitability of use in cold weather
Tension strips
Category
Application
Installation
Comments
Spring vinyl
use in the same applications as compression strips
also in sliding joints for double-hung windows and doors
adhesive-backed
easy to install
use small-format V-strip for narrow gaps such as tight-fitting double-hung windows
use large format for wide gaps
good durability
polypropylene type should be chosen instead of other plastics
Spring metal
generally used for doors
most effective under light compression
installed using small tacks
metal can permanently deform
potential to ice-up
Combination types
Category
Application
Installation
Comments
Spring-loaded, self adjusting
spring mechanism adapts to long unequal distances from the weatherstrip to the door or window
effective for doors and hinged windows
installed with screws through an attachment strip
can be used in conjunction with V- strips
cannot adjust to small irregularities
limited colours
highly visible
Magnetic-strip systems
magnetic strips on the frame and on the door/window
effective for doors and hinged windows
ensure a clean, smooth surface for installation of self-stick products
good durability
highly noticeable when installed
limited colours
for doors: works best on
may not provide good seal in cold conditions because of condensation and frost formation (i.e. the PVC case may stiffen and split)
Door bottoms, sweeps and thresholds
Category
Application
Installation
Comments
Door sweeps (attach to the door)
vinyl, pile, silicone or rubber sweep
screwed with a metal or plastic attachment strip
easier to install than a threshold
effective with low-pile carpet or no carpet
height variable attachment
some models have replacement seals available
more durable than thresholds, but often provide a less effective seal
some vinyl types are very flexible and more durable
Door bottoms
combination strips of vinyl, pile or compressible rubber
attachment strip fits over the door bottom
requires a clearance of 8 to 13 mm (1/3 to in.) under the door
more durable than thresholds, but often provide a less effective seal
Thresholds (attach to the floor or door frame beneath the door)
a vinyl rubber or combination metal/vinyl or rubber strip attached to the threshold
requires clearance below the door, see the manufacturer's instructions
can become damaged by traffic and weathering
some models have replacement seals available
provides an excellent seal
less durable than door sweeps, but a more effective seal
Other air barrier materials
Category
Application
Installation
Comments
Duct tape
approved foil and flexible plastic duct tapes can be used to seal seams of heating duct to reduce air leakage
do not use on heating equipment vents or chimneys
may require removal of paper backing to expose the adhesive
clean surfaces before applying
do not use common vinyl or cloth-backed duct tapes because the adhesive fails over time
use especially where ducts pass through unheated areas
Sheathing tape (i.e. red technical tape)
used to seal the seams of house wrap, wind barrier material and polyethylene air barrier material
try to place tape joints between building materials to help further secure it, if possible
very sticky adhesive
do not apply temporarily to finished surfaces because the adhesive may remain on the surface after the tape is removed
Electrical box air barriers
placed around electrical outlet and switch boxes before installation
equipped with a flange for sealing to the main air barrier
also act as a vapour barrier
seal the wiring hole with an appropriate sealant
Mastic putty
hole filler
usually applied around pipes and cabling on exterior walls
sticks or ribbons of putty are softened and pushed around pipes or cables on existing walls or furnace plenum
poor adhesion when the product dries out
do not use below grade or where subject to wetting
Mastic latex sealant
seals joints on heating, cooling and ventilation ducts
apply to cleaned joints with a brush or a cotton glove with non-latex liner (then discard!)
easy cleanup
good bond
not noticeable
water-based type has low to no fumes
Pot light covers (recessed light covers)
seals pot light fixtures to the top of the ceiling
installed from above with screws
some come with sealants on gaskets
designed for high temperatures
