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Volume 6   Issue 2                March 2005

To Seal or Not to Seal
by Amber Grayson

Most consumers donít spend much time thinking about the components of a door. But, we all should enjoy the fact that we donít have wind whistling through our door openings, or better yet, puddles of water or drifts of dirt and snow sitting just inside the door because of a small component called weatherstripping. Weatherstripping has become an integral part of exterior entry and patio doors, and certainly enhances their performance by reducing sound transfer, air and dirt infiltration, water resistance and, of course, improved energy performance. Not only is weatherstripping practical, it also lends well to the overall appearance of the window or door. Most types are available in a variety of colors.

Donít Let the Air In 
For perspective, consider this: measurements of a non-weatherstripped door show the space around the installed door or window can allow large amounts of air to flow into and out of the building. This is known as infiltration and can include air, water, dirt or other contaminants from the outside. If a typical 36-inch door does not have weatherstripping around it, the open space could be as much as 9 square inches. Thatís a pretty large hole to leave open in a home or business.

Commonly, window and door design engineers begin working with weatherstripping manufacturers early in the design process to incorporate the type and number of weatherstrips in their new products. Factory applied or installed weatherstripping on doors is commonplace on most entry doors and windows. 

Choosing the right weatherstripping products will be key in achieving the window and door manufacturersí overall performance objectives, including energy savings. Although advancements have been made making weatherstripping last longer, replacement is not a huge expense, nor is it difficult for a home or business owner to do.

Selection Considerations
When selecting weatherstripping for your doors and windows, consider this:
Resistance to wear by abrasion or friction: For example, the bottom of a door will receive more wear than the bottom of a window sash. Therefore, each will require different types of weatherstrip;
The opening type and material to be weatherstripped. Wood, vinyl or aluminum opening? Will it require self-adhesive, slide in/inserted, or nailed in place protection.
Size of gap or opening to be covered: There are many different types of weatherstripping and each is suited for a certain gap size;
Appearance: Will it be hidden or visible when the door or window is in use? Is it available in color matching to complement the door or window?;
Durability: A more expensive weatherstripping that lasts longer can often be
a more economical choice up front;
Exposure to weather: Some types of weatherstripping are not suitable for moisture infiltration applications as they wick water and cause the weatherstripping to deteriorate or grow mold; and 
Ease of installation: Does it require special tools, or dismantling the door or window to install?

Material Types
What is it made of? This is a tough question to answer easily. There are so many different kinds of weatherstripping. Letís start at the top of the line weatherstripping available for multiple applications. Foam weatherstripping is a foam-type filler inside of a skin that provides high- quality and long-lasting service in the most demanding conditions. When selecting a foam weatherstrip, determine if water infiltration is a problem. If moisture is a common problem, you should select a weatherstrip that is non-wicking; in other words, it doesnít soak up water that could make the weatherstrip rot or mold in place. The construction of skin and foam weatherstrip can possess additional features such as being weldable and recyclable, some provide excellent UV-resistance as well. Foam gaskets and seals come in a plethora of sizes and colors to fit most window and door applications.

Pile weatherstripping, which looks like rows of fibers and fins on either a self-adhesive strip, insertable or kerf-mounted strips, and T-slot pile also have a place in protecting from air and dirt infiltration. Ranking high on the list, these products are mostly hidden in the interior of windows and doors. Pile weatherstripping is also available in a variety of colors and can be ordered in custom lengths, or reeled for factory insertion into doors and windows. Pile insertion machines are available to assist door and window extruders with the insertion of the pile weatherstripping into their vinyl windows and doors. This type of machine makes the insertion process very fast and economical.

Pile weatherstripping also comes in plugs. Dust plugs commonly are seen at the corners of doors to bridge any larger gaps that are created during installation.

Of course, there are the other types of weatherstripping that also serve a valuable purpose. Metals, vinyl, felt, polyurethane and neoprene also are used in certain applications. Vinyl and felt flaps are easy to install and can be used just about anywhere on a window or door, but they are usually visible and may not be as durable as some other type of weatherstripping. Metals, such as bronze, copper, stainless steel and aluminum, are relatively low cost, durable, and usually used between the door and jamb. Since metals are more rigid than urethane or plastic weatherstripping, they may make door operation more difficult and are less suitable for uneven gaps. Metals are slightly more difficult to install in double-hung windows than the less rigid products. Aluminum is used frequently as a stabilizer in other weatherstripping materials. 

Weatherstripping is sold typically by the linear foot. When measuring, be sure to measure the width and depth of the gap as well and factor in manufacturer recommendation for compression. Some weatherstripping comes in different widths and thicknesses, and if itís too thick, it may interfere with the latch or locking mechanism on the window or door. If itís too narrow, it may not be fully effective in preventing infiltration.

Weatherstripping is an effective way to reduce or eliminate air, dirt, water and other contaminates around doors and windows. Here in the Midwest, where I was born and reared, that includes snow infiltration in the winter and mosquito infiltration in the summer. 

Amber Grayson serves as marketing coordinator for the Amesbury Group in Sioux Falls, S.D. 

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