Weatherization

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Introduction

Floors, walls, ceilings, doors and windows all combine to make up the " envelope" of your home or business. Warm air leaking into the building during the summer and out during the winter can waste a substantial portion of your energy dollars. One of the quickest dollar-saving improvements you can make is to caulk, seal and weatherstrip all seams, cracks and openings to the outside since the gaps and leaks throughout a typical building add up to the same amount of air leakage as leaving a window open year-round. You can save 10% or more on your energy bill by reducing the air leaks in your home or business.

Technology Options

The first thing to do when weatherizing your home or business is to test for air tightness. On a windy day, hold a lit incense stick next to windows, doors, electrical boxes, plumbing fixtures, electrical outlets, ceiling fixtures, attic hatches and other locations where air is likely to leak outside. If the smoke stream travels horizontally, you have located an air leak that may need caulking, sealing or weatherstripping to help make your home airtight. Caulking seals the small cracks and holes in the envelope; weatherstripping seals around doors and windows.


Common Areas of Air Leakage
  • Drafty windows and doors
  • Holes or chases that lead down into the building from the attic
  • Holes or chases that lead up into the building from the basement
  • Gaps around plumbing and electrical penetrations
  • Gaps around the dryer vent
  • Air leaks around the bathroom or kitchen fan vents
  • Air leaks around recessed lights
  • Drafty attic door or hatch
  • Unsealed chases that open to the attic
  • Gaps around the chimney or furnace flue
  • Tops of walls that open into the attic space

Caulking
Eventually, all buildings need fresh caulking to fill gaps and cracks that may appear in walls and where different types of materials are joined. Checking and repairing caulk should be one of those maintenance projects that get done around the house every year or two. It not only saves on your heating and air conditioning bills, it prevents moisture and even insects from entering your walls.

Caulk is a pliable sealant that comes in large tubes that can be purchased at most hardware stores. Once the caulk is applied, it solidifies to fill gaps, cracks and spaces at joints and connections all around your home.

Look around the outside of your home or building for places that need to be filled in. If your heater is on, you may be able to feel drafts where warm air is escaping from cracks. In particular, look for gaps and holes around door and window frames, wall and roof vents and skylights. Look around outdoor faucets and where the gas pipes and electrical lines enter the house. Check the joints where siding joins at corners and where it meets the roof and the foundation, or where it meets the fireplace chimney.

There are caulks made specifically for concrete, for brick, for wood and even for glass and metal. Caulking can be made of pure latex, siliconized latex, polyurethane and other modern materials. Choosing the proper one for your task from the array of choices can be a daunting task. Ask someone at any hardware or home improvement store for advice. For most exterior uses around the house, you can use polyurethane caulk. It sticks to most materials and does not totally harden, but remains flexible, resulting in a longer useful life.

Backer Rod
Backer rod is a closed-cell or foam caulk typically used to seal leaks around window frames or rough door frames. You can press the backer rod into gaps with a putty knife or screwdriver.

Weatherstripping
Millions of doors across the country have little or no weatherstripping. Since most doors have a space — sometimes as much as a quarter inch or more — between the bottom of the door and the floor, large amounts of air can flow in and out of the space. For a typical 36-inch entry door, a quarter-inch small crack can leak as much air as a nine-square-inch hole in the wall.

Weatherstripping comes in many forms, and can be made up of a combination of materials such as wood, rubber, vinyl, metal and foam. Some types work well on both doors and windows, while others are more limited. These are the major designs you will find for use around the house or building:

    V-Strip — A long strip folded back on itself along its length, this type of weatherstripping can be made of either metal or vinyl. It forms a springy strip that bridges the gap between a door and the door jam — or a window sash and the window frame — to prevent the movement of air. Durable, long-lasting and easy to install, V-strips come with a pressure sensitive adhesive; once you have cut a strip to the proper length, you can stick it in place on the frame without the use of tools.

    Adhesive-Backed Foam or Tape — This material, made from rubber, foam or sponge rubber, can be installed in the same manner as V-strip to help seal doors and windows. Hardware stores sell it in various widths and thicknesses, and the tape is self-adhesive and easy to install. Simply cut the tape to the length you need with scissors, peel away the backing from the tape and stick it in place.

    The size and flexibility of tape make it well suited for blocking irregular-sized cracks. It wears out quickly, however, and needs to be replaced often—probably every one to two years.

    Felt — Felt, either plain or reinforced with a flexible metal strip, is sold in rolls that must be cut to length and stapled or tacked into place. Plain felt should be fitted in a door jamb so that the door presses against it; reinforced felt can be used to seal around both doors and windows. Felt traditionally lasts one to two years before it needs to be replaced. A variation on felt is pile, a carpet-like material that can be glued or tacked in place.

    Interlocking Metal — This is the best, most complex, most expensive weatherstripping. Think of two V-strips that are placed on the door and the door frame. When the door closes, the two pieces interlock to make a tight seal. Interlocking pieces are placed completely around the perimeter of the door — on the top, both sides and the bottom. Interlocking metal weatherstripping can be tricky to install properly, since both the door and the frame must be notched with a router. You may want to contract a professional to install it.

    Tubular Rubber and Vinyl Gaskets — Small tubes of sponge rubber or vinyl also can be used to weatherstrip around doors and windows. When the door presses against the gasket, it forms a tight seal. By pressing against these gaskets, the door forms a seal. The tubes come with a flange that can be tacked or stapled to hold them in place. Usually they last five years or more.

    Spray Foam — Spray foam expands after it is inserted into place, quickly filling gaps and small holes. Expanding spray foam is not intended for use near flammable applications (e.g., flue vents) or around window or door frames.

    Thresholds — The floor underneath a closed exterior door usually has a raised seal called a threshold. Many thresholds have weatherstripping built in. One style includes a tubular gasket seal built into the threshold that presses against the bottom of the door to keep out drafts. <

    Other threshold weatherstripping is mounted on the door itself. One style called a door sweep features a flexible flap that seals against the threshold.

    Wall Sockets / Outlets / Switches — Finally, do not overlook electric wall sockets and switches. Although they are not in the same category as doors and windows, the holes in the walls for electrical outlets and switches allow cold air into a house or space in the wintertime and leak cool, conditioned air in the summer. It is a good idea to purchase simple-to-install, pre-cut foam gaskets that fit behind the switch or plug plate to effectively reduce leaks.

Other Weatherization Methods
  • Install storm windows over single-pane windows or replace them with double-pane windows. Storm windows can double the R-value of single-pane windows and they can help reduce drafts, water condensation and frost formation. As a less costly and less permanent alternative, you can use a heavy-duty, clear plastic sheet on your window frame or tape clear plastic film to the inside of your window frames during the cold winter months. Remember, the plastic must be sealed tightly to the frame to help reduce infiltration.
  • When the fireplace is not in use, keep the flue damper tightly closed. A chimney is designed specifically for smoke to escape, so until you close it, warm air escapes — 24 hours a day!
  • For new construction, reduce exterior wall leaks by either installing house wrap, taping the joints of exterior sheathing or comprehensively caulking and sealing the exterior walls.
  • Install insulation. Consider adding insulation to reduce heating and cooling energy needs during extreme weather periods.
  • Consider hiring a professional contractor, who can detect smaller cracks by using a blower door and other tools.

Efficiency Benefits

Improperly sealed homes can squander 10% to 15% of a home or business' heating and cooling dollars and reduce the effectiveness of air-conditioning in the summer. By sealing the cracks and leaks around your home or building — and also adding insulation to U.S. Department of Energy’s recommended levels — you can save up to 20% on heating and cooling bills and make the space more comfortable.

Purchasing Tips

  • When choosing caulk, consider its life expectancy, how much it shrinks over time, whether or not it can be painted, and if it cleans up with soap and water or needs a solvent like paint thinner.
  • Weatherstripping should be evaluated carefully to make sure that it will fit around your doors and/or windows.
  • Ask your local retailer for advice on which products are best for your needs.