1. Exterior Window and Door Frames
Unit 56
Exterior Window and Door Frames
Window Units • Exterior Door Units • Overhead Garage Doors

2. Preassembled window and door units are set in place by carpenters.
Window units and exterior door units are usually assembled at a factory or mill‑cabinet shop. The window and door units are delivered to a job site and installed by carpenters. Frames can be obtained unassembled. However, preassembled frames are usually ordered with window sashes and doors already fitted in them. See Figure 56‑1. Weatherstripping is often included and the exterior casing may also be attached.

3. Building codes often specify the minimum glass and venting area required for inhabitable rooms. In this example, the two windows provide 12 sq ft of glass area, which is 10% of the 120 sq ft floor area, and 6 sq ft of natural ventilation, which is 5% of the floor area.
Windows allow air and light into a building. Local building codes often specify the minimum glass and venting area required for inhabitable rooms. One building code, for example, recommends that inhabitable rooms be provided with natural light with an area not less than one‑tenth of the floor area, with a minimum of 10 sq ft. The code further states that inhabitable rooms must be provided natural ventilation. The area required for ventilation must be not less than one‑twentieth of the floor area or a minimum of 5 sq ft, whichever is greater. See Figure 56‑2. Openings for natural ventilation are not required if a complete mechanical ventilation system exists in the structure.

4. The tops of window and door frames are usually the same height.
Although windows are available in a variety of sizes, the window tops usually align with the door tops. See Figure 56‑3. Door heights are usually 6′‑8″ in residences and 7′‑0″ in public buildings.

5. Preassembled windows are constructed of a variety of materials including wood, aluminum, and aluminum-clad wood.
Various materials are used to construct window frames, sashes, and other window components. See Figure Wood is the oldest type of material used for window units. Aluminum, steel, and vinyl are also widely used. Aluminum windows are available in natural color or anodized with a colored finish. Vinyl‑ and aluminum-clad windows are also available. Vinyl- and aluminum- clad windows have a wood core and are wrapped with vinyl or aluminum, respectively.

6. Condensation will occur when certain air temperatures and relative humidity is achieved.
Airtightness of a window unit depends on the construction and fit of the sash and frame and installation procedures in the rough opening. Air infiltration occurs through cracks and joints around the window members, and often transmits moisture vapor to the interior of the building. When moisture vapor is transmitted, condensation on the inside of the window will occur when certain air temperatures and relative humidities are achieved. See Figure 56-5.

7. National Fenestration Rating Council (NFRC) labels provide information pertinent to window performance.
NFRC window labels provide information about the U factor, solar heat gain coefficient, visible transmittance, air leakage, and condensation resistance of a window unit. See Figure 56-6.

8. All windows have one or more sashes that fit into the window frame
All windows have one or more sashes that fit into the window frame. A double‑hung unit with two sashes is shown here.
A traditional double-hung window unit is shown in Figure The frame is composed of a top piece and two side pieces made of wood or metal. The width of these pieces is equal to the finished wall thickness. The sill is a slanted piece at the bottom of the frame. A sill permits moisture to properly drain away from the building. The space between the frame and the interior and exterior wall is covered by a casing. Aprons are placed below the finished sill and stool at the bottom of the frame. The window sash is the frame that holds the glass that fits into the window frame.

9. Fixed-sash windows are often used in combination with operable windows
Fixed-sash windows are often used in combination with operable windows. Fixed-sash windows are shown in the middle and at the top of this assembly, and double-hung windows flank the large window at the bottom.
Also called stationary windows, fixed-sash windows do not open or close. Since fixed-sash windows do not allow air movement through them, they are often used in combination with operable windows. See Figure 56-8.

10. A double‑hung window unit has upper and lower sash sections that move vertically in tracks provided in the window frame. The sashes for some double-hung windows can be tilted inward to allow cleaning of the exterior side.
Double­hung windows have upper and lower sash sections that move vertically in tracks provided in the window frame. See Figure 56‑9. Contemporary double-hung windows commonly have tilting sashes that allow cleaning the exterior side of the window from inside the building. Ventilation offered by double-hung windows is limited to 50% of the window opening.

11. Double‑hung windows require a balancing device to hold them in an open position.
Contemporary double-hung windows are fitted with balancing devices to hold the sashes in open positions. See Figure Compressible weatherstripping is sometimes used as a balancing device with lightweight windows. A sash weight and rope were used as a balancing device in the past.

12. Casement windows are hinged on one side
Casement windows are hinged on one side. The casement window shown here swings outward as the crank operator at the bottom of the window is turned. Sash locks are located along the inner edges of the window.
Casement windows are hinged on one side and have the same swing action as hinged doors. See Figure 56‑11. Ventilation from a casement window is 100% of the window opening. Most casement windows are installed to swing out from the building. However, they can also be installed to swing into the building. In addition to hinges, a crank operator and sash lock are installed on casement windows. Double or single casement windows are available.

13. Sliding windows often feature one movable and one stationary window.
Horizontal sliding windows move along tracks (or guides) located above and below the window. Sliding window units often consist of one movable and one stationary window. See Figure A three‑sash design consists of a fixed middle window and sliding windows on both sides. A locking device is the only hardware required.

14. Awning windows are hinged at the top and swing out at the bottom.
Awning windows are hinged at the top and swing out at the bottom. See Figure 56‑13. Awning windows are often combined with a fixed‑sash window. Sometimes a series of awning windows are placed in the same opening. Awning windows require hinges and a crank operator or push bar.

15. Sill pans may be installed at window or door openings to divert water to the outside.
Plastic flashing is commonly substituted for preformed metal flashing. Plastic flashing, such as sill pans, is less expensive than metal flashing, and is flexible and easily cut into various shapes. Sill pans are preformed polyvinyl chloride (PVC) plastic flashings used at the base of window and door openings to direct water that may have penetrated in or around the frames to the outside. See Figure Sill pans are available in multiple pieces to allow them to be adjusted to the desired rough opening width. For a two-piece sill pan, one side of the pan is positioned at the base of the rough window opening over the weather barrier and sheathing. Nails or staples are driven through the flange to secure the first piece in position. The same procedure is used for the second piece of the sill pan. A bead of sealant may be applied between the pieces at the lap joint. PVC cement can also be used to solvent-cement the two pieces together. The seam and nails or staples are then covered with membrane tape flashing before installing the window.

16. A beveled wood strip or dam strip may be installed below a sill pan to provide a slight angle.
When installing sill pans, ensure they are slightly angled to the exterior of the building to direct water away from the interior. In many cases, a beveled wood strip or dam strip may need to be installed along the inner edge of the rough sill to provide the proper angle for the sill pan. See Figure The strips may also be used without a sill pan directly underneath flexible membrane flashing.

17. Flexible membrane flashing is commonly used as window and door flashing.
Flexible membrane flashing is applied directly over the housewrap. Cut a piece of flashing approximately 1′ longer than the width of the rough opening. If necessary, install a beveled wood strip or dam strip along the inner edge of the rough opening. Peel the release paper from the flashing and position the flashing along the bottom and approximately 6″ up the sides of the rough opening. See Figure Do not stretch the flashing while applying it. When the flashing is in the proper position, apply firm pressure to the flashing working from the center to the corners and up the jamb to remove air bubbles. Secure the outer edges of the flashing with plastic cap nails.

18. Rough window openings should be flashed with building paper before the window frame is installed.
Building paper may also be used as a weather barrier. When using building paper around window openings, a sill pan is created by cutting a piece of the paper and folding it to fit the corner of the rough opening. See Figure The corner piece is stapled along the front edge of the rough opening. Another piece of building paper is slid into position over the corner piece and fastened along the side jamb using staples.

19. Windows must be properly sealed to prevent air and moisture infiltration.
When the window units are ready to be installed, a 1/4² to 3/8² bead of sealant must be applied to the housewrap along the top and sides of the rough opening. See Figure Do not apply sealant along the bottom of the rough opening. The window unit can then be installed per the manufacturer instructions. If a drip cap is required, the drip cap should be installed and properly sealed.

20. Window units are installed in the rough opening, which has been flashed with building paper. Some manufacturers recommend that the sash be removed before installation.
Some manufacturers recommend that the window sash be removed before setting the frame to avoid damaging the sash. Others suggest that the sash not be removed, enabling faster installation of the unit. Figure 56‑19 describes one method of installing traditional window units.

21. When replacing a wood window unit with a metal unit, the sashes, stops, and parting strips are removed. The metal unit is designed to fit into the existing wood frame in the building.
Another type of metal unit is designed to fit into an existing wood frame. These units are often used to replace worn wood sashes in older homes. These metal units are attached by driving screws through holes provided in the nailing flange and into the wood frame. See Figure 56‑20.

22. Skylights are installed in flat or pitched roofs.
Most skylights are made of clear or translucent plastic, which is secured in aluminum or wood frames. Insulating glass may also be used for skylights. Skylights are usually set on curbs constructed over the roof opening. See Figure 56‑21.

23. Skylights provide additional light and may provide ventilation.
Skylights can be used instead of dormer windows in gambrel or steeply pitched gable roofs to provide ventilation and light. See Figure 56‑22.

24. Skylights may be installed over a light shaft in an attic roof
Skylights may be installed over a light shaft in an attic roof. The light shaft is framed between the ceiling joist and roof rafters and is surfaced with gypsum board or wood paneling.
Skylights can also be installed over a light shaft that extends through the attic. See Figure 56‑23.

25. Main entrance doors may be single or double doors
Main entrance doors may be single or double doors. Main entrance doors may be flanked by sidelights or a transom.
Exterior doors, also known as entry doors, provide passage between the inside and outside of a building. The main entrance door unit is usually at the front or street side of the building. Main entrance doors may be a single door, double doors, or a single door flanked by windows. See Figure Main entrance doors are made of solid wood, or fiberglass or steel with an insulated foam core. Many main entrance doors have a fixed window.

26. Exterior doors provide passage between the inside and outside of a building. Exterior doors may be flush, panel, or crossbuck doors, with or without lights.
Examples of exterior door styles are shown in Figure 56‑25.

27. Exterior glass sliding doors are frequently used for passage to porches, patios, and terraces.
Passage into a building is also provided by one or more rear entrance (service) doors. Sliding glass or inswing doors are often used for service doors leading to porches, patios, or terraces. See Figure 56‑26.

28. Door units are installed in the rough opening, which has been flashed with building paper.
Before a door frame is installed, the rough door opening should be flashed with building paper. A procedure for installing an exterior wood door frame is described in Figure 56‑27.

29. Metal doorjambs are anchored to a masonry wall
Metal doorjambs are anchored to a masonry wall. One end of the anchors is welded to the doorjamb and the other end is embedded between the masonry courses.
Wood or metal frames are plumbed, aligned, and securely braced according to dimensions on the prints. The masonry walls are then built up on both sides and the doorjamb is anchored at the masonry joints. See Figure 56‑28.

30. When installing wood frames in exterior masonry walls, the frames must be accurately plumbed, leveled, and braced. Masonry walls are then constructed on both sides.
The procedure for installing a wood door frame in masonry walls is shown in Figure 56‑29.

31. Sliding glass doors may be two- or three-door configurations
Sliding glass doors may be two- or three-door configurations. The two doors on the right of this sliding glass door unit slide while the door on the left is stationary.
Two- and three-door units are common sliding glass door configurations. In two‑door units, both doors may slide or one door may be stationary. In three‑door units, one or two of the doors may slide while the other door remains stationary. See Figure Sliding glass doors typically include double or triple glazing to provide proper insulation.

32. Overhead garage doors are the most common type of garage door.
Garage doors must be functional and attractive and must complement the building design. See Figure 56‑31. Overhead garage doors are the most common type of garage door. Older garage doors are hinged and open to the sides.

33. Sectional roll‑up garage doors are guided by a track system fastened to the jambs and suspended from the ceiling.
A sectional roll‑up door is more expensive and operates more efficiently than a one-piece swing­up door. A sectional roll-up door is constructed in sections that are hinged together. Door movement is controlled by a track system fastened to the side jambs and suspended from the ceiling of the garage. See Figure 56‑32.

34. Steel overhead rolling doors are used in industrial and commercial buildings.
A rolling steel door is normally used in industrial and commercial buildings. See Figure 56‑33. The door rolls up into a housing unit located over the garage door and does not require attachment to the ceiling, thus saving overhead space.

35. Automatic opening systems are widely used with residential overhead garage doors. The system shown here has a chain‑and‑cable mechanism operated by an electric motor, which is activated by a pushbutton in the garage or a transmitter carried in an automobile.
For convenience and security, overhead doors may be equipped with automatic opening systems. See Figure 56‑34. An electric motor operates chains or cables that lift and lower the door. The electric motor is activated by a radio‑controlled unit inside the car or by a switch located in the garage.

36. Rough openings for overhead garage doors must accommodate space needed for the garage door in the open position.
The rough opening for an overhead garage door must be constructed to the correct dimensions to avoid installation problems. Correct layout for a rough opening is based on the garage door size, jamb thickness, and required clearances. See Figure 56‑35.

37. Various hardware components are used for an overhead garage door.
Manufacturer instructions for installing overhead garage door hardware should be carefully followed. Typical hardware is shown in Figure 56‑36. Angled tracks provide a weathertight seal for a garage door. Torsion springs allow the door to open and close smoothly. An extension spring counterbalance device incorporates a safety cable for use in the event of a broken spring. Other hardware includes heavy-duty rollers, hinges, a bell crank door latch, and reinforcing steel struts.