Putting in a Window

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With prefabricated window units, fitting a window into a rough opening is a simple carpentry job. Made of wood, vinyl, or vinyl- or aluminum-clad wood, these units come fully assembled, some with exterior trim already attached. A double-hung window is illustrated here, but other styles—single-hung, casement, stationary, and horizontal sliding windows, for example—are also available. Choose a style and material that blends with your existing windows.

Buying the Right Unit: For a house with siding or stucco that has walls constructed of 2-by-4s, get a window that fits the opening in height, width, and thickness. If the walls are thicker than the standard, such as those constructed of 2-by-6s, you will need to order jamb extensions with the window unit, or you can make them yourself. For a house with masonry walls, the window exterior will be recessed, with its inside edges flush with the interior walls.

When purchasing a wood window, be careful not to buy the type—meant for new construction—that has nailing flanges projecting from the jamb. These flanges must be tucked between the exterior siding and sheathing, making it necessary for you to remove siding all around the opening before you install the window and to replace it afterward.

The upper, exterior sash of this window slides down, and the lower, interior sash slides up in channels mounted on the side jambs. Some windows use springs and balances to keep the sashes in place, but most now have channels made of compression weather stripping, which maintains pressure on the sashes to hold them open in any position; these flexible-vinyl channels can be pushed inward toward the frame, freeing the sash and allowing it to be tilted forward for cleaning. Exterior casing—or brickmold—covers the outside edges of the top and side jambs. The exterior sill slopes outward to lead rain away from the bottom of the window.

SAFETY FIRST: When hammering, wear goggles as protection against flying nails.

TOOLS:

  • Carpenter’s level
  • Hammer
  • Caulking gun
  • Miter box and backsaw
  • Nail set

 

MATERIALS:

  • Prefabricated wood window
  • Flashing
  • Felt weather stripping
  • Jamb extensions (0.75” stock)
  • Wood glue
  • Finishing nails (2.5”)
  • Wood shims
  • Fiberglass insulation strips
  • Caulk
  • Window stool stock
  • Window casing stock
  • Wood putty

A WINDOW MADE OF WOOD

103 EXTERIOR TOP CASING; EXTERIOR; SIDE CASING; SASH CHANNEL; EXTERIOR SILL

Anatomy of a double-hung wood window.

1. Tipping in the window.

• For a house with wood or aluminum siding or a stucco exterior, install flashing over the window opening.

• Push felt weather stripping into the gaps between the siding and the sheathing.

• Set the window unit in the opening, pushing it up under the flashing, then shove the window back so the exterior casing fits firmly against the sheathing.

For a house with a masonry exterior, flashing is not necessary because the masonry will overhang the window. Set the unit in the opening and push it back to fit against the rough frame.

2. Extending the jamb.

When the interior jamb of the window is not flush with the wall-finishing material you plan to use, you must make up the distance with jamb extensions.

• If you ordered a window with jamb extensions, use those; if not, cut 0.75” stock into four strips of the thickness and lengths required.

• Glue the strips to the interior edges of the jamb and secure them with 2.5” finishing nails.

3. Leveling and plumbing the window.

• Working outside the house, center the window between the jack studs.

• Lift the unit until the top jamb butts against the bottom of the header.

• Use a carpenter’s level to determine which side of the window is lower, then nail the lower top corner to the header with a 2.5” finishing nail.

• Lower the other top corner until the window is level, and nail that corner in place.

• Inside the house, check the level, then wedge shims between the bottom of the window and the rough sill.

• Plumb the window from front to back—inserting at least two shims on each side—and fill gaps around it with strips of fiberglass insulation.

• Nail through all the shims into the frame.

• Finally, secure and caulk the exterior casing.

104

4. Attaching the interior stool.

• Finish the interior wall, butting the wail material against the window jamb.

• If you do not want an interior sill—called a stool—continue on to Step 5 and install casing around all four sides of the window.

• To make an interior stool, cut stool stock long enough to cover the front of the frame and extend on each side at least to the width of the casing you plan to use.

• Notch the back of the stool at both ends so the center section will fit between the side jambs. If you wish to round off the outer edge, use a wood file and sandpaper.

• Set the stool in place and anchor it to the bottom of the window frame with finishing nails.

• Cut casing or apron molding 1 inch shorter than the stool to cover the joint under the stool, rounding the bottom edge, if you wish.

• Nail the apron to the studs below the window.

5. Adding interior casing.

• Measure the lengths of the side and top jambs. If you are adding casing to the bottom, rather than a stool, mea sure the bottom jamb also.

• Follow the directions, Steps 3 and 4, to miter, cut, and attach the casing.

• Countersink all interior trim nails with a nail set. Fill the holes with wood putty.

105c LOW-MAINTENANCE VINYL WINDOW

An alternative to a wood window is one made of vinyl, which never needs painting As with wood windows, the single- and double hung styles generally have tilt-out sashes for easy cleaning. Since most vinyl windows do not come with exterior casing attached, choose a type that has optional vinyl brickmold that affixes to the exterior frame. The vinyl window should have a nailing flange that attaches to the rough opening frame. Cover the flange with asphalt building paper tucked under the siding before you secure the brickmold. On the interior, add jamb extensions, stool, and casing (Steps 2-5); or, if you will be installing wall board, forgo the casing and extend the wallboard to cover the rough opening frame right up to the vinyl.

















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Updated: Tuesday, September 6, 2011 12:09