Friday, February 8, 2008

Rebuild, Don't Replace Old Windows

Old worn out double hung windows are the largest source of drafts and energy loss in a house. You can replace a window for about $250 or rebuild it with new tracks at a fraction of the cost.

Years of opening and closing a window, the settling of the house and the effects of weather take their toll on a window. When it shows signs of wear and rattles in the wind it's time to take steps to rebuild it, an inexpensive alternative to a complete replacement. For less than $50 a window and a few hours of work you can repair an old double hung windows if the sashes are still in good shape.

Jamb liner kits of either vinyl or aluminum and stainless provide new fully weatherstripped channels for old sashes to ride in. These replacement jambs teamed with a quality exterior storm window have the same efficiency as many double glazed replacement window.

Both the vinyl and aluminum and stainless replacement channels are basically the same. The slots in the old jamb that the window sashes ride in eventually wear and the window loosens in the jamb. The sashes also lose alignment and large cracks develop at the center meeting rail allowing air to leak between the jamb and sash and between the inner and outer sash. The new replacement jambs have weatherstripped tracks that fit the old window sashes snugly so friction holds them open which eliminates the need for sash weights. This allows you to fill the sash weight compartments with insulation and stop another major source of air infiltration.

Rebuilding a window with either the vinyl or aluminum and stainless channels is the same. The vinyl channels are easier to cut to fit an odd sized window and are available in long lengths to fit oversized custom built windows. The aluminum and stainless channels offer the option of a take out jamb that allows the removal of both the inner and outer sashes for easy access for cleaning.

Measuring

The jamb liner must be at least as long as the existing window jamb is high. The aluminum and stainless jamb liner kit sold by Quaker suggests that you measure the glass area of your window and then consult their chart on the package to determine the size of the liner to purchase. This works for most windows. If you have a non-standard site built window or one with different-sized sashes measure the distance inside the window channel between the bottom of the sash (not the window sill) and the top of the sash. Purchase a jamb liner kit that is at least as long or longer than this measurement.

Preparing the Jamb

The inside stop, inside sash, parting stop and outside sash are removed in that order. You will reinstall the inside stop and both sashes so work on them carefully.

Use a stiff putty knife or small pry bar to remove the inner stop. Push the blade between the stop and jamb and gently pry up. If the stop is covered with many coats of paint try to drive a putty knife between the stop and window jamb from the window track side of the stop. Be careful, if the sash weight cords are broken or the window is very worn, the window sash can fall out of the jamb when you remove one of the stops. Remove the window and set it aside in a safe place.

The outer sash is held in place by the parting stop in the center of the window jamb. This piece of molding is usually set into a groove milled in the sash. If the outside window sash is not painted shut you may be able to remove it by prying it out of the groove. Don't worry about breaking this piece of molding, because it gets discarded. You can also chisel the parting stop flush with the jams. You don't have to remove it from the slot, just knock off the protrusion so the outside sash can be removed. Remove one stop and pull that side of the sash toward you to remove it. If the window won't budge it's probably because it's painted in place. In that case you must break the bond between the paint and window from the outside. Be careful that the window does not fall out as you try to loosen it.

When both window sashes are out remove the sash weight pulleys which are located at the top of the jamb. Most are screwed in place but yours might be nailed in place. Remove the screws or pry out the pulleys.

Lift out the access doors to the weight compartment which is located in the lower section of each side of the jamb. Some are held in place with a screw, others with nails.

Remove the old weights and fill this cavity with insulation. The easiest way is to pull apart a piece of fiberglass insulation and push small pieces of it into the cavity with a small stick or piece of dowel. Wear a long sleeved shirt, hat, gloves and a dust mask when you're working with any insulation product. Pack the insulation in tight. Your primary goal is to stop air infiltration through the opening. When the weight pockets are full, reinstall the access doors.

The face of the jam must be level and free of protrusions so the replacement liners can lay flat against the jamb. Scrape away any old paint, weatherstripping or anything else that interferes with the new liners.

The liners must be cut to fit into the jamb. Their bottoms are cut at an angle to match the slope of the sill. The angle at the bottom makes the jamb liners either right or left sides, make sure you cut off the square end and check that you are cutting the correct piece if the measurements of the sides of your jamb are different.

If the windows are very old the angle of the sill may not match the precut angle on the bottom of the sill liners. In this case copy the sill angle of your window and transfer it to the bottom of the jamb liner with a adjustable bevel, then recut the bottom of the liner to match your window.

The top parting stop must be notched at the jamb about 1/2-in. to clear the parting stop on the new jamb liner. Measure the exact height of the center parting stop and weatherstripping of the new liner. Then measure from the jamb toward the center of the window and mark the stop. Cut through the stop with a hand saw and knock out the small piece with a hammer or chisel.

Put the two sides of the liner in place and check their fit. They should not be too tight. This is especially important for the vinyl jamb liner because it may bow out away from the jamb and make the window difficult to operate. Don't secure the jamb liners yet. First the window sashes must be inserted into them before they are permanently installed.

Preparing the Sashes

Remove the window weight cords for the sashes if they have not fallen off. Some are nailed in place others are held in place by a tight fitting knot pushed into a slot.

Scrape off all old paint from the sides of the sashes especially in the area that will be in the jamb liner track. Since the sash is out of the window and easy to work on, it's a good time to replace any broken glass, repair the putty and paint the sash if necessary.

Place the sashes in the jamb liners and check the fit. If there is a buildup of paint on the sashes the fit will probably be very tight. Sand the sides of the sashes until they fit snugly into the jamb liner.

Check the fit of the inside and outside sash at the meeting rails. In most cases the weatherstripping will seal the gap around the parting stop but the new jamb liner many have a smaller parting stop than the original window. This may cause a gap around the parting stop that weatherstripping doesn't fill. If that's the case glue a small block of wood in the area and notch the meeting rails to fit the new parting stop.

Prime and paint all exposed wood before you reinstall the sashes. If you're in a hurry seal the bare wood with a fast drying shellac or pigmented shellac primer like BIN (tm).

Installing the Jamb Liners

To install the new liners first lubricate the edges of the jamb weatherstripping with the silicone lubricant provided with the kit. Next place the windows in the jamb liners and check that the angled bottom of the liners are facing down. Slide the windows together to the center of the jamb liner then place the bottom of the liner into the old jamb.

Raise the jamb liners and windows up so the pointed end of the liners are as far forward as possible in the old jamb and resting against the outer stop. Continue raising and pushing the liners and window sashes into the old jamb. When fully upright temporarily secure the top of the jam liners with a nail or screw but don't drive the fastener home.

Slide the windows up and down and check their fit in the jamb. They may be difficult to move at first but the jambs will loosen after some use. If everything checks out fasten the jamb liners to the old jambs with a nail or screw driven through the top of the jamb. The inside stop holds the jamb in place so these fasteners are needed only until you install this stop.

Weatherstripping the Sashes

V-type vinyl self adhesive weatherstripping is the easiest to apply and does a good job of sealing up the window. The spring brass version of this type weatherstripping is more durable but it's harder to install. In either case apply the weatherstripping to the upper edge of the outside sash with the point of the V facing in. Then apply a strip to the back edge of the meeting rail of the outside sash. Keep the point of the V facing up. Lastly apply weatherstripping to the bottom of the inner sash with the point of the V facing in.

Trimming Out the Window

Before you install the inner stop run a light bead of a latex silicone caulk along the joint between the jamb liner and old jamb. Also caulk the joints between the liner and jamb at the top and bottom. Fill any gap between new parting stop of the liner and the old top stop with caulk. Wipe up any excess caulk with a damp rag before it has a chance to set up.

Reinstall the inner stop. Use longer nails or reposition the nails so they will hold the stop firmly in place. Then recheck the window movement.

2 comments:

Russell said...

Where can replacement jamb liners be purchased?

Anonymous said...

Please help with some sources for these parts!