Repairing Window Shades

A window shade (right) has a hollow roller with a coiled spring inside. Drawing down the shade puts tension on the spring; a ratchet and flat pin at one end hold this tension until you release it. A stationary pin at the other end turns freely in its bracket.

Tools: Framing square, scissors or utility knife, staple gun, and saw.

Troubleshooting Window Shades




Goes up with a bang

Too much tension on the spring

Take down the shade, unroll a few inches, and replace it in its bracket

Goes up too slowly

Not enough tension on the spring

Increase tension by rerolling

Will not catch

Bent or worn brackets; ratchet not holding

Align brackets; if ratchet is bad, replace roller


Not enough clearance from brackets

Bend brackets apart or shorten stationary pin

Measure shade material. If you take down an old shade and unroll it, you will see that its shade material has been stapled to the roller. Take off the old material. Then square off the edge of the new material. Carefully align this edge with the guideline on the roller before you drive in the new staples.

Cut roller. Remove the material, saw the roller to length with a fine-toothed saw, reinsert the stationary pin, cut the material to size, and replace it.

Measure for inside or outside mount. For inside mounting, measure from jamb to jamb and subtract 1/8 inch for clearance. Measure for length and add 1 1/2 inches. For outside mounting, the width should be at least 1 1/2 inches larger than the opening. The length should be 1 1/2 inches longer than the span from the top of the upper trim to the sill.

Repairing Venetian Blinds

Inside the head box of a Venetian blind, a tilt tube supports a pair of tape ladders on which the blind’s slats rest. To open or close the slats, pull one end of a tilt cord wrapped around the pulley of a worm gear. This gear rotates the tube and changes the pitch of the slats. A lift cord, strung over a series of pulleys and down through the slats to the base piece, raises and lowers the entire slat assembly. When the tilting mechanism balks, look for cord threads or dirt in the worm gear. If the blind refuses to go up or down, the lift cord has either broken, frayed, or jammed. If so replace both cords and check the tape ladders as well.

Tools: Screwdriver, utility knife, and staple gun.

1. Disassemble the blind. Remove any clamps at the bottom of the base. On wood blinds the tapes are stapled. Snip off the lift cord at either side and remove by pulling as if raising the blind. Slide out the slats. In the head box, free the tapes by removing the clips holding the tapes to the tilt tube.

2. Thread lift cords. Attach the new tapes to the tilt tube and the base piece, then extend the ladders and slide the slats into place. Thread the lift cords from the base piece on each side up, over the pulleys, and back down through the lift lock.

3. Thread tilt cord. Note that the ladders’ rungs are offset from each other. Weave the lift cord on alternate sides of the rungs. Snip any tassels from the old tilt cord, thread the new cord over the worm gear pulley, and replace the tassels.

Installing Interior Storm Sashes

Fitting a storm sash on the inner side of an existing window cuts heat loss in half without the expense of buying exterior storm windows. You can install kit sashes, or make your own from 1/8 inch acrylic held in place with wood picture-frame molding. Fasten acrylic to window casings with screws and then apply self-adhesive weather stripping around the edges so you can remove the pane easily.

Tools: Tape measure, framing square, utility knife, sanding block, and hacksaw.

1. Measure the window. Measure to the outside of casings. Test-fit a piece of acrylic into the trim pieces (see below), then subtract enough to allow for the self-adhesive trim at the sides, top, and sill. Measure and mark a piece of acrylic with a knife at the beginning and end of each cut.

2. Trim the acrylic. Lay the acrylic piece on a flat surface, protective film-side down. Hold a framing square or drywall square firmly in place and draw a utility knife along the straightedge several times. Place the score on a table edge and push down on both sides to snap the cut. Smooth rough edges with a sanding block.

3. Cut the sill. When you measure for cutting the sill trim, be sure to allow for the strips at the sides. Hold the sill trim firmly in place and cut with a hacksaw. Cut slowly so you do not bend the trim. Snap the sill piece onto the bottom of the pane.

4. Apply self-adhesive trim. Most side and top trims snap open and have adhesive backings. Cut them to fit using a hacksaw. Snap the pieces onto the perimeter of the pane. After assembly, lift the unit into place and check that it fits; you may need to recut a piece.

5. Use joiner strips for large windows. Special joiner strips splice together more than one acrylic sheet for large windows or patio doors. Snap the flexible strips onto a sheet so the joiner strips will fit together as shown, then add the second sheet.

6. Install the sash. Secure the sill trim. To attach the side and top pieces, remove the adhesive backing’s protective paper and press only when you are sure the position is correct; if you reposition it, the adhesive will not be as strong. Make sure there are no air gaps.

7. Remove the pane for cleaning. To remove the pane for cleaning or ventilation, snap open the side and top trim and lift out the acrylic.

Working with and Maintaining Acrylic - Acrylic is in some ways easier to work with than glass. You can drill holes through it, and it’s much easier to trim off a small amount. However acrylic scratches easily. Don’t remove the protective film until the pane is completely installed. Wash acrylic with mild liquid detergent and lots of water or a manufacturer-specified cleaner. If an inside sash collects condensed water when the weather is cold, remove the pane and dry both the pane and the window.

Using Window Treatments in Cold Climates

On average, windows comprise only 10 percent of the wall area of a house. Yet they account for as much as 40 percent of a house’s heat loss. R-value measures resistance to heat flow. To determine your window’s total R-value, add up the R-values of all your window’s features using the chart at right. A home energy audit—free from many gas and electric utility companies and many state energy agencies—shows you the savings and payback period for new items.

Effective window treatment involves more than simply hanging drapes. The temperature difference between indoors and outdoors creates a convection current between the glass and the insulation. This causes the cold air generated in the airspace to flow out at the bottom, reducing the R-value of the treatment. In addition moisture in the air condenses on the cold glass. The condensate may run down onto the sill right away, or it may accumulate as frost to later melt and run down. Either way the condensate may damage the sill.

Window Treatment R-Values





Double-glazed (DG)


Low-E glass


Interior storm sash


Exterior storm/screen


Quilted shade


How condensation occurs. The key to window insulation is a vapor-impervious construction and tight air seals at the sides and bottom. If a storm window—either interior or exterior—is not well sealed, the mix of cold and warm air will create vapor that collects on the windowpane.

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