How to Install Vinyl Replacement Windows

Step 1: Remove Old Storms or Screens

When replacing an old window with a vinyl replacement window you will no longer need storm windows or separate screens. If there are screens or storms mounted outside the house, remove them first. This will allow you to thoroughly clean the opening and seal or paint any problem areas.

Step 2: Install the Flashing

Use self-adhesive flexible flashing a minimum of 4″ wide, which has a self-adhering surface on one side. It should be approved for use on vinyl, wood and other substances such as house wrap. This flashing material must meet a minimum water resistance of 24 hours per ASTM-D779.

• Sill flashing should already be applied before window installation and should extend beyond the sides of the window nailing fin at least two inches.
• Apply jamb flashing over the jamb-nailing fin, continuing over and beyond the sill flashing, two inches below.
• Apply head flashing extending two inches past either side of the jamb flashing.
• Install batt insulation between the window and rough opening — do NOT use expanding foam, as this will void warranties.

Step 3: Remove the Old Window

• Remove inside stops with a flat bar and save them for later, being careful not to break them.
• Remove existing cords, weights, spring balances or pulleys.
• Pry out the top parting stop (the narrow strip separating the sashes in the window frame).
• Pry out the side parting stops. For stops that are heavily painted or stuck, use the chisel.
• Once the parting stops are out, the upper sash can be easily removed from the outer track.
• If the old window has a pre-formed aluminum track, remove the top parting stop then remove the staples holding the track.

Step 4: Prepare the Opening

• Clean the opening of any debris. Cover any holes made by the weight pulley.
• Remove any old screen hooks or other screws or fasteners.
• If there are holes left by old weights and cords, fill the holes with fiberglass insulation and cover them.
• Install a wood extender, aluminum capping or caulk on the outer sill frame.
• Caulk the inside edge of the blind stop along the top and down both sides. Lay fiberglass insulation on the sill.

Step 5: Install the Replacement Window

• Place the window in the caulked opening by placing the inside lower edge on the outside sill tightly against the stool. Tilt the window into the opening.
• Check for plumb and level. It is important that the window remain square in the opening even if the opening itself is not square. Use flat shims to keep the window square.
• Pre-drill two screw holes on each side at the top and bottom. The bottom screws must be recessed so they do not obstruct the movement of the balancers.
• Tighten the screws lightly. Check plumb, level and square and tighten all screws. Do not over-tighten — secure is sufficient.
• Push the head expander tight against the window and caulk against the inside molding to seal any gap.

Step 6: Finish the Job Inside and Outside

• Caulk outside where the sill angle meets the sill. Take care to seal any gap.
• Caulk outside where the window meets the blind stop.
• Fill any old storm window holes or screen holes with putty.
• If you should damage the interior stops when you remove them, replace them. Most lumberyards have a selection of moldings that will match anything you might have.