How to Install Vinyl Replacement Windows

Installing your new vinyl replacement windows is easy – even for someone who is new to DIY windows. These step-by-step instructions and videos show you how.

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Before You Start Installing Your Windows

Read these instructions carefully and identify all the parts and tools you’ll need during the installation.Most work can be done from inside the house. Double check the opening and your new window size to be sure it will fit before removing the old window components.

Some windows are shipped with bands around the middle of the window or have some other way to keep the unit square. Do not remove these until the unit is in the opening is secure.

Before You Start Installing Your Windows

Today’s vinyl replacement windows need only simple hand tools for installation. You’ll need:

  • Tape measure
  • Utility knife
  • Caulking gun
  • Caulk
  • Flathead screwdriver
  • Phillips head screwdriver
  • Flat bar
  • Pry bar
  • Chisel
  • Level
  • Square
  • Hammer
  • Drill

Choosing Your Caulk

The caulk you use is important. For interior use, if you are going to paint, choose an acrylic-based sealant.

Exterior caulk should be a high-performance elastomeric polymer sealant that closely matches the color of the window. We offer OSI Quad exterior window caulk, which matches the above criteria.

Step-by-Step Installation Instructions

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 in accordance with ASTM-D779.
Sill flashing should already be applied before window installation and it 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 the head flashing similarly, extending two inches past either side of the jamb flashing, to complete the window flashing detail.
Install batt insulation between the window and rough opening. It is very important that these openings are not over-stuffed because they can warp the frame. Do NOT use expanding foam. Doing so will void warranties.

Step 3: Remove the Old Window

  1. Remove inside stops with a flat bar and save them for later, being careful not to break them.
  2. Remove existing cords, weights, spring balances or pulleys.
  3. Pry out the top parting stop (the narrow strip separating the sashes in the window frame). Pliers can usually remove most stops, but if not, use the flat-head screwdriver to pry the stop loose.
  4. Pry out the side parting stops (on older wooden windows, the piece of trim attached to each side jamb). For stops that are heavily painted or stuck, use the chisel to shear off the part of the stop that protrudes in the jamb.
  5. Once the parting stops are out, the upper sash can be easily removed from the outer track.
  6. If the old window has a pre-formed aluminum track, there will be no wood parting stop on the sides, but there will be one on the top. Remove the top parting stop then remove the staples holding the track.
  7. Remove the small aluminum block on the top and bottom of the aluminum track.

Step 4: Prepare the Opening

  1. 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 the old weights and cords, fill the holes with fiberglass insulation and cover them.
  2. Install a wood extender, aluminum capping or caulk on the outer sill frame of the replacement window .
  3. Caulk the inside edge of the blind stop along the top and down both sides. Make the caulk bead about 1/8-inch. The bead should not lie against the window frame, just the blind stop. Place a bead of caulk on the top of the expander.
  4. Lay fiberglass insulation on the sill.

Install the Replacement Window

  1. 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.
  2. 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.
  3. Place the shims behind the mounting screw holes. You will need to pre-drill two screw holes on each side at the top and bottom. The bottom screws will need to be recessed so they so not obstruct the movement of the balancers. To do this , drill through the frame with a drill bit the same size as the head of the screw to be used. Make sure you only drill through the first layer of the vinyl frame. Then with a smaller drill bit, drill through the second layer of vinyl frame, centered in the larger hole previously drilled. Tighten the screws lightly. Use flat shims, not tapered shims. Tapered shims can twist the frame. NOTE: some windows have a jamb adjuster that eliminates the need for shims in the center window. Adjust slightly. Once the frame is anchored lightly, check plumb, level and square and tighten all the screws. Do not over tighten. Secure is sufficient. If you over tighten, the frame can twist and the window will not operate correctly.
  4. Push the head expander tight against the window. Caulk against the inside molding and window to seal any gap.
  5. Replacing inside molding tightly against the window. Caulk against the inside molding and window to seal any gap.
  6. Caulk outside where the sill angle meets the sill. Take care to seal any gap.
  7. Caulk outside where the window meets the blind stop.

Finish the Job Inside and Outside

To complete the installation and carefully seal against the weather, it is helpful to repair any damage to the outside of the house.

Fill any old storm window holes or screen holes with putty.

If you should damage the interior stops when you remove them, or if old curtain rod brackets have been damaged, it may be wise to replace them.

Most lumberyards have a selection of moldings that will match anything you might have.

Additional Tips

Today’s vinyl replacement windows need only simple hand tools for installation. They are:

  • Remove or cut ventilation holes in plastic shipping wrap if windows are not installed immediately.
  • Do not lay windows flat or store in the sun. The heat will shrink the plastic wrapping and warp the frame.
  • Do not caulk or plug weep holes.
  • Do not drill into or through the sill of the window.
  • Protect vinyl sill from traffic and damage.
  • Do not lift window by top of frame, only by jambs.
  • Protect the window during construction and plastering.

    If special applications are needed during the installation, please contact the manufacturer for instructions and approval.

    Please note: The manufacturer’s warranty can be voided if these instructions are not followed.