Install New Construction Windows

Window Liquidators sells vinyl replacement and new construction windows for you to install or have installed by a professional.

Installing new construction windows is easy, even for someone who is new to DIY windows. These step-by-step instructions show you how.

Get more information on measuring your windows before you buy. If you’re uncertain about size, or whether to replace your window frame before buying, our friendly staff can help.

Take the worry out of measuring with our measuring guarantee.

Call us at 855-892-0543 or email us at sales@windowliquidators.com.

Before You Start

Read these instructions carefully and identify all the parts and tools used 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.

Tools You’ll Need

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

  • tape measure
  • razor knife
  • caulking gun
  • caulk
  • flathead Screwdriver
  • Phillips head screwdriver
  • flat bar
  • pry bar
  • 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. Please call us to order at 866-589-9367.

Step-by-Step Installation Instructions

Step 1: Measure the Window Opening

The rough opening must be plum, level, square and ½-inch larger than the window size in width and height, not including the nailing fins (See fig. 1).

Close and lock the sash (the frame that holds the glass) to keep the window square during installation.

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. (See fig. 3)

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: Caulk the Window

Apply a 3/8-inch continuous bead of silicone caulking to the interior surface of the nailing fin, covering the holes in the fin, to seal the window's fin to the sheathing or house wrap.

If the rough opening is larger than the window by more than ½-inch, also apply the caulk to the sheathing or house wrap, making sure the bead is no more than ¼-inch from the edge of the rough opening. It should be covered by the nailing fin when the window is installed.

Step 4: Set the Shims

To keep the window straight and level, install shims at all locations where the jamb, intermediate jamb, or the stiles of a slider meet the sill. (See fig. 2A & 2B)

Evenly place ¼-inch shims on the sill plate of the window opening. Double or triple windows should have a shim under each mullion (the vertical bars between the panes of glass), intermediate jamb or the center stiles of sliders. (See fig. 2A & 2B)

Step 5: Set the Window

Set the window on the shims and adjust the side clearance to be equal on both sides. Tack one upper corner of the nailing fin to keep the window in place. Check the sill with a level and adjust the shims as required to level the sill. Re-adjust the side clearance if necessary.

Shims must be cut to exact thickness to fit snug and not fall out. Do not force the shims into place, because this can push the sill out of level. Shim both sides of the window as needed to assure the window is plumb and the margins are equal. (see fig. 2A & 2B)

Measure the window diagonally, from bottom left corner to top right corner and from bottom right corner to top left corner to ensure it is square.

When the above is done correctly the width across the top, middle and bottom of the window will measure the same. The wool pile clearance between the sash stile and jamb mainframe should be equal. The meeting rail and lock rail should align evenly, with parallel sight lines. The window locks should engage smoothly.

Step 6: Nail the Window Fins

Use stainless or galvanized steel roofing nails, a minimum of one inch, or long enough to penetrate studs.

Nail the entire perimeter of the nailing fin to the sheathing, using every other slotted hole at a minimum on single windows. Nail double and triple windows in every slotted hole.

Nail the fin snug but do not "sink" the nails. Nailing should be just tight enough to hold the window but not stop the movement of the framework underneath during expansion and contraction. Make sure the head and sill are not crowned up or down, or the jambs bowed in or out.

Additional Tips

  • 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.