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Step-by-Step Guide

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.

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 and secure.

Tools You'll Need

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

Tape measureRazor knifeCaulking gunCaulkFlathead screwdriverPhillips head screwdriverFlat barPry barLevelSquareHammerDrill

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

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Step 01: Measure the Window Opening

The rough opening must be plumb, level, square and ½-inch larger than the window size in width and height, not including the nailing fins. Close and lock the sash to keep the window square during installation.

02

Step 02: Install the Flashing

Use self-adhesive flexible flashing a minimum of 4″ wide, approved for use on vinyl, wood and house wrap. This flashing must meet a minimum water resistance of 24 hours per ASTM-D779. Sill flashing should extend beyond the sides of the window nailing fin at least two inches. Apply jamb and head flashing similarly, extending two inches past each side.

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Step 03: 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 caulk to the sheathing, ensuring the bead is no more than ¼-inch from the edge of the rough opening.

04

Step 04: Set the Shims

To keep the window straight and level, install shims at all locations where the jamb, intermediate jamb, or stiles of a slider meet the sill. Evenly place ¼-inch shims on the sill plate. Double or triple windows should have a shim under each mullion, intermediate jamb, or center stiles of sliders.

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Step 05: 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 shims as required. Measure the window diagonally from corner to corner to ensure it is square.

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Step 06: 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 (single windows) or every hole (double/triple windows). Nail snug but do not "sink" the nails.

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, contact the manufacturer for instructions and approval.
Please note: The manufacturer's warranty can be voided if these instructions are not followed.

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