How to Cut Vinyl Window Grid Inserts to Size

Window grid inserts give single-pane windows a multi-pane finish.  Vinyl grid inserts come from the manufacturer in over-sized sections.

A window-grid insert installer custom cuts the vinyl grid to fit the window's opening.  Windows with a beveled sash use window grinds with angled cuts and a straight-cut window grid fits in a window sash with a flat opening.

After cutting the vinyl window-grid insert, the installer mounts the grid to the window with either mounting clips or an adhesive. 

1. Measure the window sash's opening with a tape measure. If the window uses a beveled opening, measure the window's smaller daylight opening and the larger sash opening. The daylight opening touches the window pane.
2. Arrange cuts on the vinyl window-grid insert, using a pencil to place measurement marks on the grid's surface. If the window uses a sash with a flat opening, place the measurement marks on the vinyl grid's exterior side. If the window uses a beveled sash, place the sash measurement on the grid's exterior side and the window's daylight opening on the grid's interior side.
3. Cut through the vinyl window-grid inserts along its sash-opening measurement marks, using a 4-inch angle grinder equipped with a 4-inch fine-tooth wood blade. Hold the center of the blade on the measurement marks. An angle grinder's high-speed rotation combined with the fine-tooth blade leaves smooth, chip-free cuts along the grid's edges.
4. Cut the beveled edge of the vinyl window-grid insert, using the angle grinder's blade to custom cut the bevel's angle. The bevel's angle depends on the window manufacturer's sash design.
5. Test fit each vinyl window-grid insert in its respective window. The grid should slip in the window sash's opening without binding. Trim the grid as needed.

Tip

If the vinyl window-grid insert has a gap between one of its edges and the window sash, center the grid over the window pane and fill the equally sized gaps on both sides of the grid with a latex caulk.