MAKING AN OUTLET-BOX CUTOUT

Precise cutouts are sometimes required for certain situations, such as fitting siding panels over vents or electrical outlet boxes. Careful layout is the key here.

1. Place the siding panel directly below where it will be in­stalled. Mark where the sides of the box hit the panel.

2. Reposition the panel to one side of the box, clipping it into the panel just below the box. Mark where the top and bottom of the box hit the panel.

3. Outline the cutout where the horizontal and vertical lines intersect, then cut the opening with a sharp utility knife.

more than 1 in. to fit, you must fur out or shim the undersill trim. The deeper the notch in the siding, the thicker the shim you’ll need. By fur­ring out the undersill trim, you can prevent the surface of the siding from bowing in beneath the window. Try not to have any joints between panels located beneath or above windows.

To determine a notch’s location horizontally in the panel beneath a window, measure from the last piece of siding to the opening and mark it on the panel (don’t forget to add 1 in. for the overlap). For an accurate height measurement vertically, lock a scrap of siding into the nail flange of the piece below, then slide the scrap against the window edge. Mark where the scrap hits the bottom of the window and transfer the mark to the panel you’re cutting. Finally, measure the length of the opening and transfer it to the siding, leaving /4 in. on each side for ex­pansion. These notched cuts can be made with a utility knife, a hacksaw, or tinsnips. Use a snap-lock punch to create crimps, or tabs, /4 in. down from the top edge of the notched siding and make crimps every 6 in. across the length of the window. The crimps must face out to lock into the undersill trim.

The panels that fit over the tops of windows and doors are marked and notched in the same way as those on the bottom. The horizontal part of the siding slips down into the J-channel. To make cutouts where the siding fits over a dryer vent, an electrical outlet box, or another protru­sion, use the techniques discussed here and on the facing page.