How to Install a Skylight

Once the placement for the skylight has been determined, locate the rafters with a stud finder and mark the locations between the rafter base for the rough opening.

Once you've determined the placement for the skylight, locate the rafters with a stud finder and mark the locations between the rafter base for the rough opening.

Using the dimensions of the selected skylight, frame the rough opening for it. Once the rough opening for the skylight has been framed, drive a screw into each of the corners of the opening. Use a screw long enough to entirely penetrate the roof so that the outline of the frame can be easily found.

Remove all of the shingles inside of and 6 to 12 inches outside of the screws that are marking the skylight frame. Using a chalk line and the screws as a guide, snap a line to mark the opening for the skylight. Remove the screws once the outline has been made on the roof.

Using a circular saw and the outline as a guide, cut out the opening for the skylight. Be sure to secure the portion of the roof that's being cut out so that it doesn’t fall inside. Cut away the roofing underlayment 6 inches on all sides of the opening. This will provide space for the ice-and-water shield to adhere directly to the actual decking around the opening.

Remove the cladding from the skylight by pulling the sides and bottom away from the skylight. Now place the skylight over the opening and center it, using the notches on the skylight as a guide. Once the skylight is centered over the opening, nail it into place through the flange, using the provided nails.

Measure and cut the ice-and-water shield at least 6 inches from each corner of the skylight. Starting at the bottom of the skylight, install the ice-and-water shield. Make sure that the ice-and-water shield runs up the frame of the skylight. Cut a relief slit in the corners and wrap them round the side of the skylight and flat across the roof. Follow the same process to install the ice-and-water shield on the sides and then finish with the top.

Install the bottom row of shingles and then place the sill flashing at the bottom edge of the skylight, overlapping the bottom row of shingles. Secure this with roofing nails. Once the sill flashing has been secured, start interweaving step flashing and shingles all the way up on both sides, from the bottom to the top. If the final piece of step flashing is too long, cut it to fit.

If a solar-powered venting skylight has been installed, now is the time to connect the solar panel to the body of the skylight.

After the step flashing and the shingles have been installed all the way up both sides, replace the cladding around the body of the skylight.

With the cladding in place, install the saddle flashing around the top of the skylight. Be sure to fit this over the cladding. Interweave another piece of the ice-and-water shield under the cut piece of underlayment above and then place it over the top of the saddle flashing. Now finish shingling the rest of the roof above the skylight.