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Skylight Installation: A Step By Step Guide For Homeowners

June 9th, 2021 BY First American Roofing

How cool would it be to install a new skylight in your home? You get more natural light, some more fresh air, and they just look plain cool. Skylight installation might sound really complicated, but it can be done in a few steps and with the help of a professional. We’re going to give you a step-by-step guide on how to install a skylight on your roof in just one day.

What You’ll Need to Install Your Skylight

STEP 1: CUT THE ROOF OPENING

man cutting an opening in a roof for skylight

The first step will, of course, be to cut the opening to install your skylight. First, you’ll want to ensure you’ve got good weather for the day. The last thing you want to happen is for rain or wind to ruin this step. Then, from below where you want the skylight, drill four long deck screws through where each corner will be. Those screws will indicate on the roof where to begin.

First, remove all the shingles at least 6 inches past each of those screw markers. Then, mark four straight chalk lines as a guide to using the circular saw to cut out the rectangle shape in the roof.

STEP 2: INSTALL THE FLASHING

Next, install your flashing along the entire window sill. This creates the first barrier to prevent leaks. The self-adhesive flashing should go on each side, then cut to fold over the edge enough to create a barrier the width of the skylight sill. Nail the sheathing down on all sides using your roofing nailer.

STEP 3: PLACE THE SKYLIGHT

Once the sill has flashing securely installed, carefully get your skylight to the roof with the help of a friend or pully system. Place it in the cut-out gently in place. The skylight should have a flange edge where you can place your 1.25-inch roofing nails every few inches to secure it in place.

STEP 4: SEAL THE EDGES

Time for more sealing. Cut your self-adhesive membrane to stick to the skylight’s flange and extend past its edge a few inches. This creates a watertight seal around every edge of your skylight. You will need to do this on every side, and this is the next barrier against leaks before you install your sill and step flashing.

STEP 5: INSTALL SILL FLASHING

Your skylight came with a u-shaped piece of flashing to place on the bottom sill. This should easily slide in place, and you can secure every side using your roofing nailer. Then, the final step will be to install your shingles back in place, covering that sill flashing. Note, this is only installed on the bottom of your skylight window.

STEP 6: INSTALL STEP FLASHING

Next, each side requires step flashing to be installed. This installation will go in steps, from the bottom up. Place your first l-shaped step flashing piece near the bottom of the skylight. Nail it in place and then cover it with a shingle. Then, install your next step flashing overlapping that shingle by a few inches, secure it in place, and put your next shingle in its proper place. Continue these steps on both sides until you reach the top corners.

STEP 7: COUNTERFLASHING

The counterflashing will simply click into place over where you installed your step flashing on each side. This is a key step to ensuring snow and rain don’t blow under the edge of your skylight.

STEP 8: SADDLE FLASHING

man installing a skylight into a roof

The saddle flashing is similar to the sill flashing, but it goes on the top. You will simply slide it under the shingles above your skylight and slide it in place on top. Secure it with roofing nails and re-install your shingles over the saddle flashing as you’ve done thus far, and it should be good to go.

STEP 9: ENJOY!

With all of the flashing, shingles, and skylight in place, safely make your way back down off the roof and head inside. You can double-check that everything looks good from the inside, and if you have a skylight that opens, you can test that and make sure everything is in working order.

These steps we’ve laid out are relatively simple but do require a certain amount of expertise. We always recommend hiring a professional when you are doing anything that requires getting up on the roof and making drastic home improvements like cutting the opening in the roof. One slip from an inexperienced homeowner can cause injury, accidents, or damage to your home. Luckily, First American Roofing offers both skylight and sun tunnel installation, so you don’t have to worry about a thing!