Credit: Velux
Proper flashing is key to customer satisfaction, since any leaks will affect interior finishes.
Credit: Velux Proper flashing is key to customer satisfaction, since any leaks will affect interior finishes.

Runnin' and gunnin' is usually the way things go on roof replacements. But for skylights, slow down, lay out, and dial in.

The reason — especially for new fenestration — is that skylights tie in to interior finishes and have a big impact on customer satisfaction. It's usually carpentry-oriented workers who best handle the framing, shaft, and trim details.

Talk first. A happy customer — and the story they tell — starts with a design meeting. Unless it's a basic remove-and-replace, lay out the location and shaft style with your customer. This is the success gateway, especially where the skylight integrates with living space (think finished third-floor bedroom rather than 40-foot foyer).

Explore. For new windows, locate the unit inside first. Mark corners and snap lines. Next, find the rafters using exploratory holes. If possible, tweak the skylight location to match the actual rafter location, minimizing framing and drywall work.

Punch. With your location set, drive screws through the sheathing and shingles at each corner. Leave as much drywall as possible to catch debris from the forthcoming roof cut-out. Some manufacturers suggest coordinating skylight bottoms with full shingle courses. If it works, this saves time roofing.

Cut it out. On the roof, pop lines between screws, then cut shingles and sheathing with a circular saw or shingle saw. Carefully remove roof decking and discard.

Back inside. Remove the drywall. Using a circular saw to start header cuts creates fast, square cut-lines. Finish off with a reciprocating saw. Cut and install framing as square as possible. Include joist hangers if required.

Flashing and shingling. Strip the skylight's factory-installed cladding as required. Tip: Stab small screws in a block of foam insulation, for storage — they're usually aluminum and don't stick to magnetic bit holders, so be careful when reinstalling them.

Flash the roof deck with peel-and-stick membrane, then weave shingles with base, step, and head flashing as you run shingles.

When replacing the manufacturer's flashings/cladding, re-them properly on the unit's rubber gaskets; gaskets can sometimes deform, decreasing performance and inviting a callback.

Customize. Details such as flared shafts and headers can test carpentry skills. But in the end, it's those details — not the flashing or shingles — that become the story your customer tells about their skylights, and your work.

Mark Clement is a freelance writer and former contractor based in Ambler, Pa.