Skylight services

The single most useful question to ask a contractor is which of those four jobs they are quoting. "Fix the skylight" can mean a $300 flashing repair or a $4,000 unit-plus-opening rebuild, and some companies will quote the expensive version for a problem the cheap version solves. Make them tell you what they found and why the smaller fix won't hold.

Skylights sit at the intersection of two trades. The unit is a window; the thing that keeps water out is roofing. Plenty of window companies will sell you a skylight and plenty of roofers will install one, but the person doing the work needs to be comfortable detailing a curb and step-flashing into your specific roof covering. Ask what roofs they've flashed this month.

Material costs vary a lot by type. Fixr puts skylight material alone at roughly $229–$417 for a tubular unit, $295–$537 for a fixed skylight and $574–$1,044 for a ventilating one, with labor around $119–$216 for a new install and $176–$320 for a replacement. Those are unit-and-labor numbers, not the whole project — framing, interior finishing and roof repair around the opening are extra.

This is roof work, at height, often on a slope. We do not suggest homeowners get on the roof to inspect, seal or repair a skylight. Falls from residential roofs are a leading cause of serious home-improvement injury, and a tube of caulk applied from a ladder is the most common way a small leak becomes a hidden rot problem.

How to choose

Make them name the job

New opening, replacement in existing opening, reflash, or hardware repair. The price difference between these is enormous and the words get used loosely.

Ask who flashes it

If the salesperson is a window company and the flashing is subcontracted to "a roofer we use," get that roofer's name and license before you sign.

Insist on a manufacturer flashing kit

Skylight makers sell flashing kits matched to the unit and to the roof covering. A skylight bedded in sealant instead of flashed is a leak on a timer.

Get the interior finish in writing

Cutting a new opening means a drywall shaft, corner bead, paint and sometimes moving a rafter. Some quotes stop at the roof deck and leave you a hole in the ceiling.

Don't accept caulk as a repair

Sealant over failed flashing buys a season at most, and it hides the water while the deck rots. If the fix is a tube of goo, it isn't a fix.