EXTERIOR
How to Estimate Skylight Installation
Contractor method for estimating skylight installation: size, type, flashing and roof pitch.
Skylight bids fail on flashing and roof pitch. The unit is a fixed price; the leak-proof installation is where experience — and the quote — show.
THE SHORT ANSWER
How do you estimate skylight installation?
Count and size the units, choose fixed vs venting, price the flashing kit separately, then factor roof pitch and framing. An installed skylight runs $800-$2,500 depending on size and type.
Count, size and type the skylights
Fixed skylights are the baseline; venting adds 20%, tubular drops to 60%. Size matters more than count — a 3×4 ft unit is nearly double a 2×2 ft unit. Note whether the ceiling is open or finished (a shaft adds cost).
Price flashing as its own line
The flashing kit is the difference between a dry ceiling and a call-back. Standard flashing ~$300 per unit, premium curb flashing more. On steep roofs, never skimp here.
Factor roof pitch and framing
Use 30% as an initial steep-roof planning factor, then replace it with the job's access and fall-protection cost. If the unit conflicts with rafters, price the required framing separately. Use the Skylight Installation Cost Calculator to build the full quote.
Set the leak warranty
State the labor warranty in the quote and what it covers. A skylight with a good warranty is an easier sell at a higher price.