The Stairway Labor Trap
Many deck builders price their decks purely by the square foot (e.g., $65 a sq ft for composite). This works fine for the main deck platform. It is a catastrophic way to price the stairs.
A 12x12 deck platform might take your crew two days to frame, deck, and picture-frame. A 14-step custom cascading stair system with landings, continuous graspable handrails, and low-voltage riser lighting might take the exact same crew three full days to build.
If you bury the stair cost in the overall square footage price, you are doing the hardest, most liability-heavy work for free.
Calculating Stringers and Rise/Run
Stairs require precise mathematical calculation before the first board is cut. The Total Rise (height from ground to deck surface) must be divided perfectly so that every single step has the exact same rise (usually between 7 and 7.5 inches). Code dictates that there cannot be more than a 3/8" variance between the tallest and shortest step.
To achieve this, your carpenters have to spend significant time calculating, laying out, and cutting the stringers. For composite decking (which is flexible), you must install stringers at a maximum of 12-inch centers, not 16-inch, meaning you need more lumber and more labor.
Railing and Lighting Integration
Stair railing is significantly harder to install than level deck railing. The posts must be perfectly plumb, and the rail panels must be cut at the exact angle of the stairs (typically 32 to 35 degrees).
If the homeowner wants riser lights, you must route the low-voltage wire before the decking goes down, which slows down the framing process. Always quote stair lighting as a premium add-on, charging at least $150 per light fixture to cover both the material and the tedious wiring labor.