Spiral Stair Kits Support and FAQs

Depending on where you plan to install your spiral stair, there are two critical measurements for ordering.

First, you need to measure finished-floor to finished-floor height. For the base of the stair, that’s easy. For the top of the stair, you can’t just measure to the ceiling height. If you’ve already cut your well opening, simply measure to the top of the opening, including finished floor. If you have not yet cut your well opening, you must factor in the height of your rafters, subfloor (usually 3/4″ plywood) and the thickness of your finished floor (wood, tile, carpeting, or other).

For standard, square “through-the-floor” installations, the second measurement that you’ll need is your proposed well opening. Your finished well opening must be 2″ larger overall than the diameter of the stair you plan to install. Remember, this is a finished measurement, so please factor in the width of any wood, drywall, or other finishing you plan to use to complete your well opening.