Stairwell Opening & Headroom

How long to frame the stairwell opening so there's full headroom all the way down — or the headroom an opening you already have gives. Free, no sign-up.

Headroom is measured plumb from the line through the tread nosings up to the underside of the floor above. Going down the stair, the tightest spot is right under the far edge of the opening, so that edge sets how long the opening has to be.

Floor thickness is everything from the top of the finished floor above down to the finished ceiling under it at the opening's edge: flooring, subfloor, joists or header, and drywall.

The opening length is measured level from the face of the top riser (the header the stair hangs from).

Taulien Construction · Fredericton, New Brunswick · info@taulien.com · 506-230-5131