Renovation
Stair measurements to take before a renovation
The room, opening and floor measurements to collect before redesigning a staircase, from finished heights to obstructions and slab thickness.
Measure finished heights
Before a renovation, take your stair measurements from finished floor to finished floor wherever you can. If the finishes are changing, note both the existing levels and the expected final ones.
A few millimeters of floor build-up per level can change the riser height enough to matter.
Measure the available footprint
Measure the maximum length and width available at the lower level, and note obstructions such as doors, radiators, beams and built-in furniture.
For a turning stair, record the usable space in both directions as well as the overall room size.
Document the opening
Measure the stairwell opening’s length, width and offset, plus the slab thickness. Photos from above and below catch details the numbers miss.
If the opening will change, model the new one before structural work starts.
Put this into practice
Open the editor and test these numbers on your own staircase, with live drawings and a comfort score. No account needed.
Related guides
Stair calculations
How to calculate stair rise and run
Work out stair riser height, going, pitch and total run from your floor-to-floor height, with the typical ranges to aim for before you build.
Comfort
Using the Blondel formula for comfortable stairs
What the Blondel formula (2h + g) measures, why the target sits near 600 to 640 mm, and how to use it to balance riser height and tread depth.
Planning
Stair headroom: what to check before building
How stair headroom depends on the floor opening, slab thickness and finishes, and the layout mistakes that cause clearance problems near the top of a flight.