UK staircase rise and going regulations: a measuring method

UK staircase rise and going regulations: start with the right guidance

The first check is where the stair will be built. Building requirements differ across England, Wales, Scotland and Northern Ireland, so a single set of dimensions should not be treated as a UK-wide rule. In England, the relevant government guidance is Approved Document K, which covers protection from falling, collision and impact. Identify the applicable national guidance before using any dimensions in a drawing or quotation.

The type of stair matters too. Approved Document K distinguishes a private stair serving one dwelling from stairs used for other purposes, and its dimensional guidance varies accordingly. For an ordinary private stair in England, it gives a rise of 150 to 220 mm, a going of 220 to 300 mm and a maximum pitch of 42 degrees. Confirm that your proposed stair fits that category before relying on those figures.

Measure between finished floor levels

Measure vertically from the finished surface of the lower floor to the finished surface of the upper floor. This floor-to-floor height is the total rise that every riser must share. Do not measure only to an unfinished subfloor if carpet, tiles, underlay or another finish will change the final level. Record the intended finishes at both ends of the stair alongside the measurement.

Take the measurement at more than one accessible point and investigate any difference before calculating. A laser measure or tape can establish the height, but check its reference points carefully. For work in an existing house, note any uneven floors rather than assuming the structure is perfectly level. The useful input for the calculation is the height the completed stair will actually connect.

• Record the lower finished floor level.
• Record the upper finished floor level.
• List any floor finishes that have yet to be installed.

Choose a whole number of equal risers

Divide the total rise by a whole-number riser count to find the rise of each step. If the result falls outside the range for the applicable stair type, try a different count and calculate again. A fractional number of risers cannot be built as planned, and making the last step a different height is not a sound way to absorb a remainder. Keep the calculated rise to enough decimal places while planning, then check the buildable dimensions on the final drawing.

For an explicitly illustrative 2,600 mm floor-to-floor height, 14 equal risers give 2,600 ÷ 14 = about 185.7 mm per riser. That sits within the private-stair rise range stated in England's Approved Document K. It does not, by itself, establish that the stair will fit or comply. The going, pitch, available space and other details still need checking.

Calculate goings and the space they need

The going is the horizontal distance between successive step nosings; it is not the same as the total depth of a tread with an overhang. Mark successive nosing positions on a plan so the measurement is unambiguous. In a simple straight flight where the upper floor forms the final landing, there is commonly one fewer going than risers. Check that assumption against the actual stair layout rather than applying it automatically to a turning stair.

For the illustrative 14-riser straight flight, 13 goings of 250 mm give 13 × 250 = 3,250 mm between the first and last nosing positions. A 250 mm going is within Approved Document K's stated range for a private stair in England. This calculation is not the complete footprint: landings, wall clearances and the details at each end also need space. Draw those elements to scale before deciding that the flight fits.

Check pitch, headroom and the surrounding layout

Rise and going must be checked together, because a steep combination may fail the applicable pitch guidance even when each individual measurement appears acceptable. For the illustrative dimensions, 185.7 ÷ 250 is about 0.743, giving a pitch of approximately 36.6 degrees. That is below the 42-degree maximum stated for a private stair in England's Approved Document K. Verify pitch from the final proposed dimensions, not from a rough sketch.

Next, draw the stair in section and mark the ceiling, floor opening and any sloping roof. Check headroom along the route using the applicable guidance, and look for obstructions such as beams or light fittings. Show the landings and nearby doors on the plan so a door swing does not compromise use of the stair. Handrails, guarding and other stair details also need their own checks; a passing rise-and-going calculation does not cover them.

Turn the calculation into a buildable specification

Give a stair designer or supplier the measured finished floor-to-floor height, proposed riser count, calculated rise, going and available plan space. Include the position of the upper opening, walls, doors and any restrictions affecting headroom. State whether the floor finishes are already installed or are still proposed. This helps the supplier check the same completed levels that you used in the calculation.

Ask for a dimensioned drawing showing each rise, the nosing-to-nosing going, pitch, landings and relevant clearances. Compare it with your site measurements before approving fabrication. If the design changes to a winder, quarter-turn or another layout, repeat the checks using that layout's details. Where classification or approval is uncertain, raise it with the relevant building control body before committing to construction.

Verification checklist

Re-measure the finished floor-to-floor height before the stair is made, especially if either floor build-up has changed. Recalculate the equal rise using the final height and the stated whole-number riser count. Compare the proposed rise, going and pitch with the guidance for the correct nation and stair type. Check that the drawing shows enough space for landings and a usable route.

After installation, measure the completed rises and goings rather than relying only on the order drawing. Pay particular attention to the first and last risers, where changed floor finishes can affect the finished dimensions. Check headroom and nearby door movement on site. Keep the final drawing and measurements with the house records.

• Correct national guidance and stair type identified.
• Finished floor-to-floor height confirmed.
• Equal risers, goings and pitch checked from final dimensions.
• Landings, headroom, doors and finished stair checked on site.

Scope and limitations

This note helps householders organise measurements and understand the calculation. It does not replace an on-site decision by a designer, installer, contractor, or manufacturer. Fabrication, structure, electrical work, gas, waterproofing, and personal safety require suitably qualified verification.