Stair Runner for a Flat Conversion: What to Measure First

The particular quirks of converted staircases

A house converted into two or three flats usually keeps the original staircase for the ground and first floor, but a fire door, a stud partition, or a shortened flight partway up is common where a landing was split between units. If you're fitting a runner to an internal staircase that serves just your own flat, measure exactly as you would for any house, but if your flat's stairs are shared with another unit or lead to a communal front door, check your lease and any management company rules before ordering, since some conversions restrict what residents can fit in shared areas.

Converted staircases have sometimes had a step or two removed or added when floor levels were adjusted between units, so don't rely on an old estate agent's floor plan or the previous owner's description of the flight. Count and measure the actual steps in your particular flat, since even two nominally identical flats converted from the same house can end up with a different step count if the internal layout was split unevenly.

Internal vs shared staircases

An internal staircase entirely within your own flat, common in a maisonette-style conversion or a top-floor flat with its own private stairs, gives you full freedom over colour, pattern and fitting method, just like a house. A shared staircase serving multiple flats behind a communal front door is a different matter: fire regulations in many buildings require any covering on an escape route to meet a minimum fire rating, and freeholders or management companies often have specific rules about what can be fitted, sometimes requiring their approval before work starts.

How much runner do I need?

Take a 13-step converted flight with a standard 10 in tread run, 7.5 in riser height and 0.75 in nosing wrap, giving 18.25 in per step, or 237.25 in (19.77 ft) across the run. Add a 24 in finishing allowance for 261.25 in (21.77 ft). If the original staircase turn survived the conversion, add roughly 3 ft for the landing run, bringing the subtotal to about 24.8 ft, then apply an 8% waste margin for the extra cutting a turn involves, landing at approximately 26.8 ft.

In UK measurements, that's 25 cm tread, 19 cm riser and 1.9 cm nosing wrap for 45.9 cm per step, or 596.7 cm across 13 steps. Add 60 cm finishing allowance for 656.7 cm, plus roughly 0.9 m for a retained landing turn, giving about 7.46 m, then an 8% waste margin brings the total to roughly 8.1 m. On a straight internal flight with no turn, drop back to the standard 7-7.3 m figure for a 13-step run.

Choosing a runner that suits a flat's proportions

Flats tend to have narrower halls and a smaller overall footprint than the house they were converted from, so a busy, high-contrast pattern that would work in a wide Victorian hallway can feel cramped in a converted flat's narrower stairwell. A tonal or subtly patterned runner in a mid-tone colour generally suits these spaces better, and because a lot of converted flats have lower ceiling heights on upper floors, a lighter colour on the stairs helps the whole stairwell feel less boxed-in.

• Confirm whether your staircase is shared or entirely internal to your flat before choosing a style or fitting method.
• Count your actual steps rather than relying on the original house's staircase details.
• Check any fire-rating or freeholder requirements if the stairs serve more than one flat.
• Add a landing allowance only if your flat retained the original half-landing turn.
• Choose a tonal or lighter colour to help a narrower converted stairwell feel more open.

Ordering with confidence in a shared building

Because converted properties vary so much building to building, I'd always encourage a leaseholder to get their own tape-measure numbers rather than assume their flat matches a similar-looking conversion next door. Running those figures through a stair runner length calculator gives you a reliable estimate before you contact a fitter or place an order, and it's a useful number to have on hand if you do need freeholder sign-off, since it shows you've measured properly rather than guessing at what you'll need.

Stair runners fitted in flat conversions also tend to need a slightly more secure fixing method than a house, particularly on shared stairs with heavier daily footfall from multiple households, so ask your fitter about a gripper-rod combination rather than adhesive alone if the staircase gets constant use. It's a small extra cost that pays off in how long the runner stays properly seated before it needs re-tensioning.

Whatever you decide, get the numbers first: the stair runner calculator doubles as a stair runner length calculator, adding nosing wrap, landings, winders, pattern repeat and waste so you order the right length the first time.