Guide · For the trade
Stair runner installation: what to specify and what to tell the installer
Stair runner installation is a half day to a day for a carpet installer on a straight 13 to 15 step stair: a runner 27 to 36 inches wide is stretched over a 1/4 to 3/8 inch dense pad on tackless strip at the back of each tread, fastened at each nosing, and finished either waterfall (falling straight from nosing to tread) or Hollywood (wrapped tight around each nosing). The designer's job is the spec, which fixes the method, the pad, the width and reveal, the landings and winders, and the rods before the installer arrives.
This guide is for the designer or the junior writing that spec and briefing the installer, anywhere in the country. It is a sub-page of our stair runner collection; fiber and construction are in the wool stair runner guide and the pad in the carpet pad for stairs guide. Interiors arranges installation through our installer network in the client's city, and this is the spec our installers work from.
Waterfall vs Hollywood stair runner: the first decision
Every spec names one of two methods.
| Method | What the installer does | How it reads | Specify it for |
|---|---|---|---|
| Waterfall | Stretches the runner over the tread, lets it fall straight from the nosing to the base of the next tread, fastens at the back of each tread | Soft, rounded step edge; the stair profile is implied; the pattern flows unbroken | Thicker Wiltons and loops, a traditional house, a rounded nosing, stair rods |
| Hollywood (upholstered) | Wraps the runner tight around the nosing, tacks it under the lip, then down the riser into the back of the next tread | Crisp, tailored; each step's profile shows through the carpet | Flatweaves, thin Wiltons and loops, a modern stair, a square or bullnose nosing the client wants to read |
Hollywood uses about 2 inches more runner per step and adds an hour or two. Thick cut piles do not wrap well; a 1/2 inch plush goes waterfall. Write the method on the drawing and the purchase order, because an installer left to choose will do waterfall.
What to tell the installer about the pad
Pad is on every stair runner installation, and the stair pad is not the room pad. Specify 1/4 to 3/8 inch of dense felt, felt-and-rubber or slab rubber, never the 7/16 inch 8 lb rebond from the bedrooms. Tell the installer to cut it 2 inches narrower than the runner, a separate piece per tread, from the tackless strip over the nosing. On finished wood, 1/4 inch felt-and-rubber with natural rubber down and the fewest staples. The numbers for every pad type are in the carpet pad guide.
Width, reveal and the fastening
Leave 3 to 5 inches of tread showing on each side: a 27 inch runner on a 36 inch stair, 32 on a 42, 36 on a 48. Have the installer snap a centerline and set the runner to it, not to the wall; stairs are rarely parallel to their walls. The runner is held by tackless strip at the back of each tread, set 1/4 inch off the riser with the pins angled up the stair, and by narrow-crown staples at the nosing: in the crotch where tread meets riser on a waterfall install, under the lip of the nosing on a Hollywood install, in the pile line either way so they do not show. Staple size, 1/4 to 3/8 inch leg and longer on a thick Wilton, is the installer's choice, not the spec's. No fastener-free method holds a runner on a stair for more than a season.
Landings and winders
Landings are where a stair runner installation goes wrong. The runner either turns as a runner, with a mitered seam at the corner so the pattern continues around the turn, which costs a step of yardage per turn and suits a striped or bordered runner; or the landing is carpeted as a field, wall to wall or as a cut-and-bound mat, with the runners entering and leaving it, which suits a large landing or a plain runner. Tell the installer which, and whether the landing edge is bound to match.
Winders, the pie-shaped treads on a turning stair, are cut and fitted one tread at a time, seamed at each riser so the seams sit in the shadow of the nosing. A solid, a heather or a small all-over pattern hides those seams; a stripe does not, and on a winder stair a stripe is a spec to talk the client out of. Allow an extra foot per winder.
Stair rods: decorative, specified separately
Stair rods sit in the crotch of each step over a waterfall runner, held by brackets screwed into the tread 1 inch outside the runner edge. On a tacked installation they are decorative, not structural; the runner is still stretched and fastened as if they were not there. Specify the finish, the finial, the diameter (1/2 inch standard, 5/8 or 3/4 inch on a wide stair) and the length, runner width plus 2 to 4 inches. On a stone stair where nothing can be tacked, rods do carry the runner, clamping it into a rubber pad with a different bracket; the order should say so.
What is the 25 rule for stairs, and what the runner does to it
The 25 rule is the geometry rule for a comfortable stair: two risers plus one tread should equal 24 to 25 inches, so a 7 inch riser pairs with an 11 inch tread and a 7.5 inch riser with a 10 inch tread. Code adds that risers in a flight may not differ by more than 3/8 inch. Carpet and pad change the arithmetic at the top and bottom steps only: the first step gains the thickness of pad plus runner, the last step loses it. A 3/8 inch runner over a 1/4 inch pad adds 5/8 inch, inside the tolerance; a 1/2 inch plush over 7/16 inch rebond adds 15/16 inch, which is why thick pad does not belong on a stair.
Over existing carpet, and over stone
A runner does not go over existing carpet: it compresses unevenly, the tackless cannot grip through it, and the stair becomes a slip. Specify removal of the old carpet and pad before the runner day; a wood stair under forty years of carpet often needs filling at the old tack lines and a coat of finish on the reveals, a separate trade on a separate day. On stone or tile, nothing is tacked: the runner is held by rods or a low-tack adhesive at the back of each tread over a 1/4 inch rubber pad.
What the installer needs from you
- The runner, its width, and the method: waterfall or Hollywood.
- The pad type and thickness.
- The step count, tread width, and every landing, winder and turn, with the landing treatment drawn.
- The reveal: inches of tread showing each side.
- Rods, with finish and bracket type, if any.
- Whether the reveals need refinishing first.
With those six lines on the drawing, our installer quotes the day and arrives with the right pad and fasteners. Yardage is 20 inches per step plus landings and one step for waste, per the wool stair runner guide. Add a half day per mitered landing and a day for winders.
Questions designers ask
Should a stair runner be installed by the carpet installer or the finish carpenter?
The carpet installer, one who does stairs weekly. A runner is stretched, not laid, and the fastening at each nosing is a carpet skill. The carpenter's part is the stair itself.
What is the 25 rule for stairs?
Two risers plus one tread should add up to 24 to 25 inches, and risers in a flight may not differ by more than 3/8 inch. A runner over a thin pad keeps the first and last step inside that tolerance; a room pad does not.
Can a runner go over existing carpet?
No. The old carpet and pad come up first and the runner installs over a 1/4 to 3/8 inch stair pad. A runner over carpet shifts, cannot be stretched tight, and is a fall hazard.
What does the installer fasten a stair runner with?
Tackless strip at the back of each tread and narrow-crown staples at each nosing, 1/4 to 3/8 inch leg, set in the pile line so they do not show. The size is the installer's call; the method and the pad are the spec's.
Waterfall or Hollywood for a flatweave runner?
Hollywood. A flatweave has no pile to soften a waterfall edge, so it reads best wrapped tight to the nosing. Waterfall is for Wiltons, loops and cut piles with body enough to round the step.
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