Why it is usually a bad idea
- Safety — two layers of soft floorcovering create a spongy, unstable tread edge and the runner can creep underfoot.
- Wear — the runner cannot be tensioned properly over pile, so the nosing wears through fast.
- Appearance — the runner sits proud, the edges lift, and the outline of the carpet below shows through.
- Height — on the top step the extra build-up can create a genuine trip point at the landing.
The safe default
Lift the old carpet. On stairs it is a two-hour job, it exposes any tread damage while you can still fix it, and it is the difference between a runner that lasts fifteen years and one that lasts three.
When it can work
There are narrow cases where laying over the existing carpet is defensible: a very low-pile, tightly bonded contract carpet that is firmly fixed and in good condition; a short-term rental where you cannot alter the fabric of the property; or a temporary protective runner during building work.
How to do it as safely as possible
- Confirm the carpet below is low pile, firmly fixed and not loose anywhere.
- Choose a thin, low-pile runner — never a thick or high-pile one.
- Do not add underlay; the carpet beneath is already your cushioning.
- Staple through both layers into the crease, using longer staples than usual.
- Fix the nosing on every step, not just the crease.
- Check the top step for a trip hazard and address it before you finish.
What about non-slip stair treads instead?
If the goal is grip or protection rather than looks, individual stair tread pads are a better answer over existing carpet. They add no continuous length to trip on, come with adhesive backings designed for the job, and can be lifted individually to clean.
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.
Frequently asked questions
Can you put a stair runner over carpeted stairs?
It is possible with a thin, low-pile runner over a firmly fixed low-pile carpet, but it is not recommended. The runner cannot be tensioned properly, wears out quickly at the nosing and can create a slip hazard.
Will a runner over carpet damage the carpet underneath?
Yes. Staples leave permanent holes and the compressed strip under the runner will not recover, so the carpet beneath is effectively sacrificed.
Know your numbers in 30 seconds
Enter your step count, tread depth and riser height — the stair runner calculator gives you the exact length to order, in metres and feet, with waste included.
Plan the runner properly