Choosing a pad by the rug is only half the decision. The floor underneath rules out different options in each case, and getting it wrong damages the floor rather than the rug — which is the more expensive of the two mistakes.
The short version
| Floor | Use | Never use |
|---|---|---|
| Hardwood, finished | Felt + natural rubber | PVC, vinyl, synthetic rubber |
| Hardwood, oiled or waxed | Pure felt | Anything with rubber |
| Engineered wood | Felt + natural rubber | PVC, adhesive-backed |
| Laminate | Felt + natural rubber, thin | PVC, anything tacky |
| Vinyl / LVT | Pure felt only | All rubber, PVC |
| Tile, ceramic or porcelain | Felt + natural rubber | Adhesive-backed |
| Stone, sealed | Felt + natural rubber | PVC |
| Stone, unsealed or porous | Pure felt | Anything with rubber |
| Concrete, polished | Felt + natural rubber | PVC |
| Fitted carpet | Thin natural rubber gripper | Felt |
| Radiant / underfloor heating | Thin felt + rubber | Thick felt |
Hardwood
The most common case, and the one where the wrong pad does the most damage.
Use felt with a natural rubber backing. The felt protects the rug's foundation from grinding against the boards; the natural rubber grips without reacting with the finish.
Never PVC, vinyl or synthetic rubber. This is the specific failure mode worth understanding, because the pads that cause it are the cheapest and most widely sold. Over a few years the plasticisers migrate out of the pad, react with polyurethane and similar floor finishes, and leave either a sticky film or a permanently discoloured outline printed into the floor in the shape of the pad's waffle pattern. Removing it means sanding and refinishing.
Oiled and waxed floors are a different case
Hardwax-oil and traditional wax finishes are softer and more permeable than polyurethane, and rubber of any kind — natural included — can mark them. On an oiled floor use pure felt and rely on the rug's own weight, or on furniture, to hold it. Check the finish manufacturer's guidance if the floor is new enough to have any.
Hardwood also raises the question of what happens under the rug over years: best rugs for hardwood floors covers the uneven-ageing issue, which is a real consideration on a floor that will patinate around a rug that never moves.
Engineered wood and laminate
Both take felt with natural rubber, and both want it on the thinner side.
The consideration specific to laminate is its surface: a hard photographic wear layer that is slick, so grip matters more than it does on real wood, and unforgiving of anything that traps grit — a pad also stops sand working between rug and floor and scratching the wear layer.
Vinyl and LVT
The one flooring type with a genuine, well-documented incompatibility, and it is worth being categorical about it.
Use pure felt. Do not use rubber of any kind.
Vinyl and luxury vinyl tile react with rubber compounds — natural and synthetic — and the result is a yellow or brown stain that permeates the material rather than sitting on it. It is not removable, and the repair is replacing the affected planks. Rubber-backed mats, rubber furniture feet and rubber-soled shoes cause the same thing on a smaller scale.
Manufacturers of vinyl flooring generally state this in their care documentation, and it is worth checking yours specifically, because a few products are formulated to tolerate it.
Tile and stone
Sealed tile, porcelain and sealed stone take felt with natural rubber without any issue, and grip matters here because hard smooth floors are where rugs slide most.
Unsealed or porous stone — some limestone, travertine, unsealed slate, terracotta — can absorb compounds from a rubber backing and discolour. Use pure felt.
Tile has a second consideration: grout lines. A thin pad telegraphs the grout pattern through a low-pile rug over time. A 6–10mm felt pad prevents that.
Concrete
Polished or sealed concrete takes felt with natural rubber.
Unsealed concrete is porous and — more importantly — it can transmit moisture from below. On an unsealed slab or a basement floor, a pad that allows some airflow is worth having, and the rug should be lifted and checked periodically. A rug lying flat on damp concrete will grow mould in the foundation regardless of anything else you do.
Over fitted carpet
The reversal: here you want grip and nothing else.
The cushioning is already present, so a felt pad simply adds height and instability. What is missing is friction, because a rug on carpet has nothing to hold it — which is why rugs over carpet ruck constantly and why most people conclude it does not work.
Use a thin natural-rubber gripper, or a purpose-made rug-on-carpet pad. Full method, including the sizing difference, in how to put a rug over carpet.
Underfloor heating
Both a floor question and a rug question.
Keep the pad thin. A thick felt pad is an insulator, which is the opposite of what the system is for — it reduces heat output into the room and can drive floor temperatures up underneath. Use a thin felt-and-rubber pad, typically 3–5mm, or check whether the system manufacturer specifies a maximum thermal resistance for floor coverings. Many do.
Check the rug too. A thick high-pile rug over underfloor heating has the same effect. A low-pile or flatweave rug is the better companion to a heated floor, and it is one of the few situations where pile height is decided by the floor rather than the room.
What this leaves you with
Two rules cover almost every case. Rubber is the variable — it is what grips, and it is what reacts, so the floor's tolerance for rubber decides the pad. And PVC is never the answer, on any floor, at any price.
Then size it: about 25mm smaller than the rug on every side — what size rug pad do you need. The full comparison of pad constructions is in types of rug pad.
Common questions
What rug pad is safe for hardwood floors?
Felt with a natural rubber backing, or pure felt if the rug is heavy enough not to move. Avoid PVC, vinyl and synthetic rubber entirely — their plasticisers react with polyurethane floor finishes and leave a sticky residue or a permanently discoloured outline in the shape of the pad.
Can you put a rug pad on vinyl or LVT?
Only pure felt, and even then check the flooring manufacturer's guidance. Vinyl and luxury vinyl tile are the most reactive surfaces in a house: rubber of any kind can stain them permanently, and the damage is usually irreversible short of replacing the affected planks.
Do you need a rug pad on carpet?
Yes, a different one. A rug on carpet needs a thin natural-rubber gripper rather than a felt pad — cushioning is already there, and what is missing is grip. Without it the rug rucks constantly, which is why most people give up on rugs over carpet.