Why does new carpet smell and how long does it last?

What you are actually smelling

Most broadloom carpet is built with a latex compound that locks the tufts into the primary backing and bonds the secondary backing to it. That latex keeps giving off small amounts of volatile organic compounds for a while after it leaves the production line, and one of them, 4-phenylcyclohexene, is the one usually named as the characteristic new carpet odor. It is a byproduct of the latex rather than anything added on purpose, and it is the reason the smell is recognizable across products from different mills.

The carpet is not the only source in the room either. A new cushion has a smell of its own, particularly bonded urethane made from recycled foam, and cushion is a bigger share of what you are noticing than most people assume. Seam adhesive contributes on a stretched in floor. A full spread glue down contributes a great deal more, because there is adhesive under every square foot instead of a strip at each joint. So does the plastic the roll was wrapped in at the mill and shipped across the country in.

Why the first day is the worst of it

A roll of carpet spends weeks tightly wrapped, and everything it has been giving off in that time has been trapped in the wrapping with it. The strongest moment is the moment it is cut open and unrolled in your house. Once it is spread flat in an open room the concentration drops off quickly, and from there it comes down on a curve rather than switching off on a particular day. The first evening is not a preview of the next month.

What actually shortens it

Air exchange. That is the entire list, and everything below is just a way of getting more of it.

• Open windows, ideally on two sides of the room, so air moves through instead of sitting.
• Run the furnace or air conditioner fan continuously for the first few days rather than letting it cycle. A house that is exchanging and filtering air clears faster than one holding its breath.
• Put a box fan in a window facing out. Pulling the room's air outside works better than a fan stirring it around inside.
• Keep the room warm rather than cold. Offgassing runs faster at higher temperatures, so a warm, well ventilated room gets it over with sooner than a cold sealed one.
• Vacuum, and keep vacuuming. It lifts loose fiber and manufacturing residue out of the pile instead of leaving it there.
• Leave interior and closet doors open so nothing sits in a pocket of still air.
• Skip the shampoo, the sprays and the plug ins. Wet cleaning a brand new carpet adds moisture it does not need, and a masking scent is one more smell in the room, not one fewer.

How long it lasts

Honestly, it tracks the air more than the carpet. Most households stop noticing it within the first several days when the room is being aired properly, and it hangs around longer in a house sealed up against a January cold snap with every window shut. It fades either way. There is no fixed number to give you, because what is really being measured is how many times the air in that room gets replaced. If a strong smell is still obvious after a couple of weeks of genuine ventilation, that is worth a call to 636-332-0654 rather than more waiting.

If somebody in the house is sensitive to smells

Say so before you order rather than after the floor is down, because it changes what belongs on the sample list. A flooring showroom is not a doctor's office, so if someone in the house has asthma, a chemical sensitivity or any other reason to be careful, that is a conversation for their physician and not for us. What we can do is tell you plainly what is going into the room and let it steer the selection.

• Ask how the floor will be installed. A stretch in over tack strip uses adhesive only at the seams. A full spread glue down puts it under the whole room.
• Ask what the manufacturer publishes about emissions for a specific product. Low emission certification programs exist for carpet, cushion and adhesive, and the documentation is a fair thing to ask for by name.
• Look at the cushion as closely as the carpet, since it is a real share of what you smell. What the cushion does mechanically is worth reading either way.
• Think about the season. Installing when the windows can stay open for a few days is easier than installing in the middle of an ice storm.
• An empty room is the easiest room to ventilate, so plan the airing for before the furniture goes back in.

A smell that shows up later is a different problem

Everything above is about an odor that arrives with a new floor and leaves. A smell that appears months later, or comes back whenever the weather turns humid, is not offgassing and it will not air out. It usually comes from underneath: an old accident that soaked through the previous carpet into the cushion and the subfloor before any of it came out, or moisture working its way up through a slab. The fix for that lives in the subfloor and the backing rather than in the carpet you can smell. Moisture barrier construction exists for the first case, and rooms below grade have their own set of rules. The carpet page covers the constructions themselves, and a free in-home measure is the point at which a subfloor with a history turns up, rather than a year after new carpet went over it. Call 636-332-0654.