How to look after a carpet that will outlive you

A hand-knotted carpet is a structural object. The knots are tied around warps that run the full length of the piece, and every one of them is doing a job. Treated sensibly, wool of this kind lasts three or four generations. Almost everything that shortens that life comes down to water, sunlight, or a machine that was never meant to touch it.

Vacuuming

Vacuum with suction only. A beater bar — the rotating brush in most upright cleaners — grabs the pile and tears knots loose over months, and the damage is invisible until it is severe. If your machine cannot switch the brush off, use the hose attachment.

• Once a week in a room that gets used, less in one that does not.
• Go with the pile, not against it. Run your hand across the surface: one direction feels smooth, the other rough. Follow the smooth one.
• Never vacuum the fringe. Comb it out by hand instead — a vacuum head will pull the warps out one at a time.

Spills

Blot, do not rub. Rubbing pushes the spill down the fibre and into the foundation, where it is no longer your problem to solve but a cleaner's. Press a white cloth down firmly, lift, move to a dry part of the cloth, repeat until nothing more transfers.

Wool holds its own weight in water before it feels wet. That is why a small spill looks harmless and a large one is an emergency.

Then dry it properly. A damp foundation left overnight in a warm room is how you get dry rot, and dry rot is the one form of damage we cannot repair invisibly. Lift the carpet, prop it so air reaches both faces, and put a fan on it.

Sunlight

Natural dyes fade gracefully and evenly; that soft tonal drift in an old carpet is called abrash and it is part of why antique pieces are beautiful. What is not beautiful is a hard line where a sofa sat. Rotate the carpet 180 degrees once a year and the fade stays even.

Professional washing

Every five to seven years, and only by someone who washes carpets by hand and by immersion. Steam cleaning, dry cleaning and anything involving a truck-mounted machine will set the dyes running or leave detergent in the foundation that attracts dirt faster than before. We wash anything bought from us at cost, for as long as you own it.

Moths

Moths eat wool that is undisturbed, dark and slightly soiled. A carpet in a busy room is essentially safe. A carpet rolled in a cupboard is at risk, so check it every few months, and store it rolled — never folded, which cracks the foundation along the crease — with the pile facing inward.