How often should office carpet be cleaned?

Almost everything that dirties office carpet comes in through the door, under the soles of shoes. In Marrakech, that load is overwhelmingly mineral: sand, street dust, building-site particles. It is abrasive, and that is what makes it costly.

The single most cost-effective line in a maintenance plan therefore sits before the carpet itself.

• Length matters more than quality. An entrance mat only works if a visitor's foot lands on it several times. A one-metre mat at the entrance of an office floor is a decorative object.
• Two zones beat one: a scraping section outside or at the threshold, an absorbent section inside.
• A saturated mat works in reverse. Once loaded, it releases dirt with every crossing. It has to be vacuumed at least as often as the zone it protects, and deep-treated at the same rhythm.
• The lobby, the lift and the landing count in the chain. Sand stopped at the landing never reaches the floor plate.

Every gram trapped at the entrance is a gram that will not cut a fibre further in. It is the only maintenance measure that costs once and pays back every day.

The standard reflex — a quick pass over the whole floor plate every evening — is the worst possible use of the time available. Dirt is not spread evenly, so the effort should not be either.

A useful vacuuming plan works on three levels:

• Every day: the entrance, the lobby, the main corridor, the route to the coffee machine and the meeting room. That is a few dozen square metres carrying most of the footfall.
• Two to three times a week: workstations, desk pedestals, the photocopier area.
• Once a week: the perimeter, the accessible undersides of furniture, corners, skirtings.

Three points of method change the result more than frequency does:

• Speed. A vacuum moves too fast in 90% of cases. On a traffic lane, several slow passes over the same spot are needed for suction to work in depth. Fast and everywhere is worth less than slow and in the right place.
• Crossed direction. A fibre laid flat in one direction does not release what it holds from the other side. One pass one way, one pass at right angles.
• The bag and the filter. A bag half-full has already lost part of its suction. It is the most common cause of a vacuum that "does nothing any more".

Between two annual extractions, there is an intermediate treatment few sites know about, and it answers exactly the problem of the traffic lanes.

The principle: a product is applied that coats the dirt particle in a polymer that crystallises as it dries. The dirt becomes a dry, brittle flake, detached from the fibre — and the following days' vacuuming removes it. The product dries fast, allowing the floor to reopen in one to two hours instead of overnight.

What it delivers: a quick visual catch-up of corridors and lobbies, without shutting the floor down, using very little water — so no risk of tile lifting or watermarking.

What it does not do: it extracts nothing. Deep-seated dirt stays in the carpet, and the mineral load built up against the backing is untouched. A site that replaces the annual extraction with repeated encapsulation sees its carpet degrade normally, looking fine right up until the day it does not.

The sensible position: encapsulation is interval maintenance, not a deep treatment, and it does not exempt a site from the annual extraction.

This is the most common complaint from site managers, and it is well founded. The culprit has a name: residue.

Rotary-brush shampooing — still offered by many providers because it is fast and cheap — works a detergent foam into the fibre, then the surface is vacuumed off and left to dry. Two structural problems follow:

• The dirt is not extracted, it is redistributed through the depth of the pile.
• The surfactant stays in the fibre. It is designed to cling there. Once dry, it turns sticky, and catches the next round of dust far more effectively than a bare fibre.

The observable result: the carpet looks clean for two to three weeks, then gets dirty faster than before cleaning, and the cycle speeds up with every round. On a floor treated this way for years, the traffic lanes become impossible to recover except through several successive extractions with a neutralising product.

Extraction rinsing is what tells the two approaches apart: the injected solution has to come back out carrying what it has lifted, which is checked by eye in the recovery tank — see the injection-and-extraction cycle in detail.

One question worth putting to any provider before signing: what happens to the water that goes into my carpet?

On an office floor, stains are few and always the same: coffee spilt near the machine, cartridge ink, tar tracked in from a nearby building site, stamp ink, and the classic meal eaten at a desk.

The decisive factor is not the product, it is the delay. A coffee stain treated within the hour almost always lifts; the same stain, found at the annual clean, has become an oxidised mark nobody will guarantee.

What works in practice:

• A kit kept in the cleaning cupboard, known to whoever is on site: white absorbent paper, two white cloths, a bottle of cold water, an absorbent powder for grease.
• A three-line written instruction: blot dry from the edge towards the centre, never rub, never hot water, never bleach, never stack products.
• Immediate reporting, even when no treatment is possible on the spot, with a photo and the time. That is the information that makes a follow-up visit effective.

What to avoid absolutely: a shop-bought multi-purpose stain remover applied generously by someone in a hurry. It leaves a bleached patch on a solution-dyed carpet, and a residue that turns into a dark mark three months later. The logic by stain family is explained in our guide to coffee, wine and grease stains (the French-language source article has no English edition yet).

This is a facilities reflex that costs almost nothing and saves difficult situations, and almost nobody has it.

On a carpet-tile floor, a tile is a spare part. An irreversible stain, a cigarette burn on a smoking terrace, a spilt toner cartridge, a one-off mishap: the tile is swapped in three minutes, and the floor is homogeneous again.

Two conditions for this to work:

• Keep the offcuts from the original fit. They must be stored flat, out of the light — a tile stored on edge warps, a tile exposed to daylight fades and no longer matches.
• Lift a tile rather than fit a new one on sight. A replacement tile, even from the same batch, has not carried the wear or the light of the rest of the floor. The right move is to take a tile from under a cabinet or a corner nobody uses, fit it in the visible spot, and put the new tile in the hidden corner. Nobody sees the difference.

A broadloom carpet does not offer that flexibility: any local repair shows, which changes the trade-off covered next.

The sum is simpler than it looks, and it comes up once a year.

Sand trapped at the base of the fibre cuts the pile with every footstep. A carpet that is never extracted does not just get dirty, it wears out mechanically from the inside: fibres are severed, density drops, the traffic lanes flatten for good. The process is invisible for three years, then irreversible.

Three markers to decide by:

• The traffic lane stays dark after extraction. If a grooming brush pass has not been enough, it is no longer dirt: it is crushing, and sometimes fibre loss. On a tiled floor, replace the zone; on broadloom, live with it.
• The backing shows through in places. The fibre is gone. No treatment brings it back.
• The smell persists after extraction. Check the underlay or the substrate: old water excess, a leak or rising damp calls for a building diagnosis before any further work.

As long as the fibre is there, maintenance is by far the better trade-off: an annual extraction costs a fraction of a full lift-and-relay, and pushes the deadline back several years. To get it priced, have three details ready: the area, the fitting method — tiles or broadloom — and a possible time slot outside working hours.

And if the floor is coming out of a refit, protect the carpet during the works with film or card laid on the floor; the hard floors, washrooms and windows are then brought back in a post-construction clean.