Why isn't a domestic vacuum cleaner enough after a building site?

Household dust is mostly textile fibres, skin cells and hair: large, soft, light particles, between 50 and 500 microns. They are captured easily and wear nothing down.

Construction dust is an entirely different matter:

• Plaster and sanding filler: essentially between 1 and 30 microns. Extremely volatile.
• Tile and concrete cutting: mineral fines under 10 microns, mixed with abrasive chips.
• Cement and dry laitance: alkaline, hygroscopic particles that clump as soon as they meet moisture.
• Sawdust and wood shavings: high volume, low density, filling a tank within minutes.

Two properties change everything compared with housework: these particles are abrasive — they wear down the motor, the hose and the lid seal — and they are fine enough to pass straight through a standard filter.

A 5-micron particle takes several minutes to settle in a draught-free room: this is what dictates the top-down order imposed on the three passes of a site, described in the sequence of a post-construction clean.

Four failures, almost always in this order.

Clogging. A standard bag or pleated filter saturates with fines within minutes. Suction collapses, the vacuum appears to stop working, and the user pushes the machine harder, believing it lacks power.

Overheating. A domestic vacuum motor is cooled by the airflow passing through it. Clogged filter, no more flow, no more cooling: the thermal cut-out trips, or the winding burns out.

Abrasion. Mineral fines that get past the filter reach the turbine and the bearings. It isn't immediate, but it is permanent.

Cement plus moisture. A damp tank bottom and cement dust set solid inside the machine. It cannot be recovered.

A household vacuum isn't undersized for a building site: it is built for a different job. It is the same reasoning behind the professional equipment we use.

This is the only figure that matters, and it almost never appears on a consumer vacuum.

Site vacuums are classed by the amount of dust they let pass back into the room's air:

• Class L — low-risk dust, pass-through rate around 1%. Sawdust, fine gravel.
• Class M — medium-risk dust, pass-through rate below 0.1%. Plaster, hardwoods, fillers. This is the serious minimum on a finishing site.
• Class H — high-risk dust, pass-through rate below 0.005%. Crystalline silica, mould, mineral fibres.

A so-called high-efficiency filter — HEPA filtration — retains at least 99.95% of 0.3-micron particles, the hardest size to capture, since it is too small to be stopped by impact and too large to be trapped by diffusion.

A domestic vacuum without a certified filter releases a significant share of what it takes in. In practical terms: the room is vacuumed, the air is loaded, and the dust settles back on surfaces washed two hours earlier. That's the origin of the feeling that "the dust keeps coming back".

The marketing argument for consumer vacuums is about electrical power drawn. It says nothing about actual suction capacity.

Two figures matter, and they pull against each other:

• Vacuum pressure, in millibars or water column: the force that lifts a particle stuck to the floor.
• Airflow, in cubic metres per hour: the volume that carries that particle to the tank.

Strong vacuum pressure with weak airflow lifts the dust and lets it fall back inside the hose. That's what happens with a small-diameter domestic hose the moment it starts loading up. Site vacuums use hoses with a noticeably wider bore and prioritise airflow, precisely to carry heavy matter such as gravel or dry laitance without the hose choking.

Three further features are absent from a domestic appliance: filter shaking during use, a tank holding several dozen litres — a site fills a 3-litre bag in one room — and the ability to draw up water, essential for rinsing floors.

This section has nothing commercial about it, which is exactly why it is here.

Dry cutting and sanding of concrete, tiles, porcelain stoneware and certain fillers release respirable crystalline silica: particles fine enough to reach the alveoli of the lungs and lodge there. Repeated exposure is a recognised occupational risk across the whole construction sector.

Three practical consequences:

• Do not sand or dry-cut without source extraction or appropriate respiratory protection. A paper DIY mask does not filter these particles.
• Do not vacuum cutting dust with a machine that releases it, which amounts to putting it back into suspension at breathing height.
• Ventilate and let it settle before working in a room that has just been cut.

This is one of the reasons why dust removal on a building site is a distinct trade from housework, not a more intense version of it — a comparison developed in our article on post-construction cleaning and standard housekeeping, two different trades.

On a site, the machine is not only there to remove dust. It comes into play three times a day, at three different moments:

1. During top-down dust removal, with a brush attachment, from ceiling to skirting, never wetting anything.
2. When the floors are washed, to extract dirty water loaded with laitance. This is the decisive point: without extraction, the loaded water is squeegeed towards a drain and redeposits its cement as it dries, until it forms a white bloom.
3. During the final rinse, between two changes of clean water, until every trace of foam is gone.

The tank is emptied between rooms, never at the end of the day: a full tank loses its vacuum pressure. And the hose is rinsed out, otherwise laitance dries inside it and permanently narrows the bore.

On a small area, after light works, with an appliance you accept losing:

• Hire a site vacuum rather than use your own. It's cheaper than a motor.
• Never use a broom. Sweeping puts most of what it moves back into suspension, and the dust resettles over the following hour.
• Never wet anything before everything has been vacuumed dry. Water on plaster dust produces a paste that sticks and then takes twice as long to remove.
• Vacuum top to bottom, room by room, closing each finished room.
• Change the bag or clean the filter as soon as suction weakens, not when the tank is full.
• Plan two full passes 24 hours apart: what was in suspension during the first pass will have settled by the second.

Beyond a single room and light works, the question stops being about equipment and becomes about time: a full post-construction clean is carried out by a team of 3 and priced per square metre of floor — 20 MAD/m² incl. VAT on standard tiles, 30 MAD/m² incl. VAT on other floors, with a studio minimum of 2,000 MAD incl. VAT — as set out in post-construction cleaning prices.

How the result is checked is described in the document ticked off before handover. For an estimate, confirmed afterwards on photos, describe the floor area and the nature of the works.