Why renovation dust keeps coming back

This is the most common complaint we hear after a renovation, and people usually assume they cleaned badly. Generally they did not. They cleaned the wrong 20 per cent, twice.

Renovation dust is not household dust

Household dust is mostly fabric and skin, it is soft, and it settles. Renovation dust is ground stone, cement, tile and timber. It is fine, hard, abrasive and light enough to stay airborne for a long time after the work has stopped.

That is why it gets everywhere and why it comes back: it never landed in the first place.

Where it is actually sitting

• The tops of things. Door frames, wardrobe tops, curtain rails, the top edge of skirting. Above eye level is invisible until light hits it.
• Inside every cabinet. Drawers, wardrobes and kitchen carcasses fill with it even when the doors stayed shut.
• Air-conditioning. Filters, fins and the housing. This is the big one, because the unit then redistributes it every time it runs.
• Ceiling fans and light fittings, which do the same thing at a different height.
• Grout, tracks and corners. Window tracks and sliding door channels pack solid and are never reached by a mop.
• Soft furnishings. Curtains, mattresses and sofas hold it and release it when disturbed.

Why dry sweeping restarts the problem

A broom or a dry cloth lifts fine dust back into the air, where it stays for hours and then settles onto the surfaces you have just finished. That is the loop people find themselves in.

If it looks clean and then looks grey again two days later, nothing was removed. It was just moved into the air and back down.

What actually breaks the cycle

Top down, with extraction rather than agitation, cabinets and tracks opened up and done individually, air-conditioning addressed rather than ignored, and the soft furnishings treated as part of the job instead of as furniture that happens to be in the room.

Then, and only then, floors. Doing floors first is the reason a flat gets cleaned three times.

The contractor sweep-out is not this

It is not meant to be, and that is not a complaint about contractors. It clears debris so the unit can be handed over. We have written about the difference in post-renovation cleaning: why the contractor’s sweep-out is not a clean.

The service is post-renovation cleaning.

How long it keeps arriving

Longer than anybody expects, and the reason is not that it is still being made. It is that fine dust settles slowly and is easily disturbed, so every time a door opens, a fan runs or somebody walks across a room, a portion of what had landed goes back up.

That is why a single clean into a home that is being moved into rarely holds. The move itself stirs everything that had settled since.

If you have a choice, deal with it properly while the unit is empty and accept one light pass afterwards, rather than the other way round.

The three things that are still releasing it

• Air-conditioning, which actively pushes it back out every time it runs.
• Soft furnishings, which hold a surprising amount and let it go when sat on or moved.
• Cabinet interiors and tracks, which are opened and closed daily and are almost never done properly the first time.

Deal with those three and the loop breaks. Ignore any one of them and the flat keeps going grey no matter how often the floors are mopped.

The air-conditioning side is in renovation dust and your air-conditioning.