The short answer
You control dust at the source, not afterwards with a brush. Sand with a machine that is connected to a vacuum cleaner of the correct dust class, seal off your work zone from the rest of the house with dust barriers and film, and ensure negative pressure so that fine dust does not travel into the living spaces. Never clean up dry, as that will stir everything up again. And think of yourself: plaster and concrete dust contains quartz, so a good mask is not a luxury.
Why cleaning up afterwards is not sufficient
The finest sanding dust is precisely the dust that you cannot see and that penetrates your lungs and spreads throughout the house. By the time you start with the brush, it is already on cabinets, in curtains, in the ventilation, and three rooms away. In a lived-in renovation, this is doubly annoying, as people are living there in the meantime.
That is why only an approach that prevents dust from being released or spreading works. You catch it at the source, keep it in the work zone, and ensure that the air leaving your zone is filtered. Cleaning afterwards is then a finishing touch, not your only defence.
There is also a health aspect that is often underestimated. Dust from plaster, sand-cement, and concrete contains crystalline quartz, and that fine dust is harmful to inhale over long periods. That is the real reason why source extraction and a good mask are standard for this work, not just the comfort of a clean site.
Why the right grit is important
Sanding is a balance. If you take too coarse paper for a fine phase, you will create scratches that you will later see under your paint or varnish, because a thin finish layer does not mask those grooves. If you take too fine paper for coarse work, you will sand yourself silly without results, because the paper removes nothing.
That is why you work in steps. You start with a grit that is coarse enough for the job, and you work up to finer until the surface is ready for what comes next. Do not skip too many steps, as the scratches from the coarse grit will remain visible. Jumping from P80 straight to P240 leaves marks; working from P80 through P120 to P180 does not.
The grit also depends on your material and your goal. Removing old paint requires something different than preparing a wooden door for varnish or matting a wall for a new coat of emulsion paint. So first determine what you want to achieve, and choose the grit accordingly.
Step by step
- First, tackle the source. Sand with a sander that has integrated extraction, connected to a vacuum cleaner of an appropriate dust class for fine dust. A regular construction vacuum cleaner without a dust class simply blows the finest dust back out through the filter, so that is not the right choice here. There are also sanding blocks and sanding mesh with extraction for manual sanding, so that work does not have to mean dust-free either.
- Then zone your workspace. Separate the work zone from the inhabited zone with dust barriers or plastic walls with a zip, seal doors, and cover ventilation grilles and air ducts so that dust does not spread through the installation. Turn off the mechanical ventilation or system in that zone during sanding.
- Next, ensure negative pressure. Place an air purifier or extraction system with a fine filter that removes air from the work zone, so that air flows in instead of out. This way, dust does not carry into the rest of the house when you enter and exit the zone.
- Protect walkways and surfaces. Lay floor film or cardboard in the walkway, cover furniture and fixtures, and place a sticky mat at the exit of the zone so that you do not carry dust under your shoes.
- Wear the right protection yourself. A well-fitting dust mask is the minimum, and for a lot of dust or quartz-containing dust, choose a higher protection class. Also think about your eyes.
- Finally, clean up properly. Never sweep dry, as this will just send the fine dust back into the air. Let the dust settle first, then vacuum it up with a vacuum cleaner of the right class, and wipe the surfaces afterwards with a slightly damp cloth.
The mistake you should avoid
The classic mistake is sanding dry without source extraction with the idea that you will clean up afterwards. By then, the dust is already in the lungs and throughout the house, and you won't be able to get it all out with any cleaning. Capture it where it originates, then cleaning up remains limited.
A second pitfall is dry sweeping to finish quickly. A brush or broom stirs up exactly the most harmful fine dust, which then gently settles on everything you just thought was clean. Vacuuming with the right class and wet cleaning is the only way that truly removes the dust instead of just moving it.
What you need for this at PrepKing
Working neatly and safely in an occupied house starts with good preparation, and that is what Prepking is all about. With us, you will find sandpaper and sanding mesh with extraction holes, protective film and tape for your dust barriers and zoning, floor protection and a sticky mat for the walkway, and dust masks to protect yourself.
No sales pitches, just the right materials to keep the nuisance and risk low. Every surface, every time.
Related: which sandpaper to use for which job, and further on how to recognise lead paint in old homes and work safely with it, plus how to work safely indoors with smells and fumes.
