How do I protect the rest of the house during building work?
The barrier, the airflow that makes it work, and the protection that goes down before anything else. Plus what to do about the vents, the flue and the carpets you are keeping.
- Difficulty
- intermediate
- Time
- 10 min
- Read
- 5 min
- Safety
- warning
Short answer
Seal the work room with a taped barrier across the opening, and put a fan in the window blowing OUT — that puts the room at lower pressure than the house, so air moves from clean to dirty and dust cannot travel the other way. Protect floors with hardboard or corrugated sheet, not just dust sheets. Tape over every vent, extract and open flue in the room. Clean up wet or with a vacuum rated for fine dust.
Most of the damage a renovation does to the rest of a house is done by dust and by traffic, and both are almost entirely preventable for a fraction of what putting them right costs. The part people get wrong is the airflow: a sheet hung across a doorway does very little on its own, because dust travels on air and air goes round it.
Safety
Step by step
- Build a real barrier, not a hung sheet.Heavy polythene taped to the frame all round, including along the floor. Zip doors are cheap and worth it — a barrier you have to unpick to pass through gets left open. Two layers with a gap between them is better than one at the same cost.
- Get the airflow the right way round.A fan in the window of the work room blowing outwards puts that room at lower pressure than the house. Air then moves from the clean side towards the dirty side, and dust cannot travel against it. A fan blowing inwards does the exact opposite and pushes dust through every gap you did not find.
- Seal the floor gap, because that is the one that matters.Dust settles, so the leak that counts is at the bottom. Tape the barrier down to the floor rather than letting it hang, and put a tack mat on the clean side so what is on your boots stops there.
- Protect floors properly.Dust sheets stop paint splashes and do nothing about a dropped tool or a wheelbarrow. Hardboard, corrugated plastic sheet or a proprietary floor protector, taped at the joints, is what protects a floor you are keeping. On carpet, a self-adhesive protective film is quick and works.
- Protect the route as well as the room.Everything comes in and goes out through the hall and often up the stairs, and that route takes more traffic than the work room. Protect the stair treads, the nosings, the newel post and the handrail — a scuffed handrail is more visible afterwards than a marked floor.
- Tape over vents, extracts and any open flue.Otherwise dust travels through the ducting into other rooms. An open chimney in a room being stripped will take dust up and deposit it in the room above if the flue is shared or the pot is not capped.
- Cover what you cannot remove.Fitted units, radiators, sanitaryware, switch plates and anything wall-mounted that is staying. Sheeting taped down, not draped. A radiator sheeted at the top and open at the bottom fills with dust, and it will come out again for months.
- Leave the room sealed after the noise stops.Fine dust stays airborne for hours after the work finishes. Keep the barrier up and the fan running for a good while before anyone opens it, and clean up before taking the barrier down rather than after.
- Clean up wet, or with the right vacuum.Dry sweeping puts the whole of the fine fraction back into the air, which is the fraction that gets into lungs. Damp down, wipe rather than brush, and use a vacuum rated for fine construction dust — a household vacuum blows it straight out of its exhaust.
Tips
- Ask a builder at quote stage what protection is included and what they will do about dust. The answer tells you a great deal about how the job will go, and it is a fair thing to have in writing.
- Corrugated plastic floor sheet is reusable and takes far more punishment than hardboard. If a project runs to several rooms it pays for itself in the first week.
- Photograph the condition of every floor, stair and wall on the route before anything starts. It costs ten minutes and it settles any argument at the end.
Common mistakes
- Hanging a dust sheet across the doorway and calling it a barrier — Dust moves with air, and air goes round a loose sheet freely. Without a seal and without a pressure difference, the sheet is decoration.
- Putting the fan in the window blowing inwards — It pressurises the work room and drives dust into the rest of the house through every gap. It is the exact opposite of what is wanted and it feels equally sensible, which is why it happens.
- Dry-sweeping at the end of the day — It re-suspends the fine dust, which is the part that reaches deep into the lungs. Damp down and wipe, or use a vacuum rated for the job.
- Relying on dust sheets over a floor being kept — They stop splashes and nothing else. A dropped chisel goes straight through one.
If it doesn't work
Dust is appearing in rooms nowhere near the work
Cause: Air moving the wrong way, or dust travelling through ducting, a shared flue or a floor void — Fix: Check the fan direction first, then tape every vent and extract in the work room, then look at floor voids and gaps around pipes — a stud wall or a suspended floor connects rooms in ways that are not obvious.
The barrier keeps being left open
Cause: It is inconvenient to pass through — Fix: Fit a zip door. It costs very little and it is the difference between a barrier that works and one that is propped open by mid-morning.
A carpet you are keeping has been walked on for a week
Cause: Protection went down on the work room and not on the route — Fix: Protect the route now, and have the carpet professionally cleaned at the end rather than trying to sort it mid-project — grit worked into a carpet keeps cutting the fibres.
Questions people ask
Do I need a negative air machine?
For a domestic job, a decent fan in the window and a sealed barrier does most of it. Hired air scrubbers with filtration exist and are worth it for a long, dusty job, particularly with someone in the house who has a respiratory condition.
What mask do I need?
A disposable dust mask is not adequate for silica. A properly fitted FFP3 respirator is the general answer for construction dust, and fit matters more than rating — a good mask over stubble seals badly.
Is it worth moving out?
For a whole-house strip, often yes. For one room, a good barrier usually makes it liveable. The deciding factors are usually whether the kitchen or the only bathroom is out of use, and whether anyone in the house has a lung condition or is very young or very old.