Damp and mould in the bedroom
The bedroom is where mould appears most often in Portugal: two people release half a litre to a litre of water a night, with the door and window closed, in what is usually the coldest room in the house.
What it usually is
Black dots in the upper corners, behind the wardrobe and the headboard, drops on the windows when you wake up. Worse from November to March.
A patch with a brown outline, next to the window or on a top-floor ceiling, that gets worse 1–3 days after rain.
Only on a ground floor or basement: a band up to ~1 m from the floor, white salts, crumbling plaster.
What to check before you touch anything
- How high the patch is (measure it with a tape).
- Whether the wall is an outside wall and feels icy to the touch.
- The humidity at 7 am, before opening the window — above 70% for several days is a clear sign.
- Whether the mould came back less than 3 weeks after cleaning.
What you can do today
- 01Move the wardrobe and the bed 5–10 cm away from outside walls.
- 02Air the room for 5–10 minutes in the morning with opposite windows open — short and strong.
- 03Don't dry clothes in the bedroom, and close its door when drying clothes elsewhere.
- 04Clean the mould with diluted bleach (1 to 4), with gloves, a mask and the window open — never mix products.
Guides for this room
Frequently asked questions
The WHO links damp, mouldy homes with more respiratory symptoms and asthma, especially in children and sensitive people. It is not a reason for alarm, but it is a reason to fix the cause rather than just cleaning the patch. If you have symptoms, talk to your doctor.
It fixes many condensation cases if it runs at night with the humidistat at 50–55% and the door closed. It does not fix water ingress or rising damp — there it only dries the air while the wall stays wet.