Décoration/ventilation assistance

Hello,

Short story: I refurbished a 22 m² studio (north wall, ground floor with courtyard view). I removed the old wallpaper, painted with a light mineral paint, and set up a cozy sleeping area behind a slatted shelf. Perfect... until the first rainy weekend: basement smell, small black spots on the back of the mattress and rings on the cold wall.

In the living area, I ventilate morning/evening, added a dehumidifier, and I’m considering installing a ventilated baseboard + insulating the thermal bridge (cork or breathable thin lining). If you have any decor/architecture feedback to keep a light style while improving ventilation, I’m all ears!

And above all, how to remove mold from a mattress without damaging it or leaving spores?

What I’ve done/plan to do (let me know if it’s okay):

• Thoroughly vacuum (upholstery brush), then a 70° alcohol + water solution (1:1) dabbing, do not soak.

• Light white vinegar on remaining spots, then sprinkle with baking soda, let it sit, vacuum.

• Intense drying: outdoors/sun or near a gentle heat source + lift the bed frame (well-ventilated slats).

• Breathable anti-dust mite cover afterwards.