Why is my upstairs wall wet

This can be caused by cold bridging or dampness within the walls. Basically the affected areas are colder than the rest of the wall creating a dewpoint on the walls where the moisture from the ambient air within your property condenses more readily than the higher temerature surroundings.

Why is my wall wet on the inside?

What causes condensation? Condensation occurs when hot, moist air hits cold, dry air. This meeting causes water droplets to form on the cold surfaces (like your walls). This kind of moisture is what you’ll find on the bathroom walls after a super-hot shower.

How do I stop moisture in my walls?

1. How to prevent moisture in walls?
2. Ventilate your home properly.
3. Improve your insulation.
4. Install exhaust fans.
5. Get a dehumidifier.
6. Keep control of mold growth.
7. Take care of all the leaks.
8. Install wide windows.