Why did my newly applied paint run and not adhere to the wall?

Question

I painted my bathroom, then woke up the next morning to find that half the paint from the top of the window wall had dripped back off again, leaving really big tear marks down the wall.

The bathroom was originally painted the blue colour. I sanded, applied sugar soap and waited till it dried, and just applied white paint as the color I am putting on is lighter. There was no silicone or anything. I just think the wall is that damp. The paint covered really well so I was all set to add the colour on top the next day. The wall gets damp overnight as do the window, toilet etc. from condensation I think.

I have really limited money and was advised to use PVA on the wall to seal it, then paint over that once dry to get the paint to stick.

Has anyone tried this and did it work?

Answer 1

My guess would be that you didn't prime and that you tried to paint over oil paint with a latex paint or some incompatible combination of paints like that.

You should figure out what type of paint was used for the original coat and purchase a suitable primer to go on top, and then apply your new color. If you really aren't sure, someone at a paint store can recommend a primer that is suitable for a range of scenarios.

Based on the picture I would probably avoid a paint-primer combination product.

Primer is typically pretty cheap so aside from the additional labor and time, it should not add considerable costs to your project.

Answer 2

Let me ask you a question how humid was it the day and that night and how warm in the house. Very Hi humidity and temp can cause this to happen as heat rises and hi heat and hi humidity can cause this. I have been painting for 40 years and have had this happen to me. Since it was in your bathroom a small closed in space the humidity level if it was High outside was even higher in your bathroom. Also if it was cold out as I see it was in Feb and it looks like older home and the paint did not run anywhere else , the temp and humidity was the issue. Either cold or hot and humidity​ can cause this problem