Paint blistering under very specific circumstances. Any idea why?

[pieceofmind]

I painted the house last summer. Over the winter the paint has blistered in places, but only upstairs and only on the outer walls (or within a few cm of the outer walls) and only up near the ceiling.

In those places where the paint has fallen off after blistering, the old paint which I had painted directly over (and which I also painted - around about 8 years ago) is still perfectly ok and feels dry to the touch.

It looks hideous and is making a mess so I'm going to have to sort it, but I want to ensure it doesn't reoccur, hence my asking the good folks here for their thoughts. Cheers al.

 

[Wayners]

Condescension problem I guess.
Buy a humidity sensor to monitor.
Fix condensation by airing house or getting dehumidifier.
Thermal liner will help stop surface condensation and use correct paints that resist condensation.

 

[pieceofmind]

Hi. Thanks. I'll order a sensor now. Over winter I occasionally had to wipe maybe the bottom 6th of the bedroom windows first thing in the morning because condensation was present. Could that much be enough to cause the issues described?

 

[Wayners]

Yes. Moisture dumps on the cold glass.
When it was freezing in December around tea time, I opened all the bedroom Windows for 15mins which reduced condensation overnight.
Called airing house. Look it up.

The monitor will show you what's happening. Common problem