Paint problem

[gurbian]

Hi everybody
I fixing some sheets of plywood up into the roof of my garage, so thought i'd try and seal them before painting just in case the roof leaked and they got a bit wet. So i coated them with some ronseal fence paint and then some diluted emulsion. When these dryed i gave them another 2 coats of emulsion. But when i now rub them just with a wet finger the paints comes off!
Ant suggestions

 

[andywhy]

i'm guessing the fence paint is repelling the emulsion (thinking it's rain!)

 

[gurbian]

I was thinking along those lines as well. The thing is, is that i had the same problem on an interior wall a few years ago. I've just been doing some searching and it sounds like it could possibly be something called 'chalking', but what from what i've read this normally happens when interior paint is used exterior

 

[bradleydecorating]

Suggest you try to get the whole lot off down to the point where neither white spirit nor water will shift any more, allow to dry off, then waterpoof it with oil based undercoat followed by oil based gloss/eggshell. Then you can put emulsion on it if you particularly want that finish, or just leave it eggshell.