What would happen if you painted latex paint over preexisting oil paint without primer?

It wouldn't adhere very well. You're better off with a good primer or sticking with oil paint.

depends on the condition of the oil based.

It make feel like it's dried on just fine, but what you have is a loose coating. It will not stick and eventually will either bubble or simply break loose.

Was this inside or out?

If the oil based coat was in poor condition the latex will make that come off too. Now you're running into the possibility of lead dust.

If you only did one room, my advise is to take the paint off and to it again with primer. It's going to be alot of work, but you'll be happier.

If you did the outside, I'd wait and see what happens. You might get lucky and most of it could stick a year or maybe even 2.

You need to confirm this at your local paint store because it's been years since I've actually done it: If I recall correctly, whenever I've had to seal a damaged wall, whether it was banged and exposed metal wall corners or patched wallboard, I've used an oil base primer (in all the rooms) -- just because it's the best and I knew it would stick well to the wall and to any type of paint -- either water or oil based. Listen to uncle bob (above)

You will be fine the general rule of thumb is you can paint latex over oil but not oil over latex because the latex will move which will crack the oil. Just make sure your walls are in good condition and have at it

the latex will not bond with the oil paint and any place that it can peel, it will.... like when you take off the masking tape....a too-heavy coat or a couple of coats that are not totally dried will even 'slump' down a wall and look like my turkey neck!....

you really don't want to find out.... use the primer!

You run the risk of the paint peeling. It probably won't happen, but why take the chance? Primer's cheap insurance. Hope this helps.

Its gonna bubble and peel.You need to sand it first, just lightly nothing major, then prime, then paint. Be sure the walls are clean before each coat.

You should be ok.

http://www.target.com/Fabric-Task-Chair-Purple/dp/...