Bathroom Paint Help

Good morning. Just looking for some clarification / help on some paint issues in the bathroom.

We started out with our bathroom walls being a very very deep blue. I used the Zinser 123 primer. The blue continued to show through the Zinser, so I decided to step it up to a primer more suited for darker colors. After placing a coat of the new primer ovre the Zinser, I started to notice that the paint in and around the showers was turning "brownish" and looked like it had water marks running down the walls. My guess is that the second primer wasn't meant to handle the moisture.

My question to the forum, when I paint the bathroom, with paint meant to handle the moisture, will this seal in the other primer and eliminate the brownish that is showing up? Or do I need to put another coat of Zinser over the other primer, then paint?

 

You shouldn't need any more primer. I suspect what is happening is steam from the shower is getting on the flat primer and causing the streaks. It would do the same thing if the bath rm was painted with flat latex paint.

 

Thanks marksr! That's what I figured.

So I should be able to just put the new paint on and it should eliminate the streaks? Of course, that is paint made FOR the bathroom.

 

Ya, I'd be suprised if the streaks bled thru the top coat. A kitchen and bath enamel is best but most any latex enamel is ok.

 

A general rule-of-thumb is this... its not ready for paint if something is bleeding through it.

 

The brownish substance is "surfactant" which leached out when the primer got wet from the humidity of the shower etc..

All latex paints (as a rule) are subject to surfactant leaching (because they all have surfactant in them, and latex paint is porous).

Surfactant is a soap-like water soluble substance, it will wash off with a damp sponge.

Wash the surfactant off before painting.

You don't need to re-prime. (123 Bullseye will also leach out surfactant too).

If you want a surfactant free paint job in the bathroom, you may need to:
1. Vent the bathroom to prevent humidity build up on the walls
2. Use an oil based paint which will not leach out surfactant

Even the latex bathroom paints will leach surfactant, some less than others perhaps.

Surfactant is more noticeable on dark colors. It eventually leaches out less and less as the paint cures fully. You may have to wipe it off in the early stages of paint curing from time to time with a sponge. Use care with wiping it off the finish paint film, wait the prescribed period (see paint can label) before wiping it down, and don't press hard on the paint with the sponge because latex wall paints will burnish (shine) easily when rubbed. (this is the reason for using a sponge instead of a rag - to lessen the chance of burnishing)

On exteriors, surfactant will leach out of a new latex paint film and then eventually with additional rain etc... finally all leach out and weather off. Interiors can be a little different than exteriors.

 

As a side note, it is expected that you would still see your original color underneath the 123. Most primers exist merely to seal and provide a stable surface for the topcoat to adhere to. One of the ways they do this is by skimping on the pigment. It is usually the job of the topcoat to hide, not the primer; so a blotchy look after priming is normal, and no reason to apply more primer.

The sole exception to this is if you are trying to do a Light->Dark color change. In that case, there are specific hiding primers on the market for this use, which are usually tinted grey.

In case you were curious, the surfactants that are likely leaching through your coating are what keep the pigments from separating out of the coating while you are attempting to apply it to the wall.

SirWired

 

Clarification:

If you want a surfactant free paint job in the bathroom, you may need to:

1. Vent the bathroom to prevent humidity build up on the walls (if using latex)

OR

2. Use an oil based paint which will not leach out surfactant

Side Note: A draw back with using oil is while they are not subject to surfactant leaching, they are more prone to mildew growth. This can be countered by again - venting during showers etc... and/or by adding a commercial midewcide additive to the paint.

 

I agree if could be the ventillation. If you have an older fan you might want to have an electrician (or investigating it yourself through fan manufacturers) look at it and tell you how much power you need for that size room. I've seen some bathrooms where the fans just weren't powerful enough to handle taking the moisture out.