Can I paint over a bathroom wall that has a water stain or must I treat it with something first?

My shower was leaking recently and has stained the paintwork on the wall. A friend says I need to treat it first, I think with EPS, before I can paint it again. It seems EPS smells toxic and I'm not keen to use it. So two questions, does the wall need to be treated before applying new paint? And if so what can I treat it with besides EPS?Can I paint over a bathroom wall that has a water stain or must I treat it with something first?
First, when you have water stains, they're really actually mildew/mold stains. If you don't kill the mold and it's spores, it will continue to eat through the next layer of whatever you chose to put onto it, whether primer or paint. It sees these coatings as food. If you don't treat these first, you'll simply be feeding the organism and it will grow.





To deal with the water issue you need to find out what it's coming from. If it's a leak from outside, fix it or it will keep happening. If it's from condensation from inside the bathroom, you need to install a better bathroom fan to get that moist air out of the room.





Now that you've dealt with where the water is coming from, it's time to kill the mildew. The only thing that will do this is chlorine bleach. Yes, it stinks. But it's really the only thing you can use. I would either spray it on with a garden spray and let it sit for a few minutes, then rinse it off with clean water. Or you can apply it with a sponge, let it sit for a few minutes, and then rinse with clean water. The important part is to let it sit for a while to have time to kill all those spores. Use a mask, open the windows, turn on fans...whatever you have to do. But yes, it must be a chlorine bleach.





After you've done this, you'll need to let it dry for a while. After it's dry, you MUST apply primer to the stained areas. Water stains are notorious for bleeding through, even after the mold/mildew has been treated. I usually recommend a white pigmented shellac, if you can find it. If not, use a primer specifically designed for this type of use. Ask at your local paint shop which primer they recommend for blocking water stains. They're usually going to be the people in town with the best information. Avoid ';big box'; places and stick to actual paint stores.





Did you mean TSP instead of ESP? TSP is trisodium phosphate and is just a general cleanser. It will do NOTHING to kill the mold/mildew and its spores. If you only use TSP the stains will bleed through whatever coating you apply. You really must use bleach, full strength, to eliminate the issue.





Good luck! This is an issue that is definitely fixable. It's just kind of smelly when you do it correctly. I just cannot stress enough how important it is to use chlorine bleach and a good primer, though.Can I paint over a bathroom wall that has a water stain or must I treat it with something first?
...sort of...


if there's mold, you can wash it off with a detergent eg sugarsoap...


..but as long as there is no existing damp in the wall, you can just seal the stain with an oil based sealer, or just undercoat would do. if you are using an oil based paint anyway - like eggshell, just a little touch up first will be fine!
The best bet, if you want something none toxic is PVA glue, you can buy this from most diy shops. You can mix it with water to help seal the wall before you paint it. I've used it to seal a bathroom wall and a plaster surfaces too. It's a brilliant medium that can be used for all sorts of purposes such as preparing for wallpapering. :)
Wellllllll, you could paint over the stain directly... but a) not all the paint will adhere to the wall, and b) the stain will bleed through whatever paint does adhere to the wall.





So YES, you MUST prime the stained area with a stain-blocking primer/sealer before you paint it; what you need is KILZ.





You can find KILZ in any home improvement/renovation/paint store.





From the KILZ web site: KILZ 2 Latex primer or KILZ Premium primer can be used on light water stains, but KILZ Original primer or KILZ Odorless primer should be used on medium/heavy stains to acheive maximum stain blocking. When in doubt, use KILZ Original primer or KILZ Odorless primer.





KILZ is pretty toxic and the fumes of some of the formulas can be pretty horrid... but that's the price you pay to cover rather than replace.





Before applying KILZ, open any windows you may have in the bath, turn on all the lights and the exhaust fan, if you have one... I use a paper mask just to keep the worst of the smell outta my nostrils, but you may not need to. You'll also want to wear a pair of disposable latex gloves and make sure you don't splatter the KILZ on yourself or any surface other than the wall you're priming.





Once the wall is primed, bring a box or floor fan into the bath (but don't direct the fan to blow on the wall... you don't want dust or particles getting into, and drying in, the primer) and close the door behind you until the KILZ dries. How long this'll be depends on which KILZ you're applying and the room's temperature/humidity.





Hope this helps,


TX Griff
As long as the wall is dry you can gloss paint over the stain.





Or (as long as the wall is dry) you can cover the stain with a solution of school glue diluted with water,


then when that has dried paint it what ever colour you wish
You should treat it with(Kilzs)stain cover up white paint.If you don't it will probebly soak through.