Walls and Ceilings - Brown spots?!?!

So I bought an old duplex... first time home owner, first time landlord. The house has plaster walls, in various conditions. Some show obvious areas of repair, other spots are very soft. I am replacing the soft spots with drywall, which is fun doing it yourself for the first time.

On the areas which are solid, but uneven texture due to patching and such, we have decided to put on a faux finish... in order to cover some smaller cracks, and make everything look consistent. Not knowing what kind of paint we were dealing with, we primed the walls, and then put joint compound on to give the texture. We finished that last night, and haven't started painting.

It rained yesterday, and last night. This morning I go in to look at the awesome job we did... only to see brown spots all over the walls. Most on exterior walls, but on some interior walls too. My first reaction says that the roof has a leak... and these are water spots.

But... its rained before, and no spots. Could it be that the wall breathed before, letting moisture out... and now that it has the primer, and compound on it, thats causing it? Its not everywhere, so its not a reaction of the walls/primer/compound... and its on some interior walls. Mostly its on the upper parts of the walls, which makes me think even more its water.

Thoughts? I really don't want it to be a leak, please tell me that it was just my eyes this morning when I got up.

-Russ

Brown spots here as well!! 30 yr old home, 1st floor living room had old wood paneling in it. removed paneling to reveal old sheetrock which was tanned like an old newspaper but in decent shape. not being the most skilled when it comes to taping & jointing we decided to use to lightweight joint compound to give the walls an old world Venetian look.

well, we came down this morning to check out the awesome job we did last night only to find a bunch of brown spots all over the wall!! the two walls we did were an exterior & one shared w/the garage. the paneling had been down for a month before we got around to working on the walls so we know there are no active leaks & there weren't any obvious signs of previous water issues. plus it's a 1st story room with no plumbing above it or in it so we're very confused as to what this might be and what our options to cure are. the thought of tearing down & putting up new sheet rock is just heartwrenching.

any assistance would be most appreciated.

anyone? anyone? Bueller???

It sounds like the "brown newspaper-like" stains have just transferred to the surface of your joint compound. Water soluble stains will do that as the wet mud dries. You'll need to apply a stain blocking primer to the wall. I'd suggest a shellac based primer like B-I-N made by Zinsser. It will cover almost anything.

Zinsser's website has a nice DIY product selector for their primers which helps you select the right product for the stain you are trying to cover. If you look at it, you'll find that some of their products will not hide every stain. The B-I-N will.

More than likely an oil base primer will seal the stains. When in doubt, a pigmented shellac [like BIN] is the best sealer.... but it also has the most potent odor :eek: