Mold and dry rot in bathroom


Old 12-27-12, 12:45 PM
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Mold and dry rot in bathroom

I pulled out my shower/tub, which was not sealed well when we purchased the house. Sure enough there was mold on the drywall (removed it). Then I found mold and dry rot in the studs and base plate, a little on the subfloor and 1 of the floor joists. I'm still in the process of verifying that the leaky shower is the only source of moisture (suspecting the toilet, too), but in the meantime I'm planning how to repair the damage. I plan on replacing the studs, base plate and subfloor, but I'm wondering if I can get away with killing the mold on the floor joist and sistering new wood to it as I don't want to go through the effort of replacing it.

Note: This all has to be done to CA building code as I'm getting a permit. I don't know too much about codes yet, but I'm going to find out more info.

1) Will the mold/dry rot spread to the new wood if I eliminate the source of the moisture?

2) After I kill the mold, can/should I seal that portion of the wood somehow to prevent any moisture from penetrating in the future and allowing the mold to grow?

Thanks for your help!
Old 12-27-12, 03:03 PM
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Definitely not an expert on mold, but once it is growing on wood, it cannot effectively be killed. They essentially cleans it up (kill what is on the surface) and then seal the wood with something special. Foster is one I see mentioned frequently.

But don't panic, mold is everywhere anyway. Eliminate the moisture and or food (wood) and it will not grow. In your case, the wood is necessary but moisture is not.

Some of the pros will be along with the best repair process.

Old 12-28-12, 01:55 PM
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I would mix bleach & water in a heavy duty pump spray bottle & shoot it, at all the mold. I don't see why that won't work.
Old 12-28-12, 02:26 PM
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I had this problem when we bought a forty year old condo. everyone in the house stayed sick and had a cough. 8 months later during a bathroom remodel, when i pulled the shower out i was amazed at the amount of mold and mildew plus no insulation on an exterior wall. we sprayed everything down with a heavy bleach solution and let it air dry, did it again the next day and on the third day the mold had turned white. we wiped down the studs and painted them with KILZ. Never had any problems after that. Other contractors have said this is a good solution as long as you don't rush and cover the walls while they are still wet.
Old 02-04-13, 01:25 PM
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Have a similar situation in daughters bathroom. She never uses exhaust fan and showers for what seems like hours. Have begun to see black spots on the paint above the shower. How do I remedy the spots and then repair over them? Thanks
Old 02-04-13, 02:54 PM
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I'd clean the ceiling with a bleach/detergent solution [rinse well] and then paint the ceiling [or whole bath rm] with a good bath rm paint. Latex enamel is bare minimum for a bath w/shower. A bath paint has extra mildewcide and is formulated for the harsher environment of the shower. If you are just painting the ceiling I'd recommend Zinnser's PermaWhite, otherwise there are several brands on the market that can be tinted.
Old 02-04-13, 04:30 PM
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In addition you could replace the existing exhaust fan with a model that operates from a built-in humidistat. It will start when the humidity rises and not stop until it drops. Teach that girl a lesson!
Old 02-05-13, 12:34 AM
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you could replace the existing exhaust fan with a model that operates from a built-in humidistat.
What a great idea! Many of us install those just so we don't have to guess at the correct amount of time, or have to decide whether to leave the fan running when we're going out.

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