Orlando, FL · Member since 2009 · 2k+ posts · 282 votes
In one of my properties there is about 2 to 3 square feet of of mold on the base boards and the drywall just above the baseboards behind the vanity, under the sink's plumbing.
The visible parts of the plumbing are not leaking. I haven't seen evidence of mold anywhere else in the property.
I would like to fix this myself and avoid using remediation people if at all possible.
1) Is the best course of action just to cut out those parts of the drywall/board that have it, so I don't risk contaminating other areas, rather than trying to scrub it off? (and then replace that drywall)
2) Since there is no visible leak, does that mean that there must be a leak somwhere behind the wall? I don't see any holes it the drywall where mold could have spread from the inside of the wall.
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
Only real way to tell what needs to be done is to start removing drywall and see what you find. If it's not behind the drywall it could have come from sink water running down the back of the vanity due to improper sealing over the years.
Whether you do it yourself, or need someone to come in due to a bigger problem, the drywall should come off.
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
Only real way to tell what needs to be done is to start removing drywall and see what you find. If it's not behind the drywall it could have come from sink water running down the back of the vanity due to improper sealing over the years.
Whether you do it yourself, or need someone to come in due to a bigger problem, the drywall should come off.
Property Manager · DeLand FL · Member since 2012 · 860 posts · 243 votes
13y
I would agree with Dylan that you need to remove the affected drywall and take it from there.
There must be some sort of leak somewhere because if it was a ventilation issue with moisture you would have the growth on the ceiling, with it being the lower section of wall and baseboard would seem a pipe is dripping and seeping into the drywall and beneath the baseboard.
Real Estate Investor · Millbrook, AL · Member since 2008 · 68 posts · 34 votes
13y
With experience you can tell if it is coming from the inside of the wall or not.
If it is from the outside and there is no current evidence of a leak, then it is because mold has roots that are multiple times greater than what the naked eye can see and it was just painted over in the past and has come back. Painting over it again will delay the mold for about one year but the roots will continue growing.
Because cutting it out and replacing everything moldy can become a can of worms, I prefer to treat it with the same stuff I put in my swimming pool. It is copper based and one quart will treat 40,000 gallons so just dilute it in any old spray bottle about 50/50 with water and spray the affected areas, and let it dry. Then you can paint over it and wait and see. So far I have not had any recuring problems with this approach.
If you have ever used a wood preservative product that was green, it is because of the copper content. Copper prevents and kills all different kinds of mold and algae. That's why copper tin roofs can last over one hundred years.
If it is coming from inside the wall, it is probably from the tee joint immediately behind where the drain goes in the wall. The threads on the old galvanized fittings are thinner than the pipe wall and are prone to rusting out. This can be fixed with a rubber patch glued with silicone and a hose clamp. A plumber will want to cut everything out and "do it right" but since this is not under pressure, like a hot or cold water line, it will probably outlast you. I have never had a recall in 30 years, so far.
I have been sued for mold in the past so I now have a comprehensive mold addendum to my rental agreement. You would not believe the story behind that one, so I won't go into it here.
Fix the hole in the wall with flashing glued down with liquid nails. You don't need multiple coats and it can be painted right away. You can cut it with sissors to shape it around the pipes and stuff. None of it shows because it is behind the vanity.
The entire project will take you about two hours and cost around $50.00 tops.
Or you can bring in the plumber and carpenter and a has-mat team for around $3000.00
Landlord · Seattle, WA · Member since 2010 · 3k+ posts · 1k+ votes
13y
Sounds quite likely that you have a leak of some kind inside the wall. You won't know where exactly until you open up the wall unless by chance you or a good friend of yours has a good infrared camera that can help you see what is going on.
Orlando, FL · Member since 2009 · 2k+ posts · 282 votes
13y
Originally posted by Dylan Long:
If it's not behind the drywall it could have come from sink water running down the back of the vanity due to improper sealing over the years.
Dylan Long If this were the case wouldn't I see water running down down the wall behind the vanity when I turn the sink on? I don't see any dripping or leaks when I do that.
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
Originally posted by Bienes Raices:
Originally posted by Dylan Long:
If it's not behind the drywall it could have come from sink water running down the back of the vanity due to improper sealing over the years.
Dylan Long If this were the case wouldn't I see water running down down the wall behind the vanity when I turn the sink on? I don't see any dripping or leaks when I do that.
I was thinking more of the case in which there was water pooled due to an overflow that caused mold to take hold. Yes, generally you'd see an external ongoing leak.
The most likely culprit is a small leak inside the wall, in which case you'll need to open it up a bit and address the issue. To fix it right, you'll want to keep going until you don't find mold anymore.
I disagree with Christian's method for fixing it, but that's mainly because I'd be comfortable "doing it right" without a plumber. I am especially sensitive to mold situations as my GF of 5 years has bad asthma, and mold can be a huge contributor to breathing issues. I wouldn't want to put someone in a home that I wasn't comfortable living in (with her) myself.
If it were me, I'd pull the vanity, cut the drywall out in a 16"x24" patch (between studs) along where the plumbing goes, and explore.
Replacing a panel of drywall that size takes just about as much time as doing one 1/3 that size, so why not get a better view? I'd also replace W/ moisture/mold resistant drywall, rather than just use flashing and glue. But again, this is my preference because I can do it myself, which saves on the cost and time of using a contractor.
Real Estate Investor · Audubon, PA · Member since 2009 · 13k+ posts · 8k+ votes
13y
Originally posted by Bienes Raices:
Originally posted by Dylan Long:
If it's not behind the drywall it could have come from sink water running down the back of the vanity due to improper sealing over the years.
Dylan Long If this were the case wouldn't I see water running down down the wall behind the vanity when I turn the sink on? I don't see any dripping or leaks when I do that.
Bienes Raices - you aren't a tenant! I would start by asking you: "What is your tenant doing at the sink, that might be causing water to run down the back of the sink?"
And bathroom sinks are very easy to get to overflow, especially many of these newer cheaper units that don't have an overflow opening, or ones that have an overflow opening that's too tiny to handle the water flow from the faucet. And if water is getting on top of the sink, water could be leaking through the faucet pipe openings in the top (assuming the gasket or plumber putty isn't watertight enough or missing).
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
Originally posted by Steve Babiak:
Originally posted by Bienes Raices:
Originally posted by Dylan Long:
If it's not behind the drywall it could have come from sink water running down the back of the vanity due to improper sealing over the years.
Dylan Long If this were the case wouldn't I see water running down down the wall behind the vanity when I turn the sink on? I don't see any dripping or leaks when I do that.
Bienes Raices - you aren't a tenant! I would start by asking you: "What is your tenant doing at the sink, that might be causing water to run down the back of the sink?"
And bathroom sinks are very easy to get to overflow, especially many of these newer cheaper units that don't have an overflow opening, or ones that have an overflow opening that's too tiny to handle the water flow from the faucet. And if water is getting on top of the sink, water could be leaking through the faucet pipe openings in the top (assuming the gasket or plumber putty isn't watertight enough or missing).
Indeed. Or even if water pooled often enough on the countertop from washing hands, faces, etc, and the back of the vanity wasn't sealed, it could leak down that way too.
In any case, I'd still be pulling a bit of drywall to ensure there isn't a bigger issue, or that it hasn't spread through the drywall. But I'm paranoid and wouldn't want to hand a mold problem over to someone.
Orlando, FL · Member since 2009 · 2k+ posts · 282 votes
13y
I think I am going to remove the drywall and then try to replace the drywall and baseboard myself later to save money. Since it's going to be hidden behind a vanity it doesn't have to be a perfect job.
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
Nope, and the best way to learn is practice a bit. Black and Decker has a great book on dry-walling, with lots of pictures. Good investment for 15-16 bucks.
Orlando, FL · Member since 2009 · 2k+ posts · 282 votes
13y
One other question: if open the drywall and find mold inside the wall, what do I do? Is it time to call a remediator? Or if I fix the leak will that mold just dry and die on it's own?
Property Manager · DeLand FL · Member since 2012 · 860 posts · 243 votes
13y
Fix the leak, remove any of the drywall that is contaminated and clean the rest of the area using a product that is designed for mold removal. Repair area.
Orlando, FL · Member since 2009 · 2k+ posts · 282 votes
13y
Originally posted by David Niles:
Fix the leak, remove any of the drywall that is contaminated and clean the rest of the area using a product that is designed for mold removal. Repair area.
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
People go either way. Sometimes local code mandates green board though. A lot of people say regular drywall with a good primer and paint provides the same level of protection as green board. Green board won't help with mold though unless it's paperless.
Property Manager · DeLand FL · Member since 2012 · 860 posts · 243 votes
13y
I would probably just use regular drywall, more importantly is type of paint, minimum of satin, preferably semi gloss, flat and eggshell are no good as the mold/mildew grows easily on them.
Investor · Southeast, MI · Member since 2012 · 2k+ posts · 1k+ votes
13y
I would use greenboard. It's only a few more dollars and could give extra protection. If you get the regular drywall, it might be like jumping over a dollar to pick up a dime.
Investor · Central Valley, CA · Member since 2012 · 6k+ posts · 3k+ votes
13y
For what it's worth, the last 3 vanities I dealt with that had moisture/mold in the sink cabinet or back walls, the cause turned out not to be supply or waste pipe leaks. I learned the expensive way to check out other possible causes first. Moisture/drips coming from above, but through a poorly mounted or failing faucet will travel along to the p trap, making you think the pop up drain or p trap is leaking, when it's not. Or the water will travel along the supply lines and drip onto cabinet floor or wall, making you think the supply lines are leaking, when they are not. After recently recaulking a sink and replacing a faucet, it turns out the moisture in the cabinet was from splashing water on the counter, where it was traveling through where the counter and backslash meet. I look A LOT more closely at what's going on above now. :)
Real Estate Investor · Forest Grove, OR · Member since 2012 · 105 posts · 37 votes
13y
Originally posted by K. Marie Poe:
For what it's worth, the last 3 vanities I dealt with that had moisture/mold in the sink cabinet or back walls, the cause turned out not to be supply or waste pipe leaks. I learned the expensive way to check out other possible causes first. Moisture/drips coming from above, but through a poorly mounted or failing faucet will travel along to the p trap, making you think the pop up drain or p trap is leaking, when it's not. Or the water will travel along the supply lines and drip onto cabinet floor or wall, making you think the supply lines are leaking, when they are not. After recently recaulking a sink and replacing a faucet, it turns out the moisture in the cabinet was from splashing water on the counter, where it was traveling through where the counter and backslash meet. I look A LOT more closely at what's going on above now. :)
Thanks for pointing this out K. This was a cause I was trying to convey on page one, but perhaps poorly so :).