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Recommend a moisture meter for this?


David Meiland
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First off, I'm not a HI, I'm a GC, and occasionally I get asked to solve problems. A few months back a customer of mine bought a 1960s home. They hired a flooring contractor to remove carpeting and install hardwood.

The flooring contractor found a stained area of subfloor in a closet that backs up to a shower. My customer asked me to look at it. In the basement directly below the shower, in an area with a partly-sheetrocked ceiling, I stuck my hand in and found wet insulation. I told the owner he needed to have a plumber find the source of the leak and fix it... which he did. I also told him he needed to have all the wet insulation removed, allow the area to dry thoroughly, and then replace the insulation and sheetrock.... which he did not. What he DID do is have part of the insulation removed and replaced, and then had sheetrockers complete the lid and tape it all.

Fast forward to today: he calls again, there are ants cruising around in the basement. IMHO that means there is a source of moisture, so I went to look. Based on the description today of what was done, I suspect they accidentally left an area of wet insulation--a miscommunication occurred between owner and sheetrocker, who was charged with pulling out the wet stuff and later replacing it.

Anyway, from below there's a newly finished sheetrock ceiling, from above there's plywood subfloor awaiting flooring. I would like to find out if there are areas of remaining moisture without drilling a bunch of big handholes in the subfloor or punching them thru the lid. It occurs to me that a moisture meter with a probe might be useful. I own a Mini Ligno that I use for metering lumber, flooring, etc., but I do not own a pinless meter or one that takes a probe. If I can drill small holes thru the subfloor, and insert a probe, seems like I could first meter the fiberglass, and then the top/back of the sheetrock.

Any comments on this strategy? Recs for a meter?

FWIW the owner hired a HI in this transaction. He didn't do much careful evaluation that I could see....

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. . . I told the owner he needed to have a plumber find the source of the leak and fix it... which he did.

Unless someone removed all of the wet insulation and looked at it from below, no one really knows if the leak is fixed. What, exactly, was leaking anyway?

I also told him he needed to have all the wet insulation removed, allow the area to dry thoroughly, and then replace the insulation and sheetrock.... which he did not. What he DID do is have part of the insulation removed and replaced, and then had sheetrockers complete the lid and tape it all.

Fast forward to today: he calls again, there are ants cruising around in the basement. IMHO that means there is a source of moisture, so I went to look. Based on the description today of what was done, I suspect they accidentally left an area of wet insulation--a miscommunication occurred between owner and sheetrocker, who was charged with pulling out the wet stuff and later replacing it.

Ha! You're way too generous. The trolls just did a crummy job.

Anyway, from below there's a newly finished sheetrock ceiling, from above there's plywood subfloor awaiting flooring. I would like to find out if there are areas of remaining moisture without drilling a bunch of big handholes in the subfloor or punching them thru the lid. It occurs to me that a moisture meter with a probe might be useful. I own a Mini Ligno that I use for metering lumber, flooring, etc., but I do not own a pinless meter or one that takes a probe. If I can drill small holes thru the subfloor, and insert a probe, seems like I could first meter the fiberglass, and then the top/back of the sheetrock.

Any comments on this strategy? Recs for a meter?

Any meter you use will miss too much to make that strategy practical. I'd just pull the lid, yank all of the insulation, check the plumber's work from behind, see if I can find where the ants are nesting (if they're not just a coincidence) and then put it back together properly. It wouldn't take long, drywall's easy. Besides, it sounds like the drywall contractor owes the owner a favor anyway.

FWIW the owner hired a HI in this transaction. He didn't do much careful evaluation that I could see....

Doesn't surprise me. They're all bums.

- Jim Katen, Oregon

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For measuring moisture on the back side of ceiling drywall non-invasively, you'll need a Tramex moisture encounter plus, a surveymaster is not up to the task.

Invasively, if I was desperate, I would do as Rob would do and use the long probes with a protimeter; maybe even stick a hygrometer up thru a hole to see if the humidity is high enough to support mold growth.

What I actually have had really good success with is using a thermal imager and the Tramex with this sort of problem. If there's a leak with the tub or shower plumbing, the thermal imager will pick it up even if the back of the drywall is just being wetted.

The best thing is to do what Jim Katen said and open it up again and take a look.

Chris, Oregon

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I have it on good authority that the plumbing leak was repaired. The shower valve was the culprit. I'm assuming that any moisture is residual, but there could be a lot of it--a leaky shower valve can send water down thru the drilled holes in the bottom plate of the wall where it lands on the drywall below, and from there it travels widely, in addition to getting the top of the subfloor wet.

It does seem like the Tramex meter is the one that might work in this situation, but if I'm going to spend a thousand on something I'm just going to spend several thousand and get a thermal imager. I have frequent situations where I could use one, but I'm not going to pull the trigger until business is up a little more.

So, for now... handholes are us.

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David, don't be focused on the plumber, I have seen numerous leaks in showers that are the result of unmaintained grout, poorly installed (or not installed at all) membrane under shower seats and pans, a good one is when the drain slot on the fiberglass or acrylic shower pan lip gets caulked or grouted shut, some leak so bad that you just know it has to be the plumber.

You can start to isolate by removing the shower head, connecting a hose and discharging the water in the toilet.

Good luck

Tim

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The closet wall behind the shower was opened up and a leak found and repaired... or so I was told! Of course there could always be an ongoing leak. If I get elected to drill the handholes, one will be directly below the valve wall and one will be directly below the trap. I think that drilling several inspection holes (I usually use a 5" hole saw for holes thru drywall) and leaving them open while a dehumidifier is run will take care of it. Obviously, any area where moisture is found would reqire removal of the drywall and insulation, but it would take a dozen or more inspection holes just to verify that the moisture is gone, if it is.

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Hi David,

Everyone has given you good information so far but don't miss the forest for the trees; if there are ants nesting you've got more than just moisture - you've got rot someplace. The wood-destroying species out here are largely carpenter ants and several varieties known as moisture ants and moisture ants are attracted to rotting wood. It's possible that the plumbing isn't leaking and that the insulation did dry out and things in the ceiling are fine but that the ants are there because of something else.

It's pretty common to find them in sills and rims under bathrooms when there is loose tile in a tub or shower surround and they'll get into joists below toilets with leaking pedestal seals and leaking dishwashers. I had one house where a fellow had an unsealed pipe passing through the wall of a finished basement behind drywall attached to furring strips. Water from lawn sprinklers found its way in along the unsealed pipe, soaked into the grid of furring strips and caused them to rot. The drywall looked great on the walls of his basement but ants were everywhere. The carpeting tipped me off to the location, I found a damp area with my SM and followed it to the wall and when I scanned the wall and probed it found all that moisture. When we opened it up we found that 3/4 inch gap behind the drywall stuffed full of moisture ant frass - a crumbly brown mess that looks kind of like lava rock.

Good luck with the hunt!

ONE TEAM - ONE FIGHT!!!

Mike

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Wouldn't having the ants identified first be a good idea?

Moisture ants, as others have pointed out, very likely mean previously rotted wood and I would go along with tearing the drywall down until I found all of it.

Carpenter ants might or might not be related to the plumbing leak but will (very probably) still need to be treated.

Other "nuisance" ants in a 60's basement in the San Juans? Might be nesting inside or you might just need a penetration or two sealed. Too little to go on.

Getting a good pest control guy in there seems like a smart idea. He should, at the least, be able to identify the critters and might also be able to pinpoint the problem, or at least narrow the choices.

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All good advice, just one clarification......

The Protimeter is just fine for testing conditions like this if you have deep probes. Make your own out of thin steel rod, insulate the lengths with heat shrink tubing so only the tips are exposed, and connect the propbes to the pins on the protimeter with wires and alligator clips.

We've been testing structural members buried in masonry >12", and having excellent results. The IR folks and the Tramex folks have been coming up with no results on a lot of our jobs, and we've been able to find moisture in locations otherwise inaccessible to conventional tools.

More on point........

I'd tear the drywall off. It's just drywall. And get a bug guy to tell you what's going on with the bugs.

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One thing to keep in mind if you make your own probes for the Protimeter: per a phone conversation with GE, even if you calibrate against the built-in pins or the OEM extension probes, your results may not be accurate anywhere other than at the calibration point - readings are still useful as relative indications of moisture content, but IMO should be reported with the caveat that they may not be as accurate as absolute readings as those obtained with OEM probes.

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No one tool will do. You need a bevy of them.

Chris, Oregon

I agree completely.

I also agree with Michael's point about OEM and homemade adapations; there needs to be wide margins of interpretation applied whenever using any of these tools, especially when they've been altered from the OEM's components.

It's why I said tear out the drywall; none of the toys provide definitive analysis; they only point to where to tear out materials.

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Thanks again for all of the feedback. This is a fantastic group. You guys are making me think about what my role really is here.

They did have a pest guy come out, he did use the term "moisture ants", and he failed to propose a solution. I have a call in to him now to see if I can get his comments directly, instead of from the owner. I rarely deal with pest issues and in this case my only comment to the owner was that their presence might indicate moisture. Found out yesterday that there are carpenter ants under the refrigerator on another job that we are starting in a month. Maybe it's warm and wet under that frig.... oh great.

I'm still going to recommend that they remove sheetrock plugs and check for wet insulation throughout the floor framing, starting near the tub plumbing and working away.

The basement area in question is fairly small, accessed only by a door from the exterior, is not heated, and is completely sealed--no ventilation. It's really more of a stand-up crawl space with sheetrock on the walls and ceilings. I'm wondering if this should be vented. It was sheetrocked several weeks ago and I can still smell the mud.

The REAL rub on all of this is that I was asked initially to go over the house, read the HI's report, and price out the various repairs and corrections that he flagged. They did not hire me to do any of the work, the got a sheetrocker, a plumber, a painter, a flooring guy, and whoever else on their own. Now that the job has not been properly managed (i.e. the moisture problem was not fully remedied before the sheetrock was done) they are calling me back. I hate getting caught up in things like this. There are 2-3 HIs here and AFAIK none has a IR camera or a moisture meter of the type you guys are carrying. You really can't get a good prepurchase inspection unless you import Mike or someone else.

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You really can't get a good prepurchase inspection unless you import Mike or someone else.

That's a shame. Thanks for the compliment; I've been up there - a client had me go down the street 1/4 mile, climb into a float plane at Kenmore Air and I flew up there for an inspection. I stayed overnight at an old hotel downtown - Friday Harbor Inn or something like that - and came back the next day.

It's a nice island. Truth is, I'd love to live in a nice pastoral place like that but I can't convince the Frau, who grew up in a city of 12 million folks, to live in small town America.

Even if I could, I don't think we'd be able to survive. According to a realtor I spoke to up there, there're only about enough sales a year to support a couple of part-time inspectors that have other jobs and throwing another inspector into the mix would mean another guy making meager inspection income and working most of the time at something else.

Which begs the question, David, have the experienced inspectors up there (Those with more than two years in the business and more than 100 inspections under their belts as of June 12, 2008) begun getting their ducks in a row for licensing?

They've only got until September 1st to complete all of their requirements. If they fail to complete the licensing requirements by September 1st, they're going to need to get 120 hours of in-classroom training in a state-approved course, do 40 hours of supervised inspections with an experienced inspector and then take the National Home Inspector Exam and the Washington State Exam from the state's approved vendor, before July 1st 2010, or they'll have to stop inspecting on that date until they've completed all of those requirements.

If you know either of those guys, give 'em a friendly call and remind 'em. If they tell you they don't know anything about it, refer them here to TIJ or have them check out the Home Inspectors Licensing site on the DOL website under business licensing.

ONE TEAM - ONE FIGHT!!!

Mike

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Thanks again for all of the feedback. This is a fantastic group. You guys are making me think about what my role really is here.

They did have a pest guy come out, he did use the term "moisture ants", and he failed to propose a solution. I have a call in to him now to see if I can get his comments directly, instead of from the owner. I rarely deal with pest issues and in this case my only comment to the owner was that their presence might indicate moisture.

Not just moisture, but wet, rotting wood. The "solution" to moisture ants is to find the wet, rotting wood, remove the source of the moisture, and replace the damaged wood. There's no reason to treat the ants. They'll go away on their own. If you don't find them in the shower area, I'd start looking at the walls' lower plates.

Found out yesterday that there are carpenter ants under the refrigerator on another job that we are starting in a month. Maybe it's warm and wet under that frig.... oh great.

Probably just warm. Carpenter ants are attracted to warm spots in the house. Under the fridge is one of the top ten places to find them.

I'm still going to recommend that they remove sheetrock plugs and check for wet insulation throughout the floor framing, starting near the tub plumbing and working away.

That still seems like a hunt & peck method that might or might not show you what you need to see. With only slightly more effort, you could pull the whole lid about 12" in from the edges and all would be revealed.

The basement area in question is fairly small, accessed only by a door from the exterior, is not heated, and is completely sealed--no ventilation. It's really more of a stand-up crawl space with sheetrock on the walls and ceilings. I'm wondering if this should be vented. It was sheetrocked several weeks ago and I can still smell the mud.

Concrete or dirt on the floor? What's behind the sheetrock on the walls -- I mean the arrangement of vapor barriers & insulation?

The REAL rub on all of this is that I was asked initially to go over the house, read the HI's report, and price out the various repairs and corrections that he flagged. They did not hire me to do any of the work, the got a sheetrocker, a plumber, a painter, a flooring guy, and whoever else on their own.

Did they pay you for your time as a consultant?

Now that the job has not been properly managed (i.e. the moisture problem was not fully remedied before the sheetrock was done) they are calling me back. I hate getting caught up in things like this.

Ah, welcome to our world.

There are 2-3 HIs here and AFAIK none has a IR camera or a moisture meter of the type you guys are carrying. You really can't get a good prepurchase inspection unless you import Mike or someone else.

Sounds like a job opportunity. . .

- Jim Katen, Oregon

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