[MontrealMitch]

Hi everyone,

I've been going a bit crazy trying to get to the bottom of what appears to be ongoing moisture-related wall damage - yet, when I use my moisture metre on the Wall setting, there's no indication of any moisture at all. BUT if I switch it to the Masonry setting, the trouble areas are reading up to 6% (and 0-1% in nearby areas on the same wall).

The wall in question is so thin you could drive a nail into it and there's virtually no resistance after it breaks the surface, so this is definitely not the kind of wall the Masonry setting is normally meant to be used on. I presume the fact that it's sensing anything is still something to be taken seriously? Or, does the fact that the Wall setting shows no indications of moisture over-rule that?

This begs the question, how best to use a non-penetrating moisture metre in these situations? Also, what's a normal moisture reading in concrete or brick interior walls (I ask because in other areas, on thick, solid walls that we believe to be concrete, I'm getting readings in places as high as 22% using the metre's Masonry setting).

The moisture metre I'm using is a General MMD7NP.

I'm totally clueless about this kind of thing - just bought the metre a few weeks ago - so any input would be super appreciated.

 

[Oso954]

The wall setting is not for a wall, it is short for drywall. If you are using it on some type of hardboard product, it's not the right setting.

Don't get hung up on the percentage readings. The mfg doesn't have any accuracy standard for them. They are only for comparative purposes. In other words, test a known "dry" or non problem area of the material, then test the suspected trouble spots and compare the relative readings.

 

[MontrealMitch]

Ah, thanks! Which setting would be ideal to use on hardboard materials, between Wall, Masonry, Softwood and Hardwood? On Wall, the reader stays at 0 on both the trouble area and definite dry areas. The Masonry setting, I'd imagine, would be wrong to use on hardboard, but using it, I'm getting 5-6% in the area that's got a small bulge.

 

[Oso954]

You need to identify the hardboard and learn about adhesives or surface treatments used, if any. There are many different hardboards out there with a lot of different properties.

Some will give you good readings because they are compressed wood. Others, you are trying to read the moisture thru epoxy or similar product. It's like trying to moisture read the moisture content of MDF from the topside when it's a Formica counter top.

 

[Bud9051]

Hi Mitch,
Can you tell us what the actual problem is that you think a moisture meter is necessary?

Many moisture problems are diagnosed without meters. Is this a basement wall?

In many cases the moisture passing through a wall will be evaporating before it reaches the surface. Example would be the many home owners who describe their basement floors as very dry, In reality, the surface is dry, but there is moisture passing through. Put down a piece of plastic or store some boxes down there and the moisture accumulates and becomes a real problem. Same thing happens with walls.

Bud

 

[MontrealMitch]

Absolutely. There's been an area at the upper-right of my kitchen entry way where a small bulge appeared a year ago. This bulge has grown very gradually and, weirdly, there are times when it's solid to the touch, and other times where it's just slightly soft. The other day, it was soft enough that I was able to push against it and almost smooth it back against the wall. Here's a photo of how that area looks now.

http://postimg.org/image/rwq02a8t7/

 

[MontrealMitch]

There's an air vent above the door, used alternately for forced air heating in the winter and air conditioning in the summer, and I'd initially thought they may be related, but now I'm not sure, as the bulge grew even during period when there was no heating or air conditioning being used.

Here's a photo that shows the proximity of the air vent to the trouble area.

The link didn't seem to appear, so here's the direct url to the image - http://postimg.org/image/o9smf6u57/dfa695af/

 

[MontrealMitch]

At the same time, the moulding around the entry way is warping in strange ways, that I'd initially presumed to be related to building movement (this place was built in the late '30s or early '40s), but the way it's been progressing over just a few months, I'm not sure that's the case.

Here are two examples of the warping:

http://postimg.org/image/u00vtbpjv/

http://postimg.org/image/6e0o757a3/

 

[MontrealMitch]

To make matters even stranger, on an altogether different wall of the kitchen, above the other entry way, a subtle warpage line has formed above the door. It's so subtle that it doesn't photograph well. The area's on a different wall from where the air vent is, which only adds to the weirdness and worry of this all.

I should also mention, there has been similar moulding damage taking place in other areas of the home, but without visible wall damage around them (which again initially had me thinking it was due to building movement - perhaps it is?).

 

[Bud9051]

I'm not seeing a solution, but let's review the sources of moisture and house movement.
Moisture:
1. Rain and one or more leaks, seems unlikely.
2. Humidity from the outside leaking into the home and hitting a cooler surface reaching the dew point. Primarily a summer ac issue.
3. Humidity inside the house either condensing on or around the ducts or simply varying summer to winter causing movement in the structure.
4. Basement or crawlspaces can introduce gallons of water per day even when they look dry, especially a dirt floor in a crawlspace. That moisture moves up through the house.
5. Leaky pipes.

How long have you lived here? Were there possible problems from an earlier time that were quickly painted over and left for you?

Do you have a humidity gauge to monitor RH in various parts of the home. Also record the temperature with any RH reading.

Bud

 

[MontrealMitch]

Thanks, Bud. I've been living here 2003 (it's a lower duplex, wood frame structure, stone exterior). We had some humidity issues last year but its been under control since around September. Current RH is 48% and it's 24 degrees Celsius outdoors.

I'd wondered if it could be leaky pipes, or even possibly a leaky washing machine connection upstairs, but would the moisture be showing up in such tightly isolated places on the wall?

With my moisture sensor on the Masonry setting, it will go to 5-6% in the bulged area on the wall, and then drop immediately to 0-1% an inch away, sometimes 2%. If it was a leak of some sort, wouldn't it likely saturate wider and lower after some time?

Having said that the fact that the bulge area sometimes goes from being rock solid to slightly malleable must mean some kind of intermittent moisture source?

 

[Bud9051]

I bought a moisture meter years ago with my collection of energy auditor tools and it is sitting where it has been for a long time, in my cabinet. Same problem you are having, I didn't have enough experience with mine to understand what it was saying. My infrared camera has taken up the slack for identifying moisture except if someone wants to install a wood floor.

With a remote RH gauge and temp reading at the same location you can track the direction the moisture may be coming from. I use the link below to normalize my temp and RH readings so I can compare them.

Humidity issues usually go away all by themselves in the winter and return in spring. That 24° C with an RH of 48%, was that inside or outside?

Do you have any access to the any space above your ceiling where you could take a RH/temp reading?

I've tracked down a couple of very slow leaks, slow enough that they didn't flow far from the source.

If your 48% RH is inside, are you running ac? That would be a bit high.
Bud
http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html

 

[MontrealMitch]

Thanks, Bud. The 48% RH is inside, with AC cooling the home to 21.5 Celsius (it's 24-ish outside, was 28 earlier). During the winter, Rh drops crazy low, down to the 20% range, because my place is heated with forced air electric heat.

I wouldn't have any easy way to get to the space above the ceiling without cutting right into it, unfortunately. The issue continued getting worse over the winter, though, so it's unlikely that it would be related to condensation, I think.

I'm very tempted to buy an infrared or thermal camera, but they're so expensive. Which one are you using?

 

[Bud9051]

I have an older FLIR B-Cam, it was $10,000 when I bought it years ago, but they have come way down. BUT, today you can rent them at a reasonable price.

But, cutting a hole in the area where you see the damage isn't out of the question, Drywall that gets soft is damaged even if it hardens up. And a big issue is, if there is moisture up there there could be mold. They also make inspection cameras that can fit through a 1/2" or smaller hole to let you look around.

There are condensation issues during winter but they are usually in different places.

BTW, you said "During the winter, Rh drops crazy low, down to the 20% range, because my place is heated with forced air electric heat" old myth. What really happens is an exchange of air from outside to inside. Homes typically exchange 1/3 of their volume every HOUR. When the forced hot air is running that exchange rate increases, thus dryer air.

Bud

 

[MontrealMitch]

Thanks. I was looking at a FLIR E4, which can be had for $1200 on Amazon Canada. Are they reasonably easy to use / understand if in the hands of a complete newbie? It's a lot of money, but it does seem like a valuable too for a home-owner to have. Having said that, I'm going to look around to see if there are rentals in Montreal.

I'm terrified of a possible mould issue eventually happening in my kitchen area because of this, if the dampness is consistent and never drying. I'm hoping that's not the case.

Thanks for the info about winter air change and its relation to indoor RH!

 

[Bud9051]

An expensive toy which my wife reminds of with her looks. That price seems high:
http://store.flir.com/product/e4-infrared-camera-engineering-special/ex-series-infrared-cameras but I'm not familiar with anything new. Do check for a rental and maybe that will push you one way or the other. Note, the energy auditing market is saturated so many would-be auditors are selling their barely used equipment.

As for ease of use, most are. As for interpreting what you see, they only see heat, not moisture. But, wherever there is moisture there is evaporation which gives us the cool reading and they are extremely sensitive. If a cat walks across a kitchen floor you can see the tracks. If there are moisture issues up there you should see a colder indication. Many videos I'm sure.

Bud

 

[MontrealMitch]

Thanks for that. I wonder how effective the Flir One is compared to the E4. It's significantly more affordable, of course, and using the iPhone 6 screen, the screen would be larger. E4 definitely seems to outclass it in numerous departments, but for the sheet use of leak searching, I wonder if it could be enough thermal imaging power for the job?

 

[Bud9051]

I just briefly reviewed the specs on the E4 and as expected to can capture IR images and visual images simultaneously, very helpful. I've read two opinions from people who purchased the low cost Flir and neither was impressed. One was an energy auditor and he was not impressed. The other was a home owner and he also was not impressed but it served his purposes and that may be all you are looking for.

Of course I'm already hooked so if I had to replace mine I would be looking for one of those lightly used cameras at a bargain.

Bud

 

[MontrealMitch]

Incredibly, the Flir One can capture IR and visual images simultaneously as well. I've no doubt that the more elaborate units would be better equipment, but if the Flir One could be effective at isolating a possible slow leak, that's all I'd be needing it for. For this sole purpose, do you see any benefit to a more expensive unit like that E4?

 

[Bud9051]

OK, I did some searching and here is a link on this forum that may help. Too long to re-read so have at it.

Basically, you can't get hurt by starting with a new FLIR one. With today's resale avenues, when you are done you can recover most of your investment and probably be ahead, considering the times you can use it, as opposed to a rental.

The only requirement I would suggest would be to report here your experience.
http://www.diychatroom.com/f2/i-love-my-flir-one-363905/

Bud