Humidity up to 70% again... ?? What am I missing?

[MamaBird]

So when I got to this house RH inside was 70% outside 80%... A-framed house sitting on a poured concrete basement... septic had not been pumped in 8 years, sits on top of a hill with marsh 250' away to the right and a running stream 400' behind the house (where's this humidity coming from?). Windows were replaced this past spring (tightening up the house), used our Flir and you can still see some infiltration around window frames (they didn't replace the sills and did not install foam around the edges). Interior walls in the house are dry and all exterior walls and basement walls/floor read damp... oh yea... they had a French drain installed on the interior perimeter of the basement 9 years ago.

So my thoughts... they are pulling water into their home foundation, into the French drain. We had the sewer pumped out and applied a water chasing sealant to the basement floor and walls, the sill plate had previously been sealed with spray foam insulation.

Added dehu's and were able to maintain the house at 40%RH. Advised they have an air exchanger installed.

We have pulled our equipment and RH went back up to 70%, outside is now 60% and 32 degrees.

Other issues in this home... odor in closet, other side of closet is bathroom tub, surround is wood planks. Mold odors in home, tested... yep it's hot, 600-8000% high spore counts. Get behind closet, it was not the obvious wooden tub surround... it was mice infestation in the crawl spaces + wet fiberglass insulation from roof leaking because there was never ice dam blocker installed under roofing shingles (ugh!).

So now the insulation was removed, mold and mice remediated, insulation HAS NOT been put back yet (further tightening house!), recommended air exchanger HAS NOT been installed, my equipment pulled and humidity is spiking.. where is the moisture intrusion coming from? am I missing something?

 

[Lee Stockwell]

Did I leave the sink running again?

 

[MamaBird]

Lee... I wish it was that easy! I've even traced every water line... not a leak to be found!

 

[Desk Jockey]

You're going to get some moisture through entrainment when outside conditions are that high. Especially when you have lower vapor pressure in the home. Every time the doors are opened, air containing much high ggp is coming in, just as around the windows but in much higher volume.

Not much you can do about that.

Have you done a calcium chloride test on the concrete slab?

My guess is that's your source of vapor diffusion. It sounds like they live in a marsh, that slab must be like a sieve with moisture passing through it.

 

[dgardner]

You're going to get some moisture through entrainment when outside conditions are that high. Especially when you have lower vapor pressure in the home. Every time the doors are opened, air containing much high ggp is coming in, just as around the windows but in much higher volume.

Not much you can do about that.

Have you done a calcium chloride test on the concrete slab?

My guess is that's your source of vapor diffusion. It sounds like they live in a marsh, that slab must be like a sieve with moisture passing through it.

Richard, Mama bird mentioned that the final outside conditions were 32 degree and 60% rh. Were you referring to the earlier conditions when you said "when outside conditions are that high"? My psyc chart says that's only 16 gpp, while the final inside conditions at 70% imply a much higher moisture level (she didn't mention inside temp, but at 72 that would be 82 gpp). If I understand this correctly (and help me if I dont) then air infiltration would not be the source of the moisture and it would have to be coming from somewhere else, like through the slab as you suggest. Is that more or less accurate?

 

[Desk Jockey]

Dan mind mind doesn't work like yours. I'm thinking of a gazillion things at once and only perused the post.

Its like this, I read a line...recall that hottie...read another line recall the other hottie...pay a bill...recall a hottie...respond to bawb...recall that hottie...respond to Nate recall the hottie.

Sorry I'm all fooked up!

Yes I do believe its the slab. I think even if you didn't want to do a calcium chloride test you could take some plastic and tape your hygrometer to the concrete and it would tell the story.

 

[dgardner]

Appreciate your response! I'm always looking to expand my knowledge. Perhaps some day I will be able to multitask as well as you...

 

[Desk Jockey]

LOL You mean when your mind begins to fail you?

 

[dgardner]

What were we talking about?

 

[Desk Jockey]

Not sure, I was thinking about a hottie.

 

[MamaBird]

LOL... that's why I'm probing your minds...
Dan you are right on 16 gpp and 83 gpp inside...
Moisture can't be coming from concrete anymore... I applied a water-chasing polyuria concrete sealer to the floor and walls of the basement. Spray foam is on the sill plate.. only point of intrusion I can't reach is where the 2x4's meet the foundation on the sill plate.
Any other thoughts?

 

[Desk Jockey]

Is there a sump pump?

Have you shot it with a thermal camera? Maybe the temperature differential would direct you to the source.

I also wouldn't trust the sealing product without proof. Place your hygrometer on the slab and cover it plastic and tape the edges. Monitor several hours later Then leave overnight.

 

[dgardner]

Improperly vented (or vent-free) natural gas appliances?