Spray foam insulation did this?

[mfglickman]

We had spray foam installed in the rim joists and between the floor joists above the crawl spaces in our Cape house last Fall. The original house was built in 1758 but the problem appears to be in the 1970's addition.

I was picking up kid toy clutter and moved a box of toys by one of the fake antique beams in the room, and found this (see pic). It's gray and fuzzy.

The only thing that we've changed in the house since last year is the insulation. The first winter/summer we were here, we saw no mold. No idea about the hard line at the bottom - there was nothing against the beam, just a toy box (no mold) near the wall.

Thoughts? Help?

 

[begreen]

Not sure if it is related to the spray foam or not. Could it be coincidental? This looks like moisture accumulating at the base. Is the fake beam open on the bottom to the point where cool air from the crawlspace can get up in it? Or is it possible that moisture is leaking from above into it?

 

[Backwoods Savage]

No idea Mary. We've not had that problem.

 

[semipro]

Its a little hard from the photo and description to tell what's going on.
Is it possible that water is getting into that wall/beam from above?
My thought is that the insulation from below is acting as a dam and that water that might have been leaking through to the crawl space before is collecting inside the wall/beam.

 

[Ashful]

Any chance to post a photo that zoomed out far enough to see what's going on there? That photo reminds me of those old National Geographic (?) articles with close-up photos of familiar objects.

 

[begreen]

If this is a false beam I would uncover it (wearing a mask so as to not breath in mold spores) and remove the covering. You need to investigate where the moisture is coming from. Don't delay, black mold can lead to nasty long term allergies.

 

[woodgeek]

Is the rim in this are well above grade outside, or close to grade? Is the foundation outside 'wet'? Might be a capillary issue with the foundation?
What does the siding outside the rim look like? Can the rim joist 'dry to the outside' through the siding?

OR

if this is the area of the bottom plate, upstairs, it could be a little colder than before, because it is no longer being heated from below. If you have high indoor humidity in the winter, and this is the coldest spot in your house interior (shielded behind a toy filled box), then this is a condensation point.

If your winter humidity is too high, you will get condensation somewhere, windows, the random cold corner, baseboard or crown molding. Buy a hygrometer, clean up the mold, and try to keep the humidity under 30% this winter. And put the toybox on an interior wall.

 

[mfglickman]

Hmmm, interesting questions. This is actually a "real" solid wood beam; I refer to it as "fake" because it's intended to match the hand-hewn 18th century exposed beams in the rest of the house but it totally doesn't. It is, however, solid wood. The mold line starts a couple of inches above the floor (?) and is only on the three sides of the beam that are in the 1970's addition. The backside of the beam is in the dining room, part of the original house, and has no mold.

This weekend DH and I pulled everything away from the walls, moved furniture and lifted carpets. Found mold along the bottom of the leather sofa (which was new 2 years ago, has never been wet, has been on a newish wool rug for 2 years, and is at least 8 feet away from the beam. The rug underneath it looks fine, and it does not reach to the wall where the beam is, either.). Other than that, nothing, nada, no other signs of mold or damp.

I'm really kind of wigged out at having mold inside my house. Sent a note to the sofa manufacturer to see if we have any recourse there...but I can't help but wonder about the relation to the new insulation. Weird and unsettling.

 

[peakbagger]

My swag is that the new insulation acted as air sealing. Previously there was enough air circulation from external leaks that there was adequate air movement to keep things dry to prevent mold. Get rid of the air leaks and at the same interior relative humidity, mold may start forming as it is not diluted with incoming drier air?

I expect you need to sample interior humidity and see if its high, then chase down the cause.

 

[woodgeek]

Indeed. One big factor with any airsealing is humidity. In traditional construction, everything is always too dry in the winter, and you can add big humidifiers and often they can't keep up. After (extensive) airsealing, or in well airsealed new construction, the problem is often too much humidity, which ends up finding cool spots and condensing or supporting mold. If its on your windows, at least you see it. Generally modern construction materials are better mold food than older materials, and the 1970s were not famous for their awesome airsealing or insulation methods. Maybe you have an insulation gap or an airsealing bypass chilling that area?

So, any other evidence for too high humidity? Fogged windows or storms? Mustiness in some areas of the house? It seems unlikely that your house is super tight at this point, but it is likely tighter than before the foam. My hypothesis is weak. You would need some source of water vapor in the winter, like a wet/porous (old) foundation, no bath/shower fans, tropical fish collection, dryer vented indoors, giant whole house humidifer set to 40% RH. Got any of those?

 

[mfglickman]

Indeed. One big factor with any airsealing is humidity. In traditional construction, everything is always too dry in the winter, and you can add big humidifiers and often they can't keep up. After (extensive) airsealing, or in well airsealed new construction, the problem is often too much humidity, which ends up finding cool spots and condensing or supporting mold. If its on your windows, at least you see it. Generally modern construction materials are better mold food than older materials, and the 1970s were not famous for their awesome airsealing or insulation methods. Maybe you have an insulation gap or an airsealing bypass chilling that area?

So, any other evidence for too high humidity? Fogged windows or storms? Mustiness in some areas of the house? It seems unlikely that your house is super tight at this point, but it is likely tighter than before the foam. My hypothesis is weak. You would need some source of water vapor in the winter, like a wet/porous (old) foundation, no bath/shower fans, tropical fish collection, dryer vented indoors, giant whole house humidifer set to 40% RH. Got any of those?

Since the central heating and cooling are now much, much worse after sealing and insulating (crawlspaces are cool and warm as needed) I'd say we've effectively sealed that part of the house, but it's nowhere near as tight as new construction. The old house foundation is dry laid; I took pics once to show the construction as you just don't see it anymore. Also shows the old part of the house's real hand-done beams: http://s290.photobucket.com/user/superdog_photos/library/foundations and beams?sort=3&page=1 and this is the interior. There is one shot of a really big room with a china hutch on the wall, that's the 1970's addition: http://s290.photobucket.com/user/superdog_photos/library/1750s House?sort=3&page=1

So - dampness. No condensation on windows. When it rains water drips down the old chimney, even though we had it re-flashed, sealed and new caps put on it 2 years ago. This is new. The roof also leaks in some spots but that is NOT in the budget so we deal with it with buckets. When we do the new roof, we'll want to insulate with better stuff (right now attic is done with about 20" of spray in about 2 years old). Most of our heat from the wood and pellet stoves go out the roof at this point, as they are no longer sucked out the floors and walls (walls had blown in insulation done last year, but there are still drafty gaps in the old section). Last, when it's rainy for days on end, it does feel damp in here, esp things like the wooden stair railing feels tacky/damp even though there are no windows/access for it to get wet.

I always wanted a real antique house and I do love much about it but this stuff just makes me crazy!

 

[semipro]

I'm still trying to get a handle on what we're looking at.
You're calling this a "beam" which is a horizontal member.
Perhaps this is really a post which is vertical?

 

[mfglickman]

Yes, it's a post, sorry! The mold is near, but not touching, the floor.

 

[SmokeyTheBear]

If you have known issues with your roof, where that water comes out or possibly pools can be many feet from where it comes in. The entire area from where it comes in to where it exits or pools is subject to possible mold growth.

This would have zero to do with your insulation job per se , however the new insulation could be preventing moisture from exiting as it should provide a fairly good water tight barrier.

Some exploration in the wall cavity is called for.

 

[woodgeek]

Thanks for painting a picture. Hard to say too much. I suspect with a leaking roof, and perhaps some saturated insulation (?) and blown in walls, you have enough water sources, and low enough air leakage that you sometimes get a combination of high indoor humidity and outdoor cold. The place prob dries out in the winter, but during the first big cold spell, you get the combination of cold + humidity + food = mold.

I would say the water intrusions are a bigger concern than the mold, and fixing those will fix the mold. Water runs all over the place in wall cavities, at least it did in my house. Other than that I would rec getting a humidity meter, and running the AC to keep under 70% RH in the summer/fall and hope to get below 30% in the dead of winter. If the summer is the problem, your AC might want a tuneup/fix. You might get an outdoor humidity sensor too. I use mine to know when I should open windows (cooler AND dryer outside). A lot of free cross-ventilation from open windows on fall dry days might be helpful when the RH is too high?

 

[woodgeek]

If you have known issues with your roof, where that water comes out or possibly pools can be many feet from where it comes in. The entire area from where it comes in to where it exits or pools is subject to possible mold growth.

This would have zero to do with your insulation job per se , however the new insulation could be preventing moisture from exiting as it should provide a fairly good water tight barrier.

Some exploration in the wall cavity is called for.

Yeah. Previously the water leak might have drained to the crawl, and now it is stuck there (on the beam).

 

[semipro]

Yes, it's a post, sorry! The mold is near, but not touching, the floor.

What does that post sit on? Does it extend into the crawl space past the foam insulation?
Maybe that end of the post is cold and water is condensing there (someone else may have mentioned this).

That distinct line of growth versus no growth on a solid post is what is throwing me. Perhaps there is some sort of coating on the lower portion preventing mold growth?

If not a condensation issue then I suspect water is accumulating at that end of the post whether its coming from the top and a roof leak or wicking up from the bottom somehow.

 

[Seasoned Oak]

Bottom line,FIX THE ROOF. Even if you stop the water from entering that location,its probably coming down inside your walls. Fix the roof,and you wont have to deal with the resulting water everywhere.

 

[mfglickman]

OK, thanks all. I'd love to fix the roof but after $10K in insulation I don't have another $10K for the roof. It will need a total tear off, probably some re-configuration of the supporting structure, and insulation. Ugh.

 

[webbie]

My NJ house had all kinds of moisture problems. It was built 1960 or so, before they thought enough about these things.

It was built with electric heat, so they tried to seal it well by putting a barrier of plastic in the walls between the insulation and sheetrock. This ended up making it so the walls conducted moisture up from a (wet) basement, which then condensed inside the roof sheathing! I had to rip off the entire plywood from the roof and re-do.

Complete retrofits to avoid moisture are very difficult to do, so I try to control it in various ways. My attic had a good ventilation fan as well as the normal vents - and the fan was on both a humidstat and a thermostat. I always use a dehumidifier in my basements or crawl spaces. I purchased a commercial one for the crawl in RI, which is fairly wet. It keeps the % at about 55, which is good.

 

[Seasoned Oak]

OK, thanks all. I'd love to fix the roof but after $10K in insulation I don't have another $10K for the roof. It will need a total tear off, probably some re-configuration of the supporting structure, and insulation. Ugh.

You could always patch it . Most roofs can be spot patched. By the time you get around to a total re-do you may have a lot more damage.

 

[begreen]

If water is traveling along beams before you see it drip, there could be water in the walls. This has been a wet summer back east. I hate to suggest more spending but the roof is a real priority. See if you can get it at least patched to make it through the winter. Mold in the house walls is not good.

 

[Seasoned Oak]

OK, thanks all. I'd love to fix the roof but after $10K in insulation I don't have another $10K for the roof. It will need a total tear off, probably some re-configuration of the supporting structure, and insulation. Ugh.

I would have done the roof first. Leaky worn out roofs are a priority. I left one go i could have replaced for 2k ,by the time i had it redone it was 6k, and i did half the work myself .The extra was to fix all the water damage.

 

[mfglickman]

You could always patch it . Most roofs can be spot patched. By the time you get around to a total re-do you may have a lot more damage.

I don't know what to patch. We had a guy patch a leak that we found in back, and it leaks still when the rain / wind are just right. It's just "lucky" that this leak comes onto my kitchen table so I know about it without a doubt.

We also had the chimney flashing done, sealant put on the brick, new caps/seals on all the flues. Yet water dripped onto my pellet stove last week (the nerve!).

I did have a roofing guy come to look today. He said that there is only one layer of shingles so he could do another one over (and he wants to do metal - which I'd love but I fear what the cost may be). Metal would allow us to add a layer of 3 inch foam over the whole roof before adding the new roof on top...hmmm...

 

[Hearth Mistress]

For what It's worth, I've had the same problem here all summer. Live an 1860's restored bank barn. Living room is the original foundation all stone, windows are at ground level so we are literally "sunk" into the cliff side. Floor is original random wood plank but dirt underneath. With all of the rain, dampness and humidity this summer, we had mildew growing on the stone walls, floor beams, under the area rug and on the bottom of sofa as well, just a few inches up the walls, similar to your photo. It has been so damp, we even have night crawlers working their way up through the nooks and crannies into the living room (stepping on them in bare feet is gross)

We steam cleaned and bleached the walls/beams down and plugged in a dehumidifier which kept filling up fast. It's been chilly at night but in the 70’s during the day so we haven't lit the stove yet this season but I know that nice dry heat will do a better job than the dehumidifier.

Good Luck!