Mold in basement


  #1  
Old 12-08-14, 08:41 AM
U
Member
Thread Starter
Join Date: Aug 2013
Posts: 68
Received 0 Votes on 0 Posts
Mold in basement

I have a finished basement with mold on only one exterior wall along the bottom foot or so (see photos below). The issue now is figuring out the underlying cause of it. Some background info, we have a bathroom in the basement with a plastic shower stall that has a crack in the bottom of the stall that runs towards the drain. The shower is up against the same exterior wall that has the mold so one theory is that water has gotten underneath the shower and has run into the wall and is travelling along the bottom.

Other theory is that someone told me that insulation shouldn't run all the way to the bottom of the floor, as if there is any moisture on the basement floor it'll wick up the insulation and wet the drywall. So leave about a 6 inch gap or so at the bottom to stop this. But I've never heard of that.

Other theory is that our roof did have a bit of a leak above that same wall. We had the roof re-done in the summer so there shouldn't be any more leaks. But if that was the case then wouldn't there be signs of water coming from higher up the drywall? As you can see in the photos, the mold is confined to the bottom foot or so with no signs of moisture higher up.

Other theory is the water is coming in from outside. I don't think the grading is sloping towards the house and there is a walkway right next to the house (sidewalk slabs) right along the wall where the mold and moisture is. Don't know if there is a crack without pulling out the rest of the drywall and insulation and looking behind. For now though it looks like the moisture is only on the one side of the vapour barrier that touches the drywall.

As you can see in the photos, there is a seam along the bottom that shows that the wall there has been cut, possibly due to previous water damage that they replaced, but never addressed the underlying cause of the moisture. The date on the back of the drywall I took out there shows 2008 if that means anything. But based on the pattern, it looks like its coming up from the ground. It travels along that wall and then stops in the corner of a bedroom on the otherwise of a wall (last picture). Hope somebody can help me figure out where the moisture is coming from! I would greatly appreciate any insights.

This photo shows the pattern of the mold up the drywall (looking down at the floor).
Name:  IMG_4041.jpg
Views: 432
Size:  29.3 KB
This photo shows it along the wall (the doorway to the left is the bathroom).
Name:  IMG_4042.jpg
Views: 604
Size:  30.8 KB
This photo shows some surface mold along the bottom (had bookshelves there) continuing its migration towards the adjacent room (bedroom). Note the seam a foot and a half up from the bottom.
Name:  IMG_4036.jpg
Views: 373
Size:  15.6 KB
This photo is the adjacent room (bedroom) where the mold stops in the corner.
Name:  IMG_4038.jpg
Views: 356
Size:  26.2 KB
 

Last edited by umjorge3; 12-08-14 at 09:31 AM.
  #2  
Old 12-09-14, 09:57 AM
S
Member
Join Date: Nov 2014
Location: USA
Posts: 317
Received 0 Votes on 0 Posts
Hopefully others with more experience will respond, but, I do have a couple of questions and suggestions.

How long have you been in the house? I'm wondering if there were hints of something going on long ago (like musty odor).
You say there is a walkway on that side of the house. Is there an overhang (eaves) above that walkway? Are your gutters leaking or overflowing?

I wouldn't put any insulation in there until you solve the moisture problem. I also think you would do well to get all the moldy material out of there as soon as possible. Now, I believe Mike Holmes would advise that, if there is more than 10 sq. feet of mold, you need to call in the pros. If you happen to be the one to remove the moldy material, wear a respirator (not just a dust mask), and bag all that moldy stuff. Keep it open for a while. Let it dry out as much as possible. With it open (i.e., drywall and insulation removed), you can keep an eye on it and possibly witness where the moisture is coming in from.

Good luck. Again, hope some others chime in on this.
 
  #3  
Old 12-09-14, 11:26 AM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 10,524
Received 37 Votes on 34 Posts
I see those holes drilled through the lower portion of the drywall. Was this your attempt to dry out those areas? The holes would be allowing warm humid air into those cavities.

The bad news is it all must go, drywall, insulation, and it looks like a plastic vapor barrier. If thode studs are against the concrete they need to be moved, which would make room for a layer of rigid insulation. If the bottom plate is not pressure treated, it needs to be.

More bad news. That looks like a vinyl floor, but regardless, it is most likely that the mold has gone underneath the flooring. Time to talk to your insurance company before you remove the mess, they need to see what you are seeing. Hopefully they don't exclude mold issues.

Your source of moisture could be more than one, but use of a vapor barrier along with fiberglass insulation has been identified as a moisture problem. See photo #2 in link below.

BSD-103: Understanding Basements — Building Science Information

I'll let you read and check back later.

Bud
 
  #4  
Old 12-09-14, 01:04 PM
U
Member
Thread Starter
Join Date: Aug 2013
Posts: 68
Received 0 Votes on 0 Posts
Thanks for the replies. We moved into the house in August last year. Basement had a bit of a musty smell but nothing out of the ordinary of a lot of basements in older homes around here. Did not notice any obvious signs of water or moisture back then. We have had in the last year heavy snowfalls with plenty of melt last spring and a flash flooding event this last August and neither times did any water show up in the basement. And yes there is eves on the side of the house but I should mention that the roof, along with the soffits and facia were all re-done in August this year. Before then the fascia was so rotted and there was no drip edge on the edge of the roof, so whenever it rained water would be dripping (almost pouring) between the troughs and the fascia and would pool and collect quite a bit on the walkway against the house. If that was the case though then wouldn't there be signs of moisture higher up the walls? As I said so far only the bottom foot of the inside of the drywall has mold and moisture. In order to be sure though, I'd have to remove the insulation and more drywall to see higher up. I threw away all the drywall that had the mold on it but haven't cleaned up the mold sticking to the vapour barrier, just in case I wanted to bring in a professional to look at it.

I drilled some coring holes to check for mold along the wall, since I was going to likely tear it out anyways. Again its only this one wall that has it. I'll have to check underneath the vinyl for any mold. Its a cheap glue on type. There was mold behind the vinyl base trim through as I peeled it back. After skimming that article they seem to think that a plastic vapour barrier inhibits inward drying and that rigid is the way to go. If its only that wall that's problematic then I can put in rigid. Right now though I really want to find the source of the moisture. Again thanks for the replies
 
  #5  
Old 12-09-14, 02:12 PM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 10,524
Received 37 Votes on 34 Posts
Most people relate moisture to water (its liquid form), but the more evasive form is moisture vapor and it travels through concrete with ease. If there is a vapor barrier on the inside, the moisture level behind the VB will increase until it matches the outside, the soil.

But then there is the moisture in the air inside the house. If any part of those walls is allowed to get too cold the moisture in the air will condense on the drywall and feed the growth of mold.

You comments that this area looks to have been repaired before is probably correct. Very common for home owners to clean things up and cover then with a fresh coat of paint.

One more link for new home owners, covers many topics.
http://www.buildingscience.com/docum...build-renovate

Bud
 
  #6  
Old 12-10-14, 02:47 AM
S
Member
Join Date: Dec 2013
Location: usa
Posts: 1,348
Received 1 Vote on 1 Post
whatever the cause, you need to remove the drywall & insulation 2' above the damage ( holmes doesn't have a budget so he can call in anyone he wants ),,, if it were us, we'd monitor to see the source of the wtr 1st then resolve it - have 1 to look at today just like yours,,, even w/o seeing it 1st, i'll bet its exterior wtr leaking inside
 
Attached Images  
  #7  
Old 12-10-14, 08:04 AM
U
Member
Thread Starter
Join Date: Aug 2013
Posts: 68
Received 0 Votes on 0 Posts
Thanks for that publication it looks like a useful reference guide.

Could the weeping tile be no good? Since the moisture is confined to the bottom and that's where the weeping tile would be. Its an old home so I'm not even sure if there is a weeper but there is a pipe that comes into the floor drain.

Any thoughts on the crack in the bottom of the shower stall? How do I determine the source of moisture without ripping out a bunch of stuff? I don't want to rip out the shower to discover that's not where the moisture is coming from, or dig down to the footing to discover that isn't the problem either. Its winter here in Canada so I can't do anything outside.

Mike Holmes says that the number one entry point of water is windows and doors. There is a window right above where the mold is but again as I've said, no signs of moisture higher up (but I haven't looked behind the insulation yet against the foundation wall).
 
  #8  
Old 12-10-14, 01:42 PM
airman.1994's Avatar
Member
Join Date: Dec 2005
Location: VA
Posts: 5,795
Received 8 Votes on 8 Posts
1st issue I see is you have a vapor barrier. That should never be used in a below grade area because it cant dry out.
 
  #9  
Old 12-11-14, 01:24 PM
U
Member
Thread Starter
Join Date: Aug 2013
Posts: 68
Received 0 Votes on 0 Posts
That's an interesting theory that I've never heard of. Could the vapour barrier itself be causing condensation on the wall because there is no thermal break? That seems like a logical source of the moisture, as its confined to the bottom, where the coolest air is and where the condensation is happening. Anybody else have thoughts on that? Be great if that's all it was and not a foundation problem.
 
  #10  
Old 12-11-14, 02:36 PM
B
Member
Join Date: Oct 2008
Location: New England
Posts: 10,524
Received 37 Votes on 34 Posts
One indication of where the moisture is coming from might be where the mold has formed, although once any moisture from inside or outside reaches the bottom of the VB it can end up on both sides. Is there mold inside the VB, it looks like it in the pictures?

Not all walls will be the same temperature. The shower you mention would keep that section of basement wall much colder.

Photo #2 in that BSD-103 link I gave you above illustrates the results of having a vapor barrier over the studs in a below grade basement. Note their picture also shows the majority of the mold at the bottom.

As for conflicting information, there are still code officials requiring installations like yours even though research like BSD has well documented that approach as being a problem. Dig around the BSD web site for more links and if you need additional I can source them.

Bud
 
  #11  
Old 12-12-14, 07:21 AM
U
Member
Thread Starter
Join Date: Aug 2013
Posts: 68
Received 0 Votes on 0 Posts
Thanks a lot for the resources it helps a lot. I feel it could be a condensation issue and that I'll need to replace the batted insulation and vapour barrier with a rigid or spray foam solution that's mold resistant. I'm just wondering if I should leave the wall gutted until spring to make sure it isn't coming from water outside, since I won't know that now that's its winter. Would that be obvious in anyway now in terms of seeing cracks? How do I even know if those cracks are leaking? How big do they have to be to cause concern? Then theres still the matter of the cracked shower stall bottom that I should replace anyways.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: