Am I Wrong? Long

Karl Laustrup

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487
Location
Wisconsin Dells, WI
I recently discovered mold on the lower frame rail of five windows in our home. I hadn't noticed this mold until I was washing windows one day late last month [April].

These are Pella Designer Series Casement windows that allow a mini blind to be in between the main dual paned glass and an inner third pane of glass. Neat idea and one of the reasons I picked them to be in our new home as well as the quality of Pella windows. You can read all about the building of our home by doing a search on Sawmill Creek" under "A New House".

I was purchasing blinds for installation in four of the eleven windows that did not already have them, so I emailed the sales rep with pictures to see if the person they were sending could look at these windows. The reply was to show the tech the windows and the pictures I had sent were shared with the sales reps manager as well as the service dept.
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During the two week period between the email and the arrival of the tech on May 10th, I was trying to figure out what could be causing this problem. I did have a humidifier installed on the HVAC system and was given instructions about setting the humidity level by the HVAC contractor. I was to observe the windows on a regular basis and if I noticed any condensation I was to lower the setting on the humidifier to dry up the air in the house. I checked at least once a week, if not more often, and the only windows that were showing any condensation were the bathroom windows after someone had taken a shower, so having this mold was puzzling in my mind.

During this two week period I have deduced that the mold on these windows, while not of the same intensity on each window, is more prevelent at the side where the crank handle and underlying hinge is located. Perhaps the windows are not sealing properly there and this is what is causing the mold. It is also strange that two of the windows are above heating vents, while the other three are not. One of the windows over a vent has the most mold while the other over a vent has a small to medium amount of mold. Two windows face south, one window faces north, one faces west and one faces east. One of the windows not over a vent has the second most amount of mold. There doesn't seem to be any other factor to tie the mold on the various windows together, except an air leak at the crank/hinge area.

May 10th arrives and the tech shows up at 7:30 AM with the blinds in hand and asks what else I have for him to look at. I show him the sliding door and then the mold on the living room window, which is one of the ones he will be installing the blind in. I explain that I have five windows with varying degrees of mold growing on them. One of his questions is if the mold is new? I explain that I just discovered it and I'm guessing it didn't grow overnight. One of his next questions was what the humidity is in the house. I explain that I have a humidifier and I think the unit is set at about 40-50%. I later found that it was set between 35 and 40% humidity and again I had no condensation during the winter months on any of the windows.

Disconnect the humidifier was his response. That was causing the mold because of high humidity during the winter months. The higher humidity is trying to get to the lower humidity outside which causes condensation and consequently the mold on my window frames. My response was disconnecting the humidifier was not going to happen for various reasons which I didn't go into.

My common sense understands what he is telling me, but the same common sense says that if that's the case then why don't all my windows have mold? I explain what I said above about the heating vents and that the windows are facing different directions and the only common bond I can see is the fact that the mold is heaviest near the crank/hinge. He has no answer except that it's all caused by humidity and don't use the humidifier any more. I lost my cool at this point as he wasn't going to even investigate if there could be a problem with the windows. I demanded a call from the sales rep or his boss to further discuss this matter. He went on with his work and I was pleasent for the remainder of the time he was here. He also left me a gas company report on heating and mold in new air tight homes. Very informative, but little I didn't already know.

A couple of hours after he left I got a call from his boss, the manager of the service dept. The conversation began cordially until the manager said turn off the humidifier and that was the cause of all my problems. Not, well maybe there is something else going on here that we should check. I personally don't know of any manufacturer of any product that doesn't have some defects from time to time. I guess, at least from this service managers perspective, Pella is perfect and their windows don't ever have any defects.

So here I am trying to decide if I'm totally out in left field and what my next move might be. I have thought about calling in one of those services that can find air leaks by putting a vacuum to the house.

I am going to write to Pella, but I thought I'd get some opinions from the vast knowledge bank here and at the "Creek" before I make a total "you know what" of myself.

Thanks for taking the time to read this rant and I look forward to any and all views on the subject.

Karl
 
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Hi Karl,

I think I would have followed the same course as you - dosen't make it right, just shared.:D

My opinion, and that's all it is, would be to first get out the bleach water and rubber gloves and get rid of the mold. You've got it well documented, so there's no need to allow it to continue to grow. The spores it gives off will only find another place to grow and you'll wind up with a worse problem, like mold in the air ducts.

You can check for drafts around the windows with a device like those the specialists use, or just a candle. Blow out the candle and, while it's still smoking, place it near the suspected leak. If there is air movement you'll see it. Of course, be careful with lit candles near curtains, etc. But, you already knew that.;)

Should you determine that there is air movement near the cranks, then you can get the service manager back on the phone and give him the facts. If that gets you nowhere, call Pella direct. I always give the local guy a fair shot before I go to the top.

Good luck!:wave:
 
Just some thoughts that came to mind as I read your post.
The house may be too well sealed to allow natural respiration. e.g. was the outside wrapped with visquine instead of tyvek?
Is there mold anywhere else? I would check everywhere, closets, corners, cabinets, everywhere.
From what you say, I'm dubious the windows can be blamed unless the installers had creeping crud on their hands and that 'mold' is the result. Unlikely.
BTW, 40% indoor humidity in the winter is not too high. About 45% is what I have read is considered healthy.
Keep us updated on what you learn.
 
From what you say, I'm dubious the windows can be blamed unless the installers had creeping crud on their hands and that 'mold' is the result. Unlikely.
Second that. One window with a problem could be a problem with the window. Five windows in the same house with a problem is more likely something to do with the house rather than the windows.

I'd be tempted to check inside the walls under/around the "problem" windows to see if there is mold there. (Maybe rent one of those fiber-optic camera probe widgets like the termite guys use?) You're not getting condensation on the windows, but you may be getting condensation on pipes or ducts inside the walls adjacent to them.
 
karl, my first thoughts where house wrap and hvac installation....are you "certain" that a quality wrap was installed correctly?.....if so then turn to your hvac system.......where are the returns in relation to the mold? are there sufficient air exchanges taking place in the rooms where the mold is growing? when a house is sealed a propperly designed hvac system becomes very important for both the buildings health as well as the occupents health.
just because you found mold on the windows doesn`t mean it stops there:eek: .....this could be a major problem? with all the "new" technology and materials on the market now it really takes more than joe and his crew of laborors to build a functional house......the fellow who designs the shell must coordinate with every single trade to make certain that the planned materials are installed properly and that all of a houses mechanical systems jive with eachother within the shell.......i really hope this is something simple! good luck and keep us posted...tod
 
Karl,
The humidity might help the mold growth, but mold needs something to use as food - typically dirt of some sort. Some of the windows almost look like the mold is growing on finger and palm prints. Maybe dirty hands during installation contributed? (thinking the bottom edge receives the most moisture versus top and sides) Has the mold stained the window?

Just another thought,
Wes
 
Looks like a normal NZ windowsill :eek:

But then we are inflicted with 90% humidity and temps around freezing outside, so DE-humidifiers are common to control that sort of thing.

I understand that the double glazing should cut down on heat loss and hence condensation on the glass, but what about the aluminium frames? They may very well be the coldest item in the room and hence the first place that condensation would form. The double glazing is probably better insulated than the actual frames.

If the windows were leaking outside air wouldn't that be drier than the inside, especially as it warmed up as it leaked in?

I think that reducing the humidity is probably the only real fix :dunno:

Cheers

Ian
 
Thanks for the suggestions so far.

I'd like to address some of the questions raised to date.

Wes, I thought the same thing with some of the mold. It was in the shape of finger prints. This is very possible and I would guess the prints were of the painter. I washed all the mold off using bleach and water right after the service tech left last week. No stains.

Tod, if you recall, from my "A New House" threads at SMC, I was here for everything that happened during the build of this house. Tyvek was used as a wrap material and was installed properly. Each room in the house has at least one supply and one return for the HVAC. In the master bedroom we have two supplies and two returns because of the size of the room. The returns in the two bedrooms [grand daughters and my mothers] are not more than 10' from the windows in question. The living room and kitchen windows are further away from a return, but the area is all open.

Lee, all the pipes run in the basement except where they come up to serve the bathrooms, kitchen etc. and are well away from the windows in question. I understand your statement about 1 window maybe, but 5 windows seems a little less plausible. However, what if a batch of windows came off the line and the weather stripping wasn't quite right around the area of the hinge?

Frank, while I haven't checked the whole house, I've checked the areas under and around the windows which had the mold. All appears OK.

I talked with the HVAC contractor today about the problem. While he didn't have any answers, he agreed that it is a strange problem. He also suggested that he's seen many strange things in the time he's worked in HVAC.

They do the thing where they put a big vacuum in your front door and then check for air leaks through the house. He said it could run about $200 to do the check, but if there are air leaks they'll find them. I'm thinking I might have that done, one to prove or disprove my theory of the windows allowing air seepage around the hinges, and two to see just how tight this house is.

What really frosts my cookies in this whole thing is the fact that VerHalen, the Pella rep for this area, didn't even offer to at least check the weather stripping or anything. It's just assumed that the homeowner is a dummy and it's all his fault.

Karl
 
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