New siding over old siding, interior mold...?

[Joe Cavasin]

Hey all - it's been a while since I was on here posting. I keep reading and hoping in a few short years I'll be able to be out on my own doing this, but for now it's homeowner insurance claims...

On that bent, I want to pick your brains. I recently inspected a home which had peculiar mold growth in the northeast and southwest corners of the home - both areas were bedrooms. This is a war-era bungalow, and has wide overhangs - 2'+ all the way around. The original siding - painted wood clapboard - was covered over about 3 years ago with new vinyl double 4". The j-trim butted up to the existing wood trim on the window. The joints between the j-trim and wood were not caulked. This was typical around the entire home.

So here is my policyholders predicament - they have had two other contractors come out to inspect and both have said that flashing should have been installed above the window trims, behind the vinyl. In my time seeing homes and reconstruction work, I don't recall seeing special flashing like this, and wonder if it would really stop the mold growth I saw, especially since none of the original wood siding was disturbed other than to have nails punched in it to hold the vinyl Problem is the mold growth is at floor level, and up to the top of baseboards. Also, a little on the two window sills involved.

I have a bit of a hard time saying that mold would only occurr in those two opposite corners of the home due to flashings that were not installed all the way around the place. Nothing odd with drainage either as this place had a solid basement/foundation, and it sits up off the ground approx 3' to the first floor which had the damages.

Have you run into mold as a result of not flashed/caulked new vinyl over old wood siding? OR is there something else we need to consider?

Thanks all
Joe

[Bob Elliott]

Water intrusion is a big issue that does all kinds of damage issues including mold.
Lack of proper flashing is one of the biggest water intrusion issues.

Two different Contractors said the same thing , so my advice would be to go to various manufacturer sites and study window install ,which will include proper methods of flashing.

[Matt Fellman]

I'd check with the occupants about the living haibits. Is there generally heat on in the rooms? People living there producing moisture?

I've seen several houses of people who got their gas turned off and have lived off a woodstove in the living room.... leaving the bedrooms really cold. If you don't heat a space but have people living in it you can get mold.

The exterior stuff is more likely but my theory might be worth looking into a bit.

[Michael Thomas]

No one knows what's going on under the siding around the windows unless it's removed - for example how the windows were originally flashed (or not) or how the existing trim and flashing (if any) was modified by the siding installers. In my experience without opening walls at the interior, careful inspection with a moisture meter (and IR, if available) may establish that the widow areas are in fact leaking, but cannot exclude the possibility of windows leaks.

[Joe Cavasin]

On the question of how the windows were flashed - they are replacement/insert type vinyl windows placed into the existing openings where old wood windows were removed. To my view, they were not flashed at all in these openings, just caulked. The flashing the contractors have mentioned as missing was to be between the new vinyl and old wood, and above exterior window trim - diverting possible water out and away...

Also, the j-trim was loose enough that I could pull it out an inch or so and peer behind it to see nothing except the original wood siding and multiple coats of paint - no new flashings or disturbances to the original siding I could see...

Does this help any, or make it worse - now all we know is we HAVE to get the siding removed to see how water is getting in? The people living there have not had any issues with gas being shut off - I already verified.

[Ken Rowe]

Joe,

It sounds like the flashing the contractors are talking about would be the drip cap. This should sit on top of the original brickmold and bend back under the original siding. My guess is it's most likely there but covered with several layers of paint. With vinyl window inserts the original window frame flashing usually is not altered except for the addition of a pan flashing, if necessary, at the base of the insert.

If the mold is not directly under the windows or within a close proximity it won't be from a flashing leak.

Typically the interior wall board on these houses will be 1/2 inch blue board and 1/2 inch plaster. If moisture is coming from the exterior, typically the plaster will release from the blue board and show signs of spalling.

Surface stains in the lower corners, especially in the bedroom can come from medium to high humidity levels in the home in combination with a lack of sufficient air flow. In other words something may be blocking the air flow in those corners. Beds are great for this. If it's just surface mold, it will clean up with a mixture of bleach and water and leave no stains behind. If it's from water intrusion from the exterior there will be water stains, spalling or cracking observed.

Loosen the baseboard in the suspect area. If it's from intrusion, you'll see mold behind it on the wall board. If not, it's surface mold.

[Rob Omstead]

I dont see it possible to determine the problem without actually removing materials. Why not start with the moldy wallboard and re-access. I am wondering if the mold was there before the vinyl siding or did it begin after the installation?
I would agree about window flashing being installed, never a bad idea.
Did the people ever open the windows?
Is there ventilation in the bedrooms?
Any pics?

[C Comegna]

Maybe this will help. Check to see if an insulating board was used behind the siding. If this an EPS board; either blue, pink or green; chances are this could be causing the mold growth. With new windows and siding the home becomes tight and does not breath. These boards come in 1/4" or 3/8 inch or 1 inch and each of them has a very low perm rating as low as .75. Under 4 is a vapor barrier. In essence they lock moisture inside the home and this causes "sick home syndrome". The only solution to this would be to increase the attic vent system with a ridge vent or whole house fan to draw the moisture up and out of the home at this point or take off the siding and install an XPS insulating board behind the siding. These insulating boards have perm ratings of 5 and allow the house to breath and trapped water vapors can escape. The best of these is known as Shelter Wrap.
If you have pictures I would love to see this as I am in the siding business at Newpro Windows of New England.
I don't see the flashing as much of an issue really.

[John Kogel]

Mold in the corners of the rooms, none under the windows?
Moisture condenses on cold surfaces. Moisture, dust, poor ventilation all contribute to indoor mold growth. I'm with Matt, the humidity is coming from the people inside. The walls are probably poorly insulated, if at all. There may be heat, but is it circulating to the corners?

[Stuart Brooks]

A standard report statement concerning flashing and J-channel:
Many contractors, and apparently building inspectors, consider J-channel trim as a flashing component. They add a little caulk and consider the door or window sealed. But, J-channel is not flashing and caulking deteriorates, cracks, and separates over time. This method cannot replace the required flashing that is to be installed over exterior doors, windows, or any other object that passes through the siding and has a weather exposure.

Every wall pediment I see whether it is foam, plastic, or aluminum, is stuck onto the face of the wall without flashing. Especially over garage doors. No flashing, and not even well caulked. I wonder where they think the water goes that runs down the wall and behind the pediment. Can anyone spell r-o-t-t-e-d h-e-a-d-e-r ?

[Darrell Covington]

Flashing of windows and tirm could be the problem, but don't fail to investigate the crawl space or basement if the house has either. Moisture in the crawl can migrate into the walls viz the mud sill or knee wall structure of the house. If the crawl is damp and not well ventilated, it could contribute to the problem.

[Darrell Covington]

Flashing of windows and tirm could be the problem, but don't fail to investigate the crawl space or basement if the house has either. Moisture in the crawl can migrate into the walls via the mud sill or knee wall structure of the house. If the crawl is damp and not well ventilated, it could contribute to the problem.