Ice, mold and a lazy contractor cause some major problems

Q. I have a two-story home in the Pittsburgh area that was built in 1998. In 2012, we had a new roof installed after a severe hailstorm. In December 2012, when I went into the attic to get my Christmas decorations, I noticed the entire roof on one side was damp, black and covered with mold.

I had the contractor who built the home and replaced the roof take a look at it. He acknowledged there was a humidity problem and said he believed there was too much insulation in the eaves and it should be lifted up with baffles and some removed as well. I also complained (which I had done before) that the bathroom exhaust fans should have never been vented into the attic. He told me they would correct it, vent them outside and spray the mold.

He wanted to install two power vent fans in the roof, but the entire roof has a ridge vent and a vented opening on each side of the house. I did some research myself and told him I felt there should be soffit vents for the ridge vent to work properly and that power fans usually do not work with ridge vents, so I was totally against them.

I suggested raising the insulation from the eaves and removing some, and adding soffit vents for the ridge vent to properly work. The response was: "I think that may fix it." He also said he didn't believe the bathroom fans were the problem, but I maintain they are.

I have not yet been able to get them back to correct the issues, even though I was assured it would be corrected prior to this winter.

We had a freeze/thaw last week and obviously my attic was extremely damp and wet and smelled from moisture. The last two days we were 7 to 8 degrees below zero. I had a major ice buildup on the roofing nails, underside of the roof and attic walls. It is now thawing and water is dripping into a bedroom, into the attic and through the siding outside on the second floor of the home.

This has been going on since December 2012. In September 2013, the contractor told me it would be fixed before it got cold, but I am still waiting. I am to the point where I want someone else to fix the problem.

I have contacted my insurance company today and am waiting for the claims adjuster to call me, and I may sue the contractor as well.

Any suggestions on how to correct this before I am replacing the entire top of my house? Any suggestions on finding someone in my area who is an expert on attic humidity and really knows how to fix it? Any and all help is greatly appreciated.

A. There should not be any insulation in cold eaves; it can get soaking wet if ice dams form and water leaks inside the soffits, and if there are soffit vents, the insulation blocks them. The insulation should be removed and there should be full-width baffles in each rafter bay to keep an open-air space between the soffit vents and the ridge vent. There should be full-length soffit vents and no gable vents or power vents. Air circulation between soffit and ridge vents occurs naturally by thermodynamics.

Bathroom, dryer and kitchen vents should never be discharged in attics; they need to exhaust to the outside through a wall or gable. They should not be vented through a roof in colder climates, through ridge or gable vents, or through soffits.

The combination of soffit and ridge vents can only handle attic moisture that emanates from the outside environment and any minor moisture that may be working its way through finishes. It cannot handle moisture dumped into the attic from the living spaces by fans and any other openings, however small.

The bathroom fans venting into the attic are responsible for the excess moisture and the mold on the one side of the roof; this is likely the side into which the fans discharge, or the colder north side.

Good luck with your insurance company, although I am not sure they cover a serious construction mistake - i.e. the discharge of the bathroom fans into the attic. You may eventually have to sue the contractor, but it is possible that a letter sent to him by a lawyer may convince him to shape up. Another option may be to contact the consumer protection division of your state's attorney general's office. It will contact the contractor asking him for a reply; this may help get him off his duff.

But you are right; at this point, you are better off having a reputable contractor come to fix the problems. The solutions are described above. You should not need to go to the expense of hiring an expert on attic humidity.

You should also check the type of ridge vent the contractor installed. If it is not an externally baffled ridge vent, consider having it replaced with one like Shinglevent II. An external baffle is needed to divert wind over the ridge and prevent it from driving rain and snow into the attic.

The mold can be left to dry and die, but if you are queasy about it, it can be washed or sprayed with a strong bleach solution.

Q. I have a question about "shadows on my ceiling." Sounds like a good movie title, doesn't it? About 10 years ago, my husband and I remodeled a stick-built, three-bedroom home that was built in 1969. We had the help of a contractor and have been very satisfied with his job.

I should mention that we replaced all of the Sheetrock and installed new insulation in the walls and attic. Recently, two areas in the ceiling have developed shadows - light gray areas between the joists that measure about a foot out from the center beam. I asked a few folks what it could be, and no one had any idea until a visitor said, "Oh, those are cold spots where your insulation has fallen away." I called a contractor and was told that I needed to re-insulate the entire structure with blown-in insulation - the cost is roughly $1,000.

I guess I'm asking for a second opinion; it seems as though insulation should last more than 10 years, shouldn't it? And is this "cold spot" theory true?

A. The cold spot theory is right on. It sounds as if the insulation has gotten wet or been moved or lifted in the areas where the gray shadows have cropped up. You mention two areas, but you haven't told me where they are in relation to the end walls of the house.

Here are several possibilities:

• Since the two stained areas are near the center beam, if you have a non-externally baffled ridge vent, snow or rain may have been blown in through the ridge vent and wet the insulation. I have seen this in several houses over the years, and in one in particular, it was so bad that the drywall ceiling was beginning to fall off. A carpenter removed several buckets of snow that had been blown in through a Cor-A-Vent ridge vent from the center area of the ceiling. Interestingly enough, it was also in Grand Isle, where winds are very strong.

• If the gray areas are near gable walls and you have gable vents, either snow or rain may have been blown in through them and wet the insulation, or less likely, turbulent wind currents may have blown away blown-in insulation or lifted up fiberglass. I have also seen this in a few houses over the years.

There may not be a need to have new cellulose blown in throughout the entire attic. And unless the cause of the problem is removed, it is likely to happen again. Consider having an experienced contractor check the attic to see what is really happening.

If the problem is caused by the ridge vent, it should be replaced with an externally baffled one like Shinglevent II. If the insulation was displaced by wind currents or became wet from snow or rain ingestion through gable walls, a metal baffling system can be installed or attached to the base of the gable vents flaring up at a 45 degree angle in an attempt to catch or redirect any ingestion. If you are dealing with snow and water infiltration, a large pan (at least 4 feet square, made of two-by-four lumber and lined with 6-mil plastic) should be set on top of the floor joists against the gable wall to catch the water and give it time to evaporate.

Q. Thanks for your reply to my question about basement wall insulation, but I do have one follow-up question. I saw you didn't include a vapor barrier between the fiberglass insulation and the finished wall. It seems from what I've read that some people include this vapor barrier and some don't. What is your opinion on this?

A. I didn't mention a plastic vapor retarder because I recommended installing rigid XPS insulation directly against the masonry walls. This will keep the framed walls with fiberglass between the studs at a warm temperature. This would cause the dew point to be inside the XPS, if at all, which does not absorb moisture. When the rooms are not used, moisture migration is reversed and works itself back into the rooms.

Keep in mind that if you use drywall and paint it, that in itself will reduce any moisture migration through the wall assembly. Plywood paneling would accomplish the same thing, but board wall finish would not. However, the dynamics mentioned would come into play just the same.

Interesting follow-up: This from a reader about concrete found in a tiled bathroom wall during a renovation. "The concrete in the wall sounds like the substrate from a 'mud job.' In years past, before the advent of concrete board, tile setters would mix a concrete bed similar to, but thicker than, a plaster wall with a concrete sand mix. They would level it out and apply the tile with a pure concrete mortar while the mix was still damp. This bed could be inches thick. The tile would be permanently anchored to the wall so tightly that you would see cracks going through the tiles instead of around it.

"Labor costs led to the demise of this technique, but it still is the gold standard for tile (installations), if only seldom used."

• Henri de Marne was a remodeling contractor in Washington, D.C., for many years, and is now a consultant. Write to him in care of the Daily Herald, P.O. Box 280, Arlington Heights, IL 60006, or via email at henridemarne@gmavt.net.

© 2014, United Feature Syndicate Inc.