Bad Advice Could Be Cause Of Ceiling Leak — Chicago Tribune

Bad Advice Could Be Cause Of Ceiling Leak - Chicago Tribune

Bad Advice Could Be Cause Of Ceiling Leak

A—Several things could be causing these water marks. I noticed that, throughout your description of the insulation and air space that compose this ceiling, no mention was made about the existence of any vapor barriers. (The diagram you included with your letter doesn`t show one, either.) If this wasn`t just an omission on your part and you don`t have this barrier just below the 4-inch insulation, then this is most likely the cause of your problem in a nutshell. My associate on «This Old House,« master carpenter Norm Abram, tells me he`s heard that some contractors in the Midwest (where you`re writing from) aren`t recommending vapor barriers in situations like this.

If that`s what happened here, it`s the perfect place for this type of thinking to create serious problems. You see, the purpose of such a barrier is to prevent warm, moist air from escaping into insulated areas. If you don`t have this protection, there`s nothing to stop this air from penetrating through the insulation. When it reaches the cold roof areas, it`s bound to condense and drip back down. In addition to ruining your insulation, this water has the potential to create very serious moisture and rot problems down the road.

Even if you do have a vapor barrier, recessed light fixtures in a cathedral ceiling can cause virtually the same type of thing to happen. The weak spots or «holes« these fixtures make are ideal places for warm, moist air to escape. (In some installations like yours, I`ve actually seen water dripping out around lights like these!) That`s why we usually don`t recommend recessed lighting in cathedral ceilings.

Unfortunately, these problems aren`t that easy to fix. If you don`t have a vapor barrier, there`s not much you can do to correct the situation without taking the ceiling down. And the best thing to do about recessed lighting fixtures, if you`ve got them, is to have them removed.

If neither of these situations exists, there are two other things I can think of that might be causing the water stains.

It sounds like your ceiling is correctly vented: You`ve got vents along the eaves and the little attic space that`s left is also vented. But even though you`ve left adequate air space in the ceiling, if the air passage from the eaves is blocked, the ventilation system won`t work properly. Because you have no access through a cathedral ceiling, a problem here can be difficult to determine unless you did the insulation work yourself. Based on the detail of your diagram, I`ll bet you did do this job and should know whether air is free to move through the vents.

Finally, ice damming may also be the culprit. Was there a lot of snow and ice build-up on your roof edges this past winter? If so, water may have been forced under the shingles and through the roof.

Bad Advice Could Be Cause Of Ceiling Leak - Chicago Tribune

The best way to prevent this kind of damage is to have a waterproofing membrane applied under the shingles when a new roof is put down. If you think ice damming may be your problem but a new roof is years away, then snow belts or electric cables, although not as efficient or attractive, are other alternatives.

Q—How can I remove cat urine and oil from my garage and basement concrete floors? I`ve tried everything, including bleach, lemon juice and strong detergent, with no success. Do you have any solutions?

A—As far as I know, there`s no way to remove oil or urine stains completely from concrete. You say you`ve already tried bleach and strong detergent. Although this won`t remove the spots, as you`ve discovered, it should eliminate the urine odor.

If the spots are particularly bad, painting the floor will improve its appearance and protect it from such easy penetration in the future. Before you do this, make sure the slab is free from any petroleum-based products you may have used to try to clean it. Then use a primer and a paint specifically developed for this application. Be aware, though, that once painted these floors will become a maintenance project in the future, because chipping and peeling over the years is not uncommon.

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