Unwelcome Thaw

Two or three years ago obvious wet spots started showing up on my ceiling.  An quick investigation revealed it was the result of melting snow in my attic.  What to do?  Well, one time that it happened I put a fan up in my garage to help dry it out.  The problem is that my previous homeowner blew three to four feet of insulation into the attic, making most of it inaccessible, except for the area above the garage.  Luckily the wet areas were in the kitchen close to the garage, so I was able to clear out most of the snow and dry it out with the fan.  Unfortunately that was not the only spot that was a problem.  Another time it happened in a bathroom, where the ceiling and wall were affected.  I was able to access the area above the bathroom because there is an entrance panel in a closet nearby.  That time I removed enough snow to fill a bucket.

The reason I did not contact a roof specialist for help is that I thought maybe these incidents were just flukes, since this problem had not cropped up to this extent in the first five years of living in the house.  Last year the winter was mostly mild with very little snow until March, so it was not a concern then.  But this winter, with the first big windy snowfall, quite a bit of snow must have blown in, as four days later when the temperature warmed wet spots showed up on the living room ceiling.  This is an entirely new spot for the problem.  I have also come to the conclusion that this has only became a problem recently because my next door neighbor added on to his house in the back.  His house is a two story, whereas mine is a ranch, and so logically snow could blow off of his house onto my roof.  The part that he added onto his house must have changed the wind pattern enough to make it much more likely that snow can blow into the vents on my roof.

At first I was skeptical that this could happen.  Why would it be acceptable to install vents that would allow snow to blow in?  I know that builders are prone to using cheap materials when not under the direction of a future homeowner, but shouldn't there be standards for this?  I guess not.  I live in one of the windiest parts of the country.  Combine that with a fair amount of snow each winter, and this should be foreseeable.  It could be that the vents are not the wrong vents, but that they were installed incorrectly.  Either way, I guess I am going to have to do something about it.  Over the long term this could lead to rotting wood, in addition to messed up insulation and the stained ceilings.