I have a 1975, 1550 sq ft house with a low slope roof located in Saskatchewan Canada. I have an single vehicle attached garage on the north side of the house; therefore, the roof is fairly long.
The issue I have is, ever since I moved into the house 6 years ago, every spring when it warms up I get a leak down along the main support beam in the house. (the beam is located about 4 feet from the north wall which is common to to the house and garage). If I look up in the attic I can see some frost build up along the north sides roof and a bit on the insulation. Because of the low slope it is impossible to get close to investigate further.
The problem seems to have gotten worse this year and may have something to do with me adding another R20 of blowin insullation last year. When I look up in the attic I can see a fair amount of light along the south side (soffit) but because of the attached garage there isn’t much light on the north side. I should also mention that I have 2 - 12 inch wind turbines on the roof. I dont believe I have anything venting into the attic (dehumidifiers, bath fans etc…).
The roof is shingled with asphalt shingles (look in good shape).
Any ideas on what causes this problem. I suspect it is a lack of intake ventilation (no soffit on the north side). How do I eliminate this problem? What products are available to be installed on this type of roof etc…