I have a garage roof which has a ridge vent installed (previous owners had house re-roofed about 5 years ago), and there are no soffit vents and no gable vents in the garage. The inside of the garage is unfinished and I am able to see the plank sheathing.
Whenever it rains, I notice significant amounts of leaking from the upper section of the back side of the garage roof, enough to puddle on the floor. I notice that the water drips down the very first set of nails and it also seems to be running down the plank sheathing until it hits a joint, and then dripping down the roof rafters.
The water entry is only from the roof on the back side of the garage, and seems to originate at the first row of nails used to nail the cap shingles on.I don’t see any water penetration before this first set of nails. See attached an image below.
After getting up on the roof to inspect, the only thing suspicous was that on the front of the garage, the cap shingles over hang about 1/2″ infront of the ridge vent and on the back of the roof, the cap shingle does not overhang the ridge vent at all, and ends flush with the honeycomb.
I also noticed that the each section of the honeycomb vent material is not butted up tightly to each other, some sections have 1/4″ gaps between each section.
Does anyone have any ideas? I am currently suspecting improper ridge vent installation, and the lack of overhang on the cap shingle.
Replies
the cap shingle does not overhang the ridge vent at all, and ends flush with the honeycomb.
I also noticed that the each section of the honeycomb vent material is not butted up tightly to each other, some sections have 1/4" gaps between each section.
There's your huckleberry. Most ridge vents have some sort of mechanism to stop water from blowing in. But if there's a gap between the sections, you've probably got a clear channel for water to enter.
The honeycomb ridge vents are not very good, and the poor installation makes it worse. Probably the best thing to do is to tear it off and replace with better quality, properly installed.
Make sure, when the old ridge is off, that the shingles go all the way up to the slot and don't stop too short. The top-most course of shingles should have required trimming to not block the vent hole.