catherdral ceiling moisture with new roof

We have a 23 year old home with a high catherdral ceiling in the living room. I would estimate it to be about 28 feet high at its peak. We had a new roof (composition shingles) installed about 5 years ago and since that time we have had a problem with moisture in part of the ceiling. Dark/black streaks will form from the wooden center beam and run down both sides of the sheetrock. Our roofer has returned several times to repair the damage and revent the roof in that area. It only effects about 1/3 of the ceiling and happens every year or so. We talked to him again yesterday and he said there was nothing more he could do. It looks terrible and we are afraid it is going to cause permanent damage. The area is way too high for us to get up there ourselves and we were wondering if anyone knew how this could be repaired. Is there a particular venting system that will stop this? We live in the Houston area so hot summers are a given. Any help would be appreciated!

Thank you,
Peggy

 

You say the problems began when the roof was redone. Besides new shingles, what else changed? Did he add additional ventilation, or change the existing ventilation somehow? What type of ventilation does the roof currently have- ridge and soffit vents, can style "Lomanco" roof vents, power vents, etc?

Does the roof leak at all, or it just has black spots? Is it mold? Have you repaired/repainted it previously and it has reappeared?

Perhaps more information could help. I have no idea what the solution might be based on the information you've provided.

 

Based on what he's told me previously, he added several ridge vents. I don't know what kind but I will ask him next week. Our roof peaks in the center, if that helps. The roof doesn't leak (as in water hitting the floor) and the stains are brown/black streaks as if you can see the run of the water. It could very well be mold but it is too high for me to check out. He has repaired/repainted it 3 times in the last 5 years and needs to do it again.

If you could recommend the best type of venting for this situation, I would really appreciate it. I could then discuss it with him. He has an excellent reputation so I know he will come out again to do what is necessary.

Thank you,
Peggy

 

I would suspect that "possibly" you could have a problem with wind-blown rain entering the ridge vents. I'm assuming that Houston gets thunderstorms with strong wind, and the occasional tropical depression. Some brands of ridge vent are worse than others at letting in rain, but I can't suggest exactly which to stay away from, or which to choose. Other possibilities might be that the shingles might not extend far enough under the ridge... or the tarpaper underlayment (which should provide protection against "certain types" of leaks) beneath the shingles is insufficient... or the gap at the ridge was cut wider than recommended by the manufacturer of the ridge vent.

If it never leaked before and he has added ridge vent in that exact location, I'd say that's a safe assumption to make? I believe that the can style Lomanco vents are a better choice for areas prone to wind driven rain.

 

Thank you! I will discuss this with him on Monday. Hopefully, your suggestions will prove correct and he will be able to address them. I'll let you know the outcome.

Peggy