[bmancanfly]

I'm not sure which forum to put this in but here goes.

I'm having trouble with my fascia and soffit getting moldy and rotting. There doesn't seems to be any apparent roof leak to acount for the amount of mold/rot.

I suspect, but I'm not sure, that the roof venting design my be the cause. I live in a heating dominated climate (FL) and there are no soffit vents or ridge vent. Only gable end vent.

I thought this might cause a problem with the roof deck, but why are the soffits/fascia rotting?

 

[Willie T]

Without exception, mold and rot indicate a moisture retention problem. I'd first check all along the edge of the roofline. You have gutters? Always a potential trouble area. Gotta keep them, and the downspouts, well clear of debris.

One very common way that water enters the fascia is due to improper sub-fascia/fascia framing, and consequent bad installation of the drip edge metal. The sub-fascia or fascia is often too high, causing the drip edge metal to be installed with a "tilt back" that actually funnels water up under your shingles, and then down onto the fascia. It can't dry out down in there, so it begins to rot. Then that same rot spreads to the soffit.

 

[bmancanfly]

thanks for your reply.

there are no gutters, so that's not the issue. and the drip edge seems to be properly installed (that was my first guess too).

I'm thinking that the humid air in the attic may be condensing on the interior side of the roof deck (like after a cooling rain shower???) and dripping down to the soffit/fascia. But I'm just guessing.

I'm not even sure if the makes sense scientifically. Would the humid air condense on the underside of the roof deck?

 

[lala]

same problem

Willie T

The problem you described (fascia installed too high angling water back in under fascia) seems like the exact problem I have. A little of the fascia is rotting. Otherwise, all the way around the house there is mildew streaking down from the edges of the shingles onto the fascia and nails are popping out.

Obviously the rotted fascia needs replacing. What is your suggestion for resolving the problem for the parts that are not yet rotten? If all of the fascia is replaced, is there still a need to generally treat for any residual mildew?

(This house is eight years old; we bought it 1 1-2 years ago. The house inspector didn't catch this although the grey streaks were there. I just thought we needed to install gutters to correct the problem -- thank goodness we have not yet done that.)