logo Pinpoint Design & Build - Bob Freck - Carpenter

When Gutters and Shingles Cause Rot

2020-08-15 14:25:41

If I've heard it once, I've heard it a thousand times. "I thought the gutters were supposed to keep that from happening," says the frustrated home owner. Sometimes, when new gutters are installed, a year or two later, there's rotted fascia and soffit, and sometimes roof decking. One would think the obvious; that the gutters should have prevented this. In many cases, though, it's caused by the gutters and shingles together.

When gutters are installed, there likely isn't any thought about the shingles, but the amount of shingle that over hangs is important. You see, when shingles get laid, the first course of shingles must go out beyond the fascia, trim, or drip edge. By how much varies from one roofer to the next. Standard is about an inch. In many cases, it's much less. This over hang is so that water goes beyond whatever you have at your eave. If the over hang is less than an inch, and you have a four in twelve pitched roof, which is a very common pitch, then water can wick back up the bottom of the shingle. Then when the water hits whatever you have at your eaves, it follows on down. That's all well and good, and it's supposed to happen that way.

Now, when gutters enter the picture, the path the water takes must change. You don't want the water to go the same route, because sometimes, it'll get between the gutter and fascia, and eventually cause rot. The answer is in the shingle over hang. That one inch or less overhang really needs to be an inch and a half. This amount of over hang will cause the water to not wick up, but dump into the gutter instead. If your house is getting a new roof, and you have gutters, you could tell your roofer to over hang the shingles at the eaves by an inch and a half, and possibly save yourself some frustration down the line. If that's not the case, though, we have to still extend the roofing, and there are a few ways to do that.

One way of extending the roofing is with flat, metal flashing. Six inch wide flashing is best. That'll give you four inches to slide between the shingles and the roofing felt, and two inches to extend the roofing into the gutter. I also will bend the metal fifteen or twenty degrees, or whatever angle is appropriate for the roof pitch. Another way is with a gutter helmet that has four or so inches of flashing integrated into the profile. Those can also be color matched with the gutters. A third way is to actually add shingles under that first course, with the needed over hang. That last one is tedious and very time consuming, and I had to do it a couple of times, because the first two weren't an option.

So if you think you have some rot, give us a call, at (501) 517-4096, and I'll come on out and have a look. Now when it comes to rot, we're not going to just replace what's bad. We're going to find the cause of the problem and fix that as well, and you'll never have to worry about it again. Oh, and there's no charge for the consultation.