Poor Roof Ventilation Can Cause Shingle Damage
LESLIE: Talking to Joyce in Montana where the roof is getting kind of off of things. What’s going on over there? Your shingles are falling off?
JOYCE: Yes, they’re falling off and they’re curling up.
JOYCE: And the roof is only about 12 years old.
JOYCE: So I …
TOM: Is it a second layer, Joyce?
JOYCE: No. This is – the house was built new and this roof is the original roof.
TOM: Oh, OK. Well that’s very unusual but if they’re falling off they’re telling you something and obviously you’re going to need to replace the roof.
LESLIE: Yeah, that’s a sure sign that it needs replacing.
TOM: And I suspect, Joyce, that your roof is not ventilated properly and it’s overheating because 15 years is not very long for an asphalt shingle roof to last. If the roof is – if the attic space is overheating, it’s not vented properly, that can cause this exact condition because the shingles dry out a lot quicker than they normally would if it had correct ventilation.
JOYCE: OK. OK, that makes sense because it does – there is a bedroom above the garage and it gets so hot in that bedroom that my daughter can’t sleep in it in the summertime.
TOM: Yeah, let’s talk about proper roof ventilation because I think we’re talking, obviously, about a new roof here.
LESLIE: And this would be the perfect time to fix all these things.
TOM: The correct roof ventilation would be a combination of ridge vents which go down the peak of the roof and then soffit vents at the overhang. And even if it looks like you may have perforated soffit vents, you need to make sure that the soffits are not blocked by insulation. If you have these two vents together what happens is as the wind blows over your roof structure it sort of depressurizes in the area of the ridge at the peak of the roof and that will draw hot air out of that space and it’ll go in or pressurize at the area of the soffit. So you get this flow that goes in the soffit, under the roof sheathing and out at the ridge and that’s a cycle that repeats 24/7/365 so in the summertime it takes heat out; in the wintertime it takes moisture out. You’ve got to get this flow working properly; otherwise, when you put your next roof layer on, again, it’s not going to last that long.
Now, if you plan on staying in this roof for the long haul we would recommend that you remove the first layer because especially in a situation where you’re overheating, if you have two layers of roof the first layer acts as a heat sink and will sort of store additional heat and that will force the second layer to wear out that much quicker. It usually cuts about a third to a quarter of the roof life off the second layer. So strip the first layer, improve the ventilation, put a new layer of roof shingles on and then you should get a roof that lasts you 20 or 25 years.
JOYCE: Does it matter what type of shingle I use?
TOM: No, a standard asphalt shingle is going to be fine. You know, lighter colors perhaps reflect a little bit better. But it’s more important that you get your ventilation straightened out.
JOYCE: OK. OK. Thank you.
TOM: You’re welcome, Joyce. Thanks so much for calling us at 888-MONEY-PIT.