Replacing roof

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Old 07-31-07, 11:10 PM
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Replacing roof

I am getting my roof replaced, shingles and sheathing. My questions are:
Can I have the ice and water shield installed onto the entire roof? If not, should I have 30lb felt instead of 15lb installed? To provide more info, I am having the contractor install more soffit vents and a ridge vent. I currently have a gable vent with a fan. Also, I live in PA.
 
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Old 08-01-07, 05:25 AM
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The ice and water shield should be 4' wide and run the perimeter of the roof. If you are having damage from water backing up under the ice during the winter, it is more a concern of proper insulation. Soffit and ridge vents will help. Ice damage is caused by excess heat in the attic space warming the ice from below which drips down the roof. The water drips below the snow on against the roof itself. When it gets to the bottom of the roof it freezes. As more water tries to get out, the exit point is blocked by ice, so it seeks the next available outlet, which is usually through the shingles.

What type and how thick is the current insulation in your attic? Adding some more will probably take care of you problems and a normal roof install will be all that is needed.
 
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Old 08-01-07, 06:55 PM
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You will likely want to have the gable vent and fan removed once your roof is complete. Of course, some schools of thought feel that more ventilation is never bad. Thats a whole 'nother can of worms. I wholeheartedly agree that checking and adding attic insulation as needed should be at the top of your priority list, as it will usually decrease problems with ice dams. It's also the best use of your energy dollars.

You did not mention the slope of your roof, or the type of shingles being applied- which may or may not affect the answer to your question.

Generally, however, one or two layers of ice and water shield near the gutter of the home, a layer along the edge of any gable ends, and a layer down the center of the valleys would be sufficient.

You definately do NOT want to use #30 felt if you are using asphalt / fiberglass shingles. #30 felt does not lay flat and will telegraph these imperfections through the shingles. If the roofing material is of another type, #30 may be appropriate.

Rather than using #30 felt, two layers of #15 would provide the same protection and would lay flatter. IMO, 1 layer of #15 is always good enough, but its fairly dry out where I'm at.

Graceathome has some info on their website about roofs and ice that you might find informative.
 
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Old 08-05-07, 10:34 PM
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The insulation in my attic is almost nill. By the looks of it, I would would say that there has not been any added since its construction in 1965. I've only owned it for three years. I plan on installing baffles then blowing in insulation. Concerning the roof felt, what if I used a product like Deck Armor from GAF instead of th 15lb felt? Regarding the slope, 80% of the roof has a moderate slope and the rest has a very steep slope. Also, thank you to everyone for replying to my post, I really appreciate it.
 
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Old 08-06-07, 08:03 PM
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Deck-Armor would be an excellent choice, and since you mentioned that your home has a moderate to steep slope, the ice and water shield is really only needed around the perimeter. There are a few areas of the country where they recommend 2 courses at the bottom of the roof, but those are mainly areas that receive LOTS of snow.
 
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