Grading

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Old 11-05-10, 04:56 PM
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Grading

There's a lip at the end of my roof decking that sticks up an extra 1 1/8" to 1 1/4" higher than the rest of the decking. Is this normal? Or would this require extra plywood "build up" to stop puddling? There is very little grade to the roof. The house is 54 years old and has had a new roof built over the old one twice. So there's 3 layers now. I will have it all removed.

 
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Old 11-05-10, 06:41 PM
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I dont know if its normal or not but I've seen it somewhere else too, but on a concrete slab. Its probably good if the water doesnt form puddles on the roof.
You can probably also remove some of the excessive material instead of building up the whole roof (unless its a load bearing component where that might weaken it), but if you build up the whole roof you might be able to make a greater slope for the water to drain.
Since its wood does it change volume in different climate conditions?
 
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Old 11-05-10, 07:18 PM
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Either it serves a purpose or it doesn't. This is a rock roof. Maybe it keeps the rocks on the roof. Maybe a roofer can answer this. Shaving off the excess ought to work. Circular saw?
 
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Old 11-06-10, 06:24 AM
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It looks as if it were a deck at one time and was covered with asphalt shingles/roofing later. The rim should have been shaved down to match the decking so you wouldn't have the puddling effect. A circle saw, reciprocating saw or other type would do the job. Be sure to install a drip edge so the water will not run back under the shingles via capillary action.
Second glance....is this a flat roof???
 
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Old 11-06-10, 01:04 PM
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The roof has a slight pitch. It has always had tared roofs. I think at one time they may have added this rim because they kept building up the height of this roof.
 
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Old 11-07-10, 01:51 PM
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Makes sense. I would trim down the lip and start over with a properly flashed BUR if that is what you are going back with. That lip will prevent the water from flowing properly off the newly installed roofing.
 
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Old 11-07-10, 02:51 PM
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They're going to add a 4-ply roof system. Even with that, should there be a flat transition to the lip or should the lip be raised a bit?
 
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Old 11-11-10, 06:11 AM
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Its suposed to be there. There was insolation of that thickness on the roof first and that board all the way around gives a solid surface to nail the drip edge to. Replace the insulation board (thats what all that dirt looking stuff is, it has deteriorated and cannot be reused ).
 
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Old 11-11-10, 01:21 PM
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Replace the insulation board (thats what all that dirt looking stuff is, it has deteriorated and cannot be reused ).
You're right about that. Some particle board was reduced to soil. Is it NECESSARY to have insulation board over the T & G 2 X 6's? Can they proceed straight to laying down the roof without it?
 
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Old 11-11-10, 05:42 PM
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You need it if it is a tappered insulation or you have living space below. Check to see if the roofing material gets thicker as it goes up the roof or around the perimeter. If it does then the insulation is what is giving you the proper pich with a series of A and B wedge shaped panels. If you have living space underneath you should go with a beter insulation than was up there like ISO. If not useing insulaion make sure you are useing short nails so they dont penetrate any exposed cielings in the room.Also if not useing insulation you should lower that board (fascia) to the hight of the deck.
 
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Old 11-11-10, 05:57 PM
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What is the R-value of 1/2 or 1/4 wood insulation board? Does rigid insulation mainly keep the house cool on hot days or is it more effective at keeping the heat in on cold days? My home has a concrete slab foundation. Seems to me a lot of cold comes up through the floor. I've lived in another slab foundation home with an insulated ceiling before and it was always losing heat -- nothing like a previous home that was a raised foundation, which kept the heat in nicely. So I don't know if putting rigid insulation up there is really worth it. I'm mainly concerned with keeping the heat in. I only have about 5 really hot days per year here.
 
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Old 11-12-10, 03:10 AM
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I dont know alot about R values, but I do kno0w you need insulation if you are heating or cooling the space below. I am in Florida and we dont use the heat more than a few days a year, so maybe someone else can answer that one but I strongly recomend insulation. The ISO itself is about $125 per sq (10 by 10 area) ask your roofer what the cost will be to add it, and his opinion.
 
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Old 11-12-10, 05:04 AM
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I agree if they are using an insulation barrier, the rim should be there, but it must make the roof flat with that rise, or you will collect water. You'll need to find out what their plans are.
 
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