New Roof?

Old 04-16-04, 05:15 PM
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New Roof?

I have an interesting situation and was hoping for some advice. I have a flat top roof over a sunroom which has leaking and is in genral disrepair. I am hoping to lay a new roof over top to avoid hassle and time.

The current roof is flat and consists of rolled asphalt. I want to lay 2x4 cut to a slope over 9 feet and lay new 3/4 plywood over top and lay new rolled asphalt over this. I have a few problems that I don't quite know how to answer.

Is there any danger of moisture build up in such a small area?
The sides of the roof have no eavestrough, do I have to slope the edges in for water run off?
Is there a minimum pitch that I have to worry about for run off and the use of rolled asphalt?

Any advise on this would be appreciated.
Old 04-17-04, 05:28 AM
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3/4" ply seems a bit too much to me. If sleepers are at 24", I would think that 5/8" (or 9/16" OSB) would be fine. Technically, you don't need to vent as the old roof acts as a warm side vapor barrier.....I would drill a few bird holes and screem them anyway. The roof drains at the eave, not the sides. Minimum slope of 1/4" per 12'. Personally, I would not trust rolled roofing in this case. I would go with a single sheet of EPDM, glued dowm. I'm sure you can find a local roofer who will cut your piece off of his roll. Some distributors will cut rolls.
Old 04-17-04, 06:38 AM
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I wouldn't lay a new roof over the old unless you know that the existing roof structure is in good shape. If it's been leaking and is "in general disrepair", there's a good chance you have wood rot.

The amount of slope you need depends on the amount of rain you have. Do you also have to think about snow loads?
Old 04-17-04, 09:46 AM
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With Dave here . Think Id want to check the wood that is up there now first then put on the new wood and ply the way you said.

Old 04-21-04, 04:43 PM
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Thanks for the advice on my roof. I have had opportunity to investigate further and talk to a few contractors. Between the two I now know the best route to take.

Again Thanks

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