Tear off two (2) existing roofs, or re-roof over the top?

Old 01-30-11, 09:59 AM
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Tear off two (2) existing roofs, or re-roof over the top?

Hi, thanks for your time. I'm supervising some work in an old building with a pitched roof, maybe 40'x 80'. The roof slopes along the longer dimension with at maybe five degrees towards a drain, so along that length it probably drops two feet.

We have numerous leaks, and have had a couple re-roof estimates. One vendor took a cross section of the roof, and showed me some old sheathing from the two existing layers of roofing that were moist to the touch.

I've attached a crude cutaway diagram of what he showed me.

I have a feeling the only way is the tear-it-off-and-start-fresh method, which is going to put us back 30-50K. However, I just wanted to confirm or at least solicit feedback of any kind.

Also - we have numerous roof penetrations, including an old chimney that no longer services any. There's also a small (16" or so) parapet running the long length of the roof, bisecting it, and the previous layers go over it. Should we knock that parapet down to level with the roof?

Appreciate advice.

Old 01-31-11, 12:47 PM
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Roofing adds considerable weight, you may not be able to put on a third layer

Also, going over the top is usually not done if the existing roof has issues, which you say this one does
Old 02-09-11, 07:45 PM
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The best thing to do would be tear off the existing roofing down to the sheathing. As you've already stated the roofing is wet so you can bet the sheathing is also wet in certain areas and possibly beginning to rot. There is no quick easy cheap fix for this particular situation.

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