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I have a customer who has a tar and gravel roof, and a tongue and groove ceiling. I anticipate that the existing insulation is in bad shape and will need to be replaced. She currently has 2" insulation underneath the roof. I told her that she will more than likely need to replace the insulation with 4" ISO insulation, but she says that she wants to re-use the old stuff if the roof is in decent condition. I was under the impression that if you tear off a roof, you have to bring it up to current code which would be R-24. Am I wrong?
 

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It would depend on the building codes in your area. The old insulation can be reused if it's in good shape. But how often is the insulation in good shape if the roof needs replaced? You could add new insulation on top to bring it up to the building codes. How much would it really save by leaving the existing insulation and adding additional layers or just replacing it all?

Assuming of course you could actually get the existing bur roof off while leaving the existing insulation in a decent shape.

I'd just explain that if the insulation could be reused it may not be the best course of action.
 

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3.3 in iso is code in Dallas.. and if there is insulation in the attic space that counts too. Its possible they have 12 in bats in the attic and 2 inches on the roof.. that would give them enuf r value to pass.. However, that code is for new construction. Reroofs are different, If I remember correctly, you don't have to bring a reroof to code.

If its an insurance job the ins only pays for it if the policy has a code upgrade endorsement.
3.3 in is all you really need, anything over is a waste of money imo. Especially if the windows, doors and walls are not insulated well. 5 inches is for refridgerated spaces.
 

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Can you do us a favor and video tape the look on your crews face when you tell them they are going to have to reuse some of that iso?.. lol...

Seriously though. I had a customer like that who wanted to save every single penny he could by making my crews job a 100 times harder. Explain to your customer that she has a TAR AND GRAVEL roof... and it would cost less to just buy brand new iso vs making the crew pick it off the old. Or if she is hell bent on keeping it... eliminate the tearoff all together, remove the loose gravel, throw a recovery board or a 1 in iso down and go over top of it. Everyone wins.
 

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It could be a perlite or fiberboard insulation under, then it's possible to strip it off and reuse. Not the best idea but it does work.
 

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So your saying its easy to get a asphalt off perlite? Or your saying if there's iso under a hd board then its possible.....

Oh btw 1985 I guess I just totally resaid what you had already said about how to re do the roof.. my bad.. didn't read all the comments first.. ..

If a tar and gravel roof is leaking or beyond repair...the iso is going to be wrecked. Even if its dry...it most likely was wet at one point and therefore ruined..

I've stacked old under new just to give the roof a higher center.. and or level low spots.. but it doesn't provide any r value...
 

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So your saying its easy to get a asphalt off perlite? Or your saying if there's iso under a hd board then its possible.....

Oh btw 1985 I guess I just totally resaid what you had already said about how to re do the roof.. my bad.. didn't read all the comments first.. ..

If a tar and gravel roof is leaking or beyond repair...the iso is going to be wrecked. Even if its dry...it most likely was wet at one point and therefore ruined..

I've stacked old under new just to give the roof a higher center.. and or level low spots.. but it doesn't provide any r value...
Well no it's not easy to get asphalt off of perlite, unless it's two layers and they are screwed down.

Anyway most of the time any type if insulation will be worthless under existing roofs, I haven't replaced many roofs because the owners felt it was time and wanted to do it *before* they had problems :)

New insulation is the way to go.
 

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agreed. Roof replacement is only an option when water is pouring on their heads. Preventative maintenance is a waste of money.????? lol:thumbsup:
 
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