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Hello,

I inspected a commercial roof today. The existing membrane is a torch on cap sheet. I've attached a picture of how a portion of the roof has started to crack. I've been asked to give an opinion of how much longer the roof is expected to last for. Has anyone seen this type of cracking on a torch membrane and are there any opinions on how soon it should be replaced?
 

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How long it will last depends on how many layers are under the cap sheet, since that cap sheet isn't keep much moisture out. I'd be planning on a replacement soon.

I think the cap sheet cracking like that is more common in the APP mod bits as opposed to the SBS mod bits. Too much heat when torching? IDK we don't do any torch downs. In my experience the SBS blister and have more granular loss.
 

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It appears the membrane is crazing only at that location. It also appears that this location holds water. which makes sense because the water heats up and magnifies the sun then causes this type of condition. Easy to remedy. Install a good silicone coating system at this location at about 2 gallons per square. that will help keep the uv and heat off the sheet while also being quite resistant to ponding water. If the rest of the roof looks as good as it appears to in the picture (not including the cracked/crazing area) you may consider coating the entire roof system. Help extend the life of the roof.
 

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Lifespan

It seems like this roof is in bad condition. Try and let owner know it has exceeded its life, that said, it looks like the cap sheet was overlapped and nailed down?
Not torched. In the section that is cracked if not water can be pushed out of those cracks, 3 course the whole area with mastic and then fabric and then more mastic, and then silicone... you might even want to gravel till rejection in this area too.
 
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It looks like you've had quite a bit of moisture infiltration in that cap sheet, which is responsible for the cracking. Your best path forward here depends on how extensive the cracking is.

If the cracks are confined to the portion of the roof shown in the photo, I'd recommend using a siliconized roof coating to prevent further cracking.

If the cracking is consistent across the entire rooftop, I would recommend replacing the cap sheet soon, as the cracking is probably going to get worse, which could undermine the roof.
 
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