Expert: Mark Sundberg - 7/15/2008

Question
Hi Mark... HELP!! I recently contracted with a qualified roofer in Phoenix to re do my underlayment under my concrete
tiles.. NOTE: I HAVE NO LEAKS!! I did have a problem that was recently fixed but when I was getting quotes for the repair all the roofers (4) that I had out told me that since my roof is 17 years old I should really think about
replacing my underlayment & valleys etc... No one looked under my tiles just made that suggestion due to the fact my roof is 17 years old with the added Phoenix heat... It will cost me $8000 and thats money I could leave in the bank. but I am a proactive person but am I jumping the gun???


Answer
Aloha Cid,

I understand your reluctance to spend the extra money. And it's possible it may not be necessary. However, that can only be determined, if at all, by removing the entire existing tile and inspecting every bit of the existing underlayment and flashing. Unfortunately, as with most things, it's not the strongest or best component that counts, but the weakest component. No matter how much you reinforce most of a chain, it's still that one weakest link that controls how much the chain can hold. Same with roofing systems. The new tile might be fantastic and last another 40 years (By the way, why are you replacing the existing tile anyway, if you have no leaks or other problems with it?), but that won't do you much good if the existing underlayment and/or flashing fails in 15 years, you'd still have to pull up the new tile and the existing underlayment and flashing and put down new and then reset the new tile. That's likely to cost you several times what just replacing it now will.

Then again, if you don't plan to be in the house for another 10 to 15 years, maybe it makes no difference, at least not to you. However, it should make a difference to whomever buys or inherits the house and they are either going to pay more for the better roof / less for the not so good roof or your heirs will thank you for saving them the cost / curse you for leaving them a big expense.

Personally, I'd go with replacing the existing underlayment and flashing. Just removing the existing tile is bound to damage it some. Of course, you could go half way, have the roofer remove the tile and then inspect the underlayment and flashing and replace what's bad. I doubt you will find a roofer that will do that, because they would be running a high risk of possible failure if they miss something. It might not cost them anything if it's 5 or 10 years down the line, other than a bad reputation and the knowledge they had done it badly. And it's really difficult to tell just how much underlayment is worn. It might look OK on the surface, but be cracked or worn on the underside. And just the inspection is going to cost you, at least if they do a good job of it.

I'd spend the money. As I said, if you can get the roofer to go along with it, maybe consider inspecting the underlayment when it's exposed and if it looks very good, almost brand new, maybe consider not replacing it.  However, I'd only go that route if the underlayment was really was new looking with no damage at all or very localized damage.

The problem is a leaking roof can be a real disaster. It could be just a small leak that leads to mold growing and health problems that are difficult to trace or rot and then structural damage that's often very expensive to repair. Or it could be an obvious leak, one that ruins an entire ceiling and maybe walls as well as your furniture and furnishings below. And you'll never know when. Peace of mind is a valuable thing. New underlayment may not 100 stop any possibility of leaks, but it will do as much as one can. Going half way, well, it's half way, half-a** so to speak. Consider how well you would get on with just one buttock.