Tile roof

Did a home yesterday, built in 1980 with original tile roof. In the attic, found that they had original blown-in insulation which is long since settled and is about 1/2" thick now. However, they have the reflective underlayment on the bottom surface of the roof.
This underlayment is torn in a lot of places, and I was able to see the roof through it. It appears they did not install sheathing - but laid the cement tiles directly on 1"x8" battens, fastened directly to the truss.
I thought this was not allowed for years… should have sturdy sheathing - like 3/4" plywood, then battens to fasten the tiles onto.
Of course, there are a few leaks… and other issues - like Fed Pacific panels… My client has already cancelled the contract, but I wanted to learn more about this roofing.

I don’t know about Florida, but skip-sheathing under concrete tile was allowed (and pretty common) in CA for many years (70’s to 80’s).

Unfreaking believable. Your client made a great move too walk away from that contract.
Concrete S-Tile was never intended to be water tight. It is intended to be installed over a solid roof decking with a built up hot mopped or cold process roofing membrane which provides the water proofing.
The roof that you have in your photo originally had a cedar shake roofing system installed on the batts and at sometime an idiot installed concrete tile

What type of system are you referring to here? I’ve never seen such an application.

You’re speculating here, and based on what Andrew has posted, you are not correct.

As I stated in my previous post, this was a common practice for a period of time. I have inspected dozens of homes with this roofing system. It is certainly a poor design and susceptible to leaks, but it was an acceptable practice.

I’ve seen several roofs from the 80’s in this area installed over battens. They were in no worse shape than tile roofing on any other type of sheathing. No evidence of leakage and no stains at the eaves, like I find on most tile roofs.

If they change it to a shingle roof, it will certainly cost more due to the sheathing installation.

Well, supposedly, this home has had one owner since it was built. There are no building permits online for any roof work, so I am inclinded to believe this is the original roof. There were water stains in several spots in the attic, plus there are a lot of places where rodents have gotten in and nested. I kept expecting one to jump out!
I can’t imagine how this roof is even close to water-tight. It was actually raining pretty hard during the inspection, and I didn’t see any obvious leaks. I can’t imagine how this roof keeps water out!

you are correct it is never safe too assume. I have too continually remind myself that S.E. Florida is a different animal than most areas of the country and in this case different from areas of the same State. The picture in the original post was taken in an area of Florida that is not in A Wind Borne Debris Zone.
The areas that I inspect have always required a 2 ply roofing underlayment installed over a solidly decked roof.
The first ply is a 30# felt building paper and the second ply consists of a 90# rolled roofing that is lapped 6" on the shoulders and 12" at the head and sealed with hot mopped tar.
With that said some new systems that are getting product approvals which consist of a single ply peel and stick membrane