improper head lap

[Dave Hill]

Hi Guys,

Anyone have a good explanation for improper head lap, and something I can refer the roofer to? When I see exposed nail heads at the first course, which I feel should be covered by the ridge tiles, I call it out. I don't cite code, just recommend that a qualified roofer further evaluate. A "roofer" says that all houses in the neighborhood are done this way. Great logic!?
Any help is appreciated.

[Jerry Peck]

The installation instructions.

They will (most likely) specify a minimum headlap of 3". That minimum headlap will cover the nails as the nails are likely about 1-1/2" from the end of the tile.

When you are talking to the roofer (or any contractor) who says something like that, simply state "Provide the installation instructions from the manufacturer and whatever the installation instructions state is what is required as a minimum. Please e-mail the installation instructions to me at (...) so we can both review this together and so I can send a copy to my client/seller/agent/builder/whomever."

There is no arguing with the manufacturer's installation instructions.

[Dave Hill]

Hey Jerry, this works for me. Thanks!

[Philip]

You would think that a roofer installing such an expensive roof would understand and follow the nail pattern recommended by the manufactuer. But come to think of it I have seen a lot of exposed nails on such a roof. However, they don't leak.