On-line sources advise that, to avoid leaks, exposed panel fasteners should be installed at panel ridges - never in the valleys. But what about the space under the ridge? Some kind of support must be provided to avoid deformation of the metal. The cross-section detail below illustrates one easy solution.
The 1/4 round wood molding strips are perfect for this job for many reasons:
- They're cheap and readily available,
- They provide solid support for the roof panels along the entire length of the panel overlap,
- The shape of the panel holds the strips in place during installation,
- Splitting is not a problem because the screws pass between the two wood pieces.