Last year, I had a new fiberglass shingle roof installed by one of the better roofing companies in my area. Overall, I am happy, but I'm not sure that the drip-edge was done correctly. It seems that water will wick up under the edge and potentially cause rot (I live in a humid area).
I am considering attempting to bend the edge up, so it is more like the previous drip-edge. I think that if I make a wood wedge on a table saw about a foot long, I can push it up under the edge and press another piece of wood at the existing crease to increase the bend. I know that it will flex enough to get a wedge in, since I put temporary spacers under the edge so I could get paint under the edge (roofer left any replacement fascia unpainted).
Is this a good plan?
I pointed out my concern to the roofing company owner, he disagreed. I wasn't sure enough to argue much.
Best Answer
No. Opening up the joint creates increased opportunity for bulk water entering the wall system driven by rain. Capillary action is a less likely source of bulk water penetration. The joint widens behind the metal, the wood’s rough surface lowers surface tension, and the depth of overlap gives gravity a lot to work with.
While a properly formed positive drip edge formed from a wider piece of metal would have been better, the improvement would be mostly the wider material. Wider flashings simply provide more protection. One reason drips are associated with wider flashings is complex profiles add stiffness. The stiffness reduces oil canning of broader sheet metal surfaces.
The construction looks pretty typical for a reasonable residential roofing job and the roofer’s experience with local conditions and intact reputation count a lot more than lay roofing theories. A good rule of thumb is don’t add holes to working roof systems (or enlarge existing holes).
If a large volume of water is coming over the edge of the roof, gutters and downspouts might be warranted.