Part of the gutter extension that went across the carport roof was blown off and I want to secure it better. I have what I would need but am wondering if I can ask how to make sure that the screw(s) that I put in the carport roof don’t leak water down into the carport. The carport roof is normal black shingles.
Any advice on how to screw things into the carport and still make it waterproof?
Brace yourself for the onslaught about puncturing the shingles in any way. However, you can use a dab of roofing cement over the screw heads to seal it off. You can buy roofing cement at the local home stores in cans as small as a quart as you will use so little of it but it always comes in handy to have a little hanging around. You will be able to see that from a distance if you can put up with that. You can also use a high grade exterior caulk but if it is exposed to heat from the sun it may require touch-up every year or two.
If you would like a less visible, and potentially less damaging method, is to use brackets which sweep backwards. You can gently lift the edge of a shingle, slide them in, secure it with your screws, use a dab of roofing cement over the screw and set the shingle back down over it. In this way you have not punctured the top, exposed surface of a shingle.
If you are unable to find brackets that are fashioned to do this you can easily create them from a short, narrow roll of flashing material. You can paint it to match the gutter to better conceal the bracket.
I would not recommend to screw anything thru the roof. We have a lot of sun rooms here in Georgia where the downspouts from the upper roofs dump down on them. Not good since most of the time they are only 3 to 4 /12 pithes with shingles and no ice and water shield underlayment. If you have a picture, that will help. I assume the DS extension is going with the pitch of the roof and not sideways. I install the downspout going down to the lower gutter and install a A elbow going into the gutter. I cut off the bottom 3 inches of the elbow to prevent debris from being trapped where the bottom of the elbow meets the lower gutter. Run a bead of caulk where the top of the gutter joins the elbow. Pop rivet where the DS extension joins together if longer than 10 feet and more pop rivets where it joins the elbow from the upper downspout. It’s never good to use long screws on downspouts since it will catch debris inside of it. Then shove a caulk gun under the extension every 4 feet and squirt some caulk out to glue the bottom of the gutter to the shingles.