I have an existing galvanized roof that is in need of replacing. The roofing sheds away from a second story which has Masonite t-111 siding. The junction with the Masonite has been tarred so I can’t tell how it is flashed.
The flashing, if any, must have caused a problem since it has been tarred over.
I need some advice as to how to properly flash the new roof to make the junction leak-proof. I will be using galvalume standing seam metal 36 inches wide.
Replies
Your headwall flashing needs to be up under the siding. That means that you need to :
A- remove it, flash, and install new back again(Which is probably a good idea since you don't have the best siding in the world anyway and you might discover other things to fix while in there.)
or
B- cut it at about two inches above the roof surface, free it up and slide the new flashing up under it, and renail.
or
C- Since this is a site sponsored by Fine Homebuilding, we don't normally discuss C but without recommending it, I will discuss it [wink].
I think this is similar to what you have now and why it failed and needed tarring. Occasionaly, you can squeek by with ignoring the rules. You need to always keep laps facing downhill so water will always drain down instead of getting caught. Sometimes a headwall flashing in low cost housing is applied over the siding in an adition situation with a bead of caulk under the top edge and fasteners hold it in place. Sometimes this cheep shot is hidden with a 1x4 set in a second bead of caulk near the top of it.
I'll bet that is how your current flashing metal is installed and the reason it failed is twofold. One is that it is in tar which will dry and crack after a few years. The other is that it is attached to Masonite. Not much sticks to Masonite and water deteriorates the stuff. It has a lot of movement and it doesn't hold fasteners well. Allll of this would stop any flashing applied over it to break free faster then almost any other place.