I'm building an overhang/porch on an upper deck. In doing this I'm attaching several 4 x 4s to the edge of the deck. I'm cutting a notch (sort of a very wide rabbet joint) so they overhang the edge so they'll match a couple of 4 x 4s already there as part of the railing. My home is a stucco house with a textured coat in Southern California.
I've removed the textured coat and ground down some of the undercoat (I'm not sure what it is, but it's as hard as cement). There's apparently a 4 x 6 or 4 x 8 behind this coat that I'll screw lag bolts into as was done on the 4 x 4s used for the railing. My question is, what's the best way to seal this wood against the undercoat of masonry/cement on the house? What type of caulk/sealant should I use around the 4 x 4? Should I apply it to the face of the wood that's coming into contact with the masonry then scew it in place, then add more sealant around the edge? Should I paint the wood before applying the caulk or apply it to the bare wood? I'd really appreciate any help on this. I've had to replace quite a bit of the wood on the deck because of dry rot and I'd like to guard against it on this project.
I would tend to coat the side of the 4 x 4 in contact with the wall with a tar/creosote type preservative like you would for fence posts in the ground. Personally, I would do the painting then caulk with a good silicone caulking like you would use on windows.