I have a circa 1976 aluminum patio door that I want to replace. The door opens onto a deck. I'm pretty sure it has nailing flanges on the top and sides. My question is-will it have a nailing flange on the bottom? If there is I don't see how I can get the door out without dismantling the deck.
Typically you have to cut the flange and just leave it attached. Use a grinder with a blade for cutting the aluminum and lay a piece of thin material on your deck so that you don't scar it up. I'd remove most of the other flange (sides and top) and then tackle the bottom. If removing the siding is a pain, you can cut the top and sides out as well.
A sawzall with a short metal blade is often effective as well.
I've never seen any kind of flange on the bottom door sill and I've installed sliders back in 76 and a couple of hundred since then. (That's 1976 not 1876). There might be a screw or two down through the sill and maybe some caulk under it. HS.