In order to replace that shingle(Name : A), what do I need to do ? I know I need to pry apart the torn one with the one just above covering it(Name : B). But in order to pull out B I have to pry out the above one covering it(Name : C), and so on. Does that mean I have to replace the entire ridge of shingles just to replace A ?
Also HD only carries normal shaped shingle, do I just cut out the HD shingle to match the torn hip shingle (A) ?
I also found there's some sort of leak after the huge snow storm this past winter (In Maryland). I went up to the roof(I walked carefully so not to damage the shingle) and found a few roof nails exposed ?!! I found mostly nails exposed on the top of the hip near the roof ridge vent. I suspect the leak is coming in through the nails. But upon careful examination I concluded that there is no missing shingle that could have broken away by the snow or something. So why are the nails exposed like that ? Could it be the black sealant that used to cover the nails just gave away after the snow storm ? I'm puzzled.
Do I seal those nails with generous amount of Henry 209 sealant ? Also if I only use a little of this black sealant can I seal it and reuse it later ? I do this with normal caulking - at the end of a caulking job I squeeze a little more out of the tube and make sure it covers up the tip.
We'll start with the easy one. If you have traditional tab type shingles, yes, the caps are cut out of a full size shingle, 3 caps per shingle. I could explain how to cut them, but if you look at the package, it will show you. If you happen to have architectual shingles, caps are sold separately, three per sheet, and they are perforated, so you simply bend and separate them.
In regard to the bottom cap on the hip, depending on the age and condition, you may be able to carefully lift the one or two caps immediately over it far enough to be able to get a nail puller under them, and pop the nails up. If so, you can then insert your new cap or caps, and hold the one above it up while you nail it back in place. You can usually work a putty knife between them, CAUTIOUSLY, and separate them. The problem with caps though is that they are obviously bent, meaning that the surface is stretched when they are installed, so they can be finicky. If it's a short enough run, you may decide to simply replace all of them.
But, based on the second part of your post, it sounds as if you may be getting close to needing a whole new roof.