Changing 1 coordinate of a block's location

[lyric ether]

I'm using the location of blocks to add NBT data to them. I'm trying to edit the NBT data of a door, so they take up the space of 2 blocks.
So, how can I add 1 to the Y coordinate of a location so I can also apply NBT data to the top half of a door?

[golden nymph]

Add 1 to {_loc}'s y-coord