Here is my quandary. I have finished a wrap-around deck for an oval above ground pool with one edge up against the house and one open side edge is approx 18 feet. I can put a railing on this side but it would reduce visibility to the rest of the yard and I would like the deck to flow into the patio. So I thought a wide 12' set of stairs would be more appealing. Any reason why I cant go 12' wide on 5 step stairway? Deck is approx 30" high. I was planning on stair railing on each end of the 12' span. Any need of railing midway or can I go the full 12' open? Any pitfalls or issue I should consider?

I always thought wide stairs looked great. They might take a while to build but will look pretty cool when they are done. There is no reason you should not build 12' stairs. Wide stairs can become great places to sit though. You might want to reinforce the them to ensure they will hold ample weight. This might be adding more blocks or adjusting the location of some of the blocks.

Deckman