I have a set of pressure treated stairs that lead from ground level up to a wooden deck, providing access from the pool to a water slide (salt water and chlorine). I originally built these stairs about 10 years ago using galvanized nails to secure the stair treads.
Over time the galvanized nails rusted and eventually split the stringers. I replaced both about 4-6 years ago using deck screws. The deck screws didn't last long at all, split stringers and rusted screws, I replaced the stairs again, about 2 years ago. This time I used stainless screws.
I've noticed that the stringers are splitting yet again. When building the stairs, I predrilled every hole for the screws, even removing the tread when drilling to make sure the hole was deep enough to cover the length of the screw. The treads are not loose yet, but I only see it as a matter of time. The slide stairs are still plenty strong, just aesthetics at this point.
I live in the US, Atlanta, GA area and we did see a good number of frozen days this winter as well as snow, I don't know if that helped in the stringer demise.
I'm thinking of rebuilding another set of stairs (no direct exposure to pool water, but limited access to sun), whose stringers are split to hell, and I'm looking for some tips to make them last longer.
I took a good look and noticed that only the center stringing is splitting like this. The left and right strings have the same number of screws and the exact same placement. I think they are just a bit less exposed.