Protection for deck PT wood stair stringer on concrete?

[stratfordone]

I'm building stairs from a deck down to an aggregate concrete slab below. Is there anything I should do to my stringers (2x pressure treated pine) to protect the wood to slab connection? So far I havent read anything that suggests they should be wrapped or coated in anything...but I'm concerned that they'll collect water there and rot a lot faster. Should I be worried about this? Any suggestions to make the stringer ends last longer? Thanks!

[SteveBell]

I fasten a crosspiece to the bottom. The crosspiece sits on the ground, and the ends of the stringers are fastened to it. The crosspiece will (hypothetically) rot first, and I can replace it. It's the same idea as putting a rot board at the bottom of a fence.

You can also play around with sloping things so they drain better, if you like. I don't know of anything that will preserve your wood better than what's already there from the pressure treatment. Waterproofers like caulk or tar will just keep the ends from drying out, promoting rot.

[stratfordone]

Ah, that might not be a bad idea. Just to clarify, do you normally use one 2x piece as the crosspiece? (deep enough to completely support the stringers...in this case would probably need to be a length of 2x12). I'm assuming you lag bolt the crosspiece to the slab then bracket the stringers onto the crosspiece? This could be a great solution, just getting used to the concept. Also, in your experience is replacing that crosspiece fairly easy? (obviously, easier than replacing 2 stringers so maybe that doesnt really matter). Thanks for your help!

[Phisherman]

Pt wood will eventually rot and the strategy is to extend this time as long as possible. Any part touching a concrete slab or ground that is end-grain is especially vulnerable. In that case, you can cut "pads" of wood and fasten these onto the end grain. Use a penetrating oil stain. You may also consider metal brackets that keep the wood up off the slab so the end grain can dry out.

[SteveBell]

I haven't had to actually replace one yet, but I suppose I would: * Remove the last couple of treads. * Unfasten the stringers from any support posts. * Jack up the bottom of the stairs enough to get tools under the end. * Whale away at the fasteners until I accomplish the deed.

Deck stairs are usually pretty short, so complete disassembly wouldn't be too horrible.

Some recommendations: * Use stainless steel fasteners, especially near the ground. They're recommended for pressure treated wood anyhow. Whatever kind of fasteners you use, make sure they're rated for use with your PT wood. * If you're putting in a new concrete pad, slope it so it drains away from your stairs. 1/4" per foot is pretty good for concrete. * Put a third stringer down the middle of the steps. They'll feel much sturdier, and they won't break when the husky guys come to install the hot tub. :)

[EXT]

I prefer to cut "pads" similar to what is described above, but not out of wood, but using plastic. Most any thick plastic will do, the thicker the better as it lifts the end grain away from the concrete and water. My preference is to use 1/2" thick polyethylene. Attach it to the bottom of the stringer with stainless steel screws.