Looking for Frost proof stair footing solution
Hi,
As title suggest, been trying to resolve a to code frost proof (WI so 48" or greater depth) stair footing solution for where the stairs touch the ground.
Oddly we dont need a full pad (just a open "level" area 3x3 at base of stairs) and a frost depth footing.
Given the composite decking i want to use i have a lot of stringers 6-7 for a 48" wide stair 5'10" of elevation.
My goal or concern is how to within reason support that many stringers in a way that avoids any wood touching ground surface, i really don't want to have to do or redo anything for a verry long time.
I have considered
- concrete monolith 12 x 48 x48 maybe flared base for additional frost protection (ton of work and messing around with concrete)
- two sonotubes below grade tied with reabar supporting basically a concrete beam so you have a continuous landing pad for all the stringers (less concrete than monolith still alot of work)
- two helicals sunk to or just below grade low profile wood beam or similar (con wood touching grade or below i know could bed in gravel)
- two helicals junk to or just below grade, galvanized steel tube/beam to land the joist on (plastic or tape insolation between wood and metal)
I am using hefty ground/screws/helicals for the rest of the deck footings that go down around 6-7' so already have a contractor that will come for those.
I'm just sort of stuck in a catch 22 trying to figure out a good solution to probably overkill do it once and never again solution to frost proof stair footings. what have you all seen or done?
(also the stairs do not need to support a hot tub)