Question about building on dirt

I need to build a step going up to my deck; it will run along the entire length, but the entire deck is no higher than one’s shins. It seems a waste to pour a concrete footing for this. It’s been suggested that I just sheath the pressure-treated wood supports in galvanized sheet – is that a good idea?

Just bury 2" x 8" x 16" concrete block to set your stringers on.

When I build a deck I dig footings about 2 feet deep, put 4x4 treated posts in hole and fill with cement.

You lost me here. Where are you putting the galvanized sheet metal? Around the pressure treated lumber that you burying?
You are putting in just a single step, 12" wide by the length of the deck? I’d say a 2x 6 or 8 nailed to the existing deck supports to hold up on end of your step, and drive pressure treated 2x4’s 2 or 3’ into the ground every x’ to hold up the front edge of the step.

Check your local building code. Codes vary so widely between municipalities and regions that someone from Minnesota, Oklahoma and California can’t possibly compare notes. You may also (I suspect) have to get a building permit to modify the deck.

That said, it’s not a good idea to put wood in direct contact with the ground as the wood will rot (yes, even pressure treated). The galvanized metal may eventually rust, but at the least, gives water a place to pool and rot the wood. You can get concrete piers that sit on the soil and they are made to carry joists or cross-members.

Pressure treated wood comes in several “strengths” of treatment. Most of the stuff you fine in the Home Depot type stores is the minimum strength and is not recommended for ground contact even though it’s used that way.

I’d go with the concrete piers.

Come on people! He is not building the Taj Mahal! He is putting in a single step. A single step should be no more than around 7" high. To use the concrete piers (which ae over 7" tall themselves) , he’d have to dig holes to set them in. He’d be better off using a few sacks of quickcrete in each hole than doing that, as getting a flat stable bottom on the holes to set the piers is a pain.

Pressure treated lumber has been in-ground proven for 40 years. Galvanized metal is most definitely not created for being buried. Most of the home store PT lumber I see specifically says “Rated for ground contact”. I stand by the advice of using driven 2x4’s as the front support.

CCA has been around that long, but it has been phased out. ACQ is the most commom replacement, and it is not rated for ground contact. The treatment is water-based and will leach out of the wood.

I’d just call the building inspector and ask what he/she likes to see. Left to my own devices, I’d probably find some ACQ-rated hangers and sink them in concrete footers, or cantilever the step off of the deck (going about four feet under the deck) if the framing allowed it.