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As I mentioned in an earlier thread, I am building a deck very low to grade. In some spots it could be sitting on grade. I have always lagged a band joist to the house and sunk posts below frost line. One guy is telling me to forget all that and just set the joists on patio stones or PT 2×6 sleepers on grade. Theory is the whole deck can just float. What are your thoughts?
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Mark,
the problem here with footer discussions is that different areas differ in requirements. What is necessary in Ohio is totally different than what is needed in Texas for instance.
Pete
*I live in an area that's as about as tough as any for footing (-30 to 105, mid-winter thaws, fall/spring freeze-thaw cycles, clay soil, rain/snow). Building a deck 'on-the-ground' is quite common and successfull. Most seem to use "ties" as bed sleepers surrounded by 6"+ of compacted gravel to hold them in place and to promote drainage. The sleepers can be pinned in place with long galvanized spikes, or 1/2" galvanized pipe The deck floats on the sleepers.
*Floaters are fine except if you do need to tie a permanent structure in. Are their stairs entering the house? These could rack, twist or break apart with heaving. I would also be nervous of any deck more than 18" off the ground without a footer. This could also rack or twist apart.If you build close to grade, be more concerned with rotting wood. Get the wood and soil as far apart as you can, even if you use pressure treated. There are pre-formed pier blocks you can use to build on. They are pricey, so other concrete blocks can save a few bucks. Either way, consider using a rubber/asphalt type of 'flexible flashing' material between the wood and concrete. This stuff can be bought in 6" wide rolls and is designed for flashing window and door openings. It is an easy and inexpensive way to hydraulically separate the wood from the concrete.
*Back in the 80s I built about a hundred of these 10x12 yard barns. The floors consisted of 4x4s with PT tongue & groove decking. We sat these on either a base of gravel or patio stones to level the floor before building the rest of the barn. I never heard a complaint about doors twisting out of align or windows sticking due to frost heave. We have some pretty cold winters here in Ohio. I still see many of the barns I built to this day and none show any signs of uneven settling.
*Couldn't the steps be secured to the deck but free floating from the house?
*usually you do it the reverse, they hang on the house and "sit" on the deck ("sit" can mean loosely connected or just gravity - design would dictate). If only one step was needed, it would just be a structure built on the deck. These decks shouldn't be attached to the house - you wouldn't attach a sidewalk to the house, would you ?
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As I mentioned in an earlier thread, I am building a deck very low to grade. In some spots it could be sitting on grade. I have always lagged a band joist to the house and sunk posts below frost line. One guy is telling me to forget all that and just set the joists on patio stones or PT 2x6 sleepers on grade. Theory is the whole deck can just float. What are your thoughts?