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Decks/setting deck posts


hi, can you please tell me the correct way or code way to set posts for an upper deck (second floor)to a concrete patio below. i want to bolt them to patio , but maybe have to dig to 3 ft.(FROST LINE)to set posts. deck will be apprx. 30 or 40 ft.x10 ft. with a 4" patio slab. thank you very much for your help! don d. (ps.- the deck will be attached to the house)

Hello Don,

    First off, thank you for the question. Please accept my apologies for taking a little long to respond. I was away for a few days (a rarity), and stuck without any internet service. :)

    You must always go down past the frost line in your area, which can vary quite a bit. You should always, of course, check with your local building department for minimum depth & diameter requirements.
    The way we usually approach this scenario, is to get the ledger, the 2 end joists, and a couple more joists here and there tacked in level & square BEFORE marking & cutting into the concrete. With a few temp posts placed out of the way of the footings, you can temporarily support a temporary girder, or save a step and temporarily support all or half of the permanent one. Make sure you measure everything accurately. Then you can plumb down from various spots to find exactly where you will want your posts & footings to fall.

    Next, mark each footing location on the concrete patio by scraping it with a blunt metal point of some kind. Make the lines of all sides of your square marks run long so that you can see them easily while the wet saw is making it's mess. Rent a gas-powered wet saw and diamond blade to cut a square hole in the slab for each footing. Make each cut a few inches longer than the square size so that the slab is cut to depth at all 4 corners. Then dig your cylindrical hole down a couple of inches deeper & wider than the minimum local requirement. Near the top, taper the soil of that round shaped hole up to the square hole that is the bottom of the slab. Get your footing inspection, fill with concrete, smooth it level or very slightly higher than the patio surface (Take the time to fill the over cut lines with some of the slurry or "concrete caulk" them later...You don't want any water getting in and freezing, making it crack later.). Let it set a day or few, re-measure, re-plumb, & mark, then drill and bolt your post anchors in place. Galvanized wedge type anchors work nicely. Your posts and anchors will probably be 6x6 for a 2nd story deck.

    By the way, if your line of footings happens to fall right near the edge of your existing patio, you may be able to avoid cutting holes by sneaking under the edge to dig.

    Let me know how it goes or if you have any other questions. Also, if you are interested in using the space under the deck, and have thought about maybe doing some type of rain-free situation, let me know. I can advise on that as well.

Best of luck! :)
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Michael Romano


I can answer any questions relating to decks, porches, exterior stairs & railings, walkways, access ramps, pergolas, deck roofs, screen rooms, etc... These may include design ideas, footing to framing design & construction methods, various species of woods vs. composites & pvc/vinyl materials for decking, skirting, or railing applications. I also have expertise in various rain-free systems for under-deck storage & living spaces.


I have designed and built decks and many other types of outdoor structures for over 25 years for my own home improvement company. We also perform many other types of home improvements, including window & door installation, molding & trimwork, siding, basement finishing, siding, etc. Our main love however, is decks!

NADRA - The North American Deck and Railing Association. Several Small Business & Home Improvement Contractor Alliances & Associations.

I have written several articles over the years for,, and many other deck & construction related websites.

High School graduate. 2 years of Mechanical Drawing & Architecture classes. Vocational School graduate. 2 years of Construction Technology & Carpentry classes. Many years of reading, researching, and application in the real world.

Awards and Honors
I am certified by several decking manufacturers for expert application & installation of their products.

Past/Present Clients
Mainly local residential clients, and occasional commercial clients, including restaurants, nightclubs, office buildings, etc.

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