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Thread: Concrete piers for deck in sonatubes - How long to dry/cure?

  1. #1
    Join Date
    Feb 2003
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    New Braunfels, TX
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    Concrete piers for deck in sonatubes - How long to dry/cure?

    Not for me, as I poured mine earlier this year before leaving town for a week. But a friend is looking to fill his holes w/ concrete this weekend and start framing.

    Is this possible? How long should he wait before loading them with post anchors, posts and doubled-up beam?

    This will be in Indiana w/ fall temperature between 45 and 60 degrees.

    Thanks,
    Linc

  2. #2
    Join Date
    Jun 2003
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    Portsmouth, VA
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    Linc, concrete hardens to 80% strength (working condition) in a week and full strength in a month. Additives can speed it up a bit, but these are mainly used when pouring in cold conditions. Also, if the sonotubes are in direct contact with dirt this will speed it up as it will pull the moisture from the concrete faster (it also decreases overall strength of the concrete).

    Sorry, but your friend should pour this weekend and frame next.

    Be well,

    Doc

  3. #3
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    Aug 2005
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    I think Don's advise is pretty good. One week is plenty for a simple deck footing with a normal dead load of only 10 lbs/sqft. If you used premix bags of concrete, like Sakrete, this mix may have a very high strength (4,000 lbs) and likely OK in just 72 hours. If so, check the bag.

    -Jeff

  4. #4
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    Gassaway, WV
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    inspectors made us leave the forms on for 24 hours then we could set more forms. I doubt if the decking material was as heavy as our forms. Three days if there is going to be a real load like heavy equipment or vehicles on it.

  5. #5
    Next Day -
    Absolutely no problem. and no additives needed.

    Start framing.

    There's not a concrete guy in all of MN that would not 100% agree.

    They pour footings on Monday, then pour foundations on Tuesday all day long for new homes.

    I have seen masons pour footings in the am and lay up block in the pm.
    That, though is with additives.

    Its standard procedure up here to pour deck footings one day and frame the next. Never has been a problem. Never.

  6. #6
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    Thanks for all the replies guys!

    -Linc

  7. #7
    Quote Originally Posted by Matt Ocel View Post
    There's not a concrete guy in all of MN that would not 100% agree.
    Maybe but, he's in Illinois.

  8. #8
    Next day. I've seen a driveway poured one day, driven on the next day.
    "I love the smell of sawdust in the morning".
    Robert Duval in "Apileachips Now". - almost.


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  9. #9
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    Lafayette, IN
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    Quote Originally Posted by Cliff Rohrabacher View Post
    Maybe but, he's in Illinois.
    He is, but he said it would be in Indiana. I see footings poured one day, foundations the next all the time. For decks, framing is the next day normally. Concrete reaches at least several hundred PSI compressive strength as soon as it hardens, so a light load like a deck is no problem. A 4x4 is just over 12 sq in cross-section, so even if the concrete could only handle 500 psi the next day, that's 6000 lbs you could put on one post--probably 2-3 times the weight of a typical whole (average) deck.
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


  10. #10
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    Deck foundations aside, pouring a foundation or a driveway one day, and loading it the next day are just bad news. They can get away with it because the problems won't be fully appreciated until several years down the road when normal shrinkage helps open things up.

    Unfortunately, residential construction is too hastily 'slammed' together these days. I've noticed a lot more foundation and slab issues like cracks, poorly vibrated mix, rough surface finish, etc., with new masonry than ever before. Commercial work tends to have more scrutinny (concrete engineer services, on-site slump test, lab strength testing, approval prior to loading, etc.).

    A house that was recently built next door to me even had the pour forms noticeably installed out of square. The forms had a bit of a parallelogram look to it. I told the builder. He didn't care and they poured the next day.

    -Jeff

  11. #11
    Join Date
    Jun 2003
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    Portsmouth, VA
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    When I did all my concrete work a couple of years ago I consulted with the SeaBees I work with. The recommendation I got from them, how the Navy does it, is what I posted above. They said the only time they would speed it up would be in emergency situations (and then they use additives). I waited a week for my sonotubes (14 4'x12")and two weeks when I poured my new basement floor (1300 square feet, six inches deep).

    Oddly enough, they said the same thing that Jeff did - builders do it because they can get away with it for now and because time is money. While what Jason said is true about concrete having a lot of strength when it hardens, it is not cured properly and loading it may result in cracks within the concrete. Will this have any effect on the stability of a deck? Probably not. Will cracks in footers affect the foundation poured on top of them. Again, probably not.

    But like everything I do in my woodworking hobby, I strive to make things the best I can. Sacrificing quality for time sometimes isn't the right answer. It's just like how everyone complains about Norm using brads to hold pieces together until the glue sets. Do I? No, I leave it in the clamps over night. So why not do the same here?

    Be well,

    Doc

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