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Thread: Tapcon Problems

  1. #1

    Default Tapcon Problems

    One 3' long 4x4 post for a deck railing needed to be anchored into an existing concrete slab. I bought a metal anchoring plate that had 4 screw holes that needed to be screwed into the concrete, and the 4x4 would sit in it and be held in place by 8 deck screws--4 on each side of the plate.

    I drilled 4" holes using a 3/16" masonry bit and used 3" long 1/4" tapcons with hex head. Unfortunately, when I went to screw these tapcons in, they broke in half around 3/4 of the way in. I ended up having to ream out the holes a bit for them to screw into, but they weren't anchored as firmly as they would have been if they had been screwed into the original holes.

    Should I have just pounded in lead anchors and saved the tapcons for brick and block?

  2. #2
    One who lurks Basement_Lurker's Avatar
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    Default

    Why were you using a 3" long tapcon screws to anchor one of those post bases? The base anchor plate is at most a 1/4" thick I believe and you only need to penetrate into the concrete about 3/4" or so. So a 1" tapcon would have done the trick and you would have had more success at actually getting it to screw in all the way. The 3" long tapcons are useless...you'll never get them to screw down all the way without stripping, and using them to secure a 2x4 is a waste of time.

    I only use tapcons when I have no choice because I am afraid of splitting the concrete...like underneath a toilet flange. For anything else, and especially when I have to anchor something wide like a 2x4...I use a powder actuated tool...I bought it out of frustration, and it has been one of my most satisfying tool purchases to date. You can even get the cheapo units (under $50) that you strike with a hammer; I have been told that they get the job done.

  3. #3
    G.C. 22+ years(in 3 states) Old Dog's Avatar
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    Smile Tapcons for post

    Eric,
    You used too long a screw for the application.The drill bit size was correct but the length wasn't.That's why it snapped off.If you put the plate right on the concrete the max length needed was 1 3/4"(I"d use a 1 1/4").Your looking for a min. 1" and a max of 1 3/4" of depth with a tapcon.Easiest way is add whatever your going thru(let's say a 2x4) to 1"-1 3/4".At the min.2 1/2",at the max.3 1/4".(1 1/2"+ min.1"-1 1/2"+max.1 3/4").

    *Next time I would recommend a "stand off" 4x4 post bracket for a concrete application.It raises the wood post off the concrete to keep the bottom from moisture and rotting out.I would Keep a small Simpson "strong tie" epoxy kit in your tool box(good for about 4-5 1/2" anchor bolts).Drop some of that in a over drilled hole,screw in that tapcon,epoxy kicks off,it aint moving...ever

  4. #4
    G.C. 22+ years(in 3 states) Old Dog's Avatar
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    Default Tapcons useless?

    Quote Originally Posted by Basement_Lurker
    The 3" long tapcons are useless...you'll never get them to screw down all the way without stripping, and using them to secure a 2x4 is a waste of time
    If you clearance drill the 2x4 first,use a tapcom drill on the concrete/hollow block next,the tapcom works just fine.Recommend the hex heads,don't strip out as easy.
    A powder actuated gun works good,except when you hit a big piece of aggregate in the concrete!It good on metal stud work,but thats lighter guage metal than a simpson "strong tie" bracket.It would distort the bracket as it went thru.I wouldn't recommend it.(I've had to hit nails with 2 loads many times to set 2x4 bottom plates prior to tightening down anchor bolts.)
    Bottom line,they work fine when they are used properly.

  5. #5

    Default

    Like others have said, too long. I like tapcons and don't like the hilti guns all that much. I've found situations where it will just bust up the concrete below the board.

    Tom

  6. #6
    Licensed Grump GrumpyPlumber's Avatar
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    Default

    Too late now, but they make post brackets that can be dropped right onto semi-dry concrete, they have built in anchors, like shanks.
    "The biggest regrets we have in life are the chances we never took."

  7. #7
    Retired Defense Industry Engineer jadnashua's Avatar
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    Default

    Often on a deep vertical hole like that, you don't get all of the dust and debris out of the hole, so as you tighten things up, you are trying to force the thing through rather than just cutting threads and it breaks. Sometimes, vacuuming out the hole will make a big difference. Plus, unless you were using their drill bit, the pilot may have been close but not exact which, on a hard substance, can make a huge difference. My tapcon experience is limited, I've probably only used a box or so, but have had good luck.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  8. #8
    Moderator & Master Plumber hj's Avatar
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    Default tapcon

    Too long a screw, and debris at the bottom of the hole would be my best guess as to why they didn't bottom out before snapping. Vacuuming probably would not remove the debris, but an air nozzle might. Did you use the proper Tapcon drill?

  9. #9

    Default

    HJ: I used my Bosch hammerdrill with their "Blue Granite" series masonry bits, like I always do.

    JAD: I agree that there may have been debris at bottom of hole. Will try to suck it out better next time.

    Grumpy: This was an old concrete slab.

    Statjunk: I have heard the same thing about those powder-based drivers.

    Old Dog: I will look into this "stand-off" bracket.

    Lurker: This was a 4x4 post I needed to secure.

    Thanks to all. And I will use shorter screws next time.

  10. #10
    DIY Senior Member construct30's Avatar
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    Default

    I never have any luck with tapcons unless I use their bits in concrete or brick. I like the standoff bracket and the six inch anchor bolts with the nut on top. You drill a 5/8" hole, put the bracket in place and pound the bolt into the hole and tighten the nut, put in a couple of short tapcons just to keep from twisting. That is about the only thing our inspectors let us use to anchor posts for a porch roof or deck in old concrete. They usually want holes cut into the slab and proper footings installed unless you can prove there is a proper footing there already.

    mark

  11. #11

    Default

    I never liked tapcons and I believe they state 1&3/4" as a maximum embedment so your 3" was too long.

    For deck posts, ledger boards, vinyl rail anchors I use a roto hammer and SDS drill bits to drill holes up to 1" dia. Then use expanding anchors. If the anchors
    prove difficult to secure the item then I use the Hilti 2 part epoxy with their gun and mixing nozzles. For going into block or brick with voids a screen thimble is available to minimize epoxy waste.

    Holes into masonry or concrete over an 1" I use a diamond core bit without the center bit. I find if I drill a hole the size of the core bit OD in plywood I can stand on the plywood to keep the core bit in place to get started.
    It is also easier to get the plugs out of the bit without the center bit.

    The SDS bits use the hammer function. The core bit no hammer just rotation.
    Ron

  12. #12
    Commercial Plumber markts30's Avatar
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    The powder actuated guns are great for nailing unistrut to structural steel...
    Drives the ballistic steel pin straight through the unistrut metal and abount 1/2" into the IBeam...
    We use it all the time for supporting roof drains, water pipe and waste and vent stacks...

  13. #13
    One who lurks Basement_Lurker's Avatar
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    Default

    Quote Originally Posted by Verdeboy
    Lurker: This was a 4x4 post I needed to secure.
    The 1/4" thickness that I was referring to was the thickness of the bottom part of the post support that actually gets secured down. Unless you are using something different that what I have in mind.


    Power actuated tools take some learning. Blasting out can usually be avoided if you know how and where to use the tool. And you can get nails with washers already on them which gives it even more surface area to hold down. I have yet to have a problem with not being able to nail into concrete because of aggregate, and I am only using charges that are one down from the strongest available.

    It takes 5 mins to drill the sill plate, countersink the tapcon head, drill the tapcon hole, attempt to clean out the hole as best as possible, and then drill the tapcon screw. It only takes 5s to load a nail and embed it. And from my tests, I was unhappy at how easy I could remove the tapcon secured sill plate when compared to one secured properly with nails.

    But this is just my opinion, and trying to argue one over another is as dumb as the perpetual copper vs pex debate....the answer is that they are both better and worse.
    Last edited by Basement_Lurker; 08-14-2007 at 05:30 PM.

  14. #14
    Master Plumber Dunbar Plumbing's Avatar
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    Default

    1 out of every 4 tapcons I've ever used either snapped, broke, stripped, didn't hold.

    They might of been designed that way to make money who knows.

    I went back to the tried and true; pre-drill and bang plastic sleeve anchors in and be done with it.

    It would really suck setting a closet flange and those damn things break flush with no other way to anchor.

    Sometimes they grip too hard and quick....leaving gaps to what you're trying to anchor tight.
    Read what the end of this sentence means.

  15. #15
    DIY Senior Member molo's Avatar
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    I cant stand tapcons. i used some red-devil expanding anchors that worked great. I pre-drilled, then tapped the anchor in, then tightened the bolt in. They were awesome
    "Any American who is prepared to run for President should automatically, by definition, be disqualified from ever doing so."
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