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  1. #1
    Join Date
    Jun 2021
    Location
    NY
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    2

    Default Please help! General Contractor screwed me :(

    Hello,

    I'm from the United States, NYC to be exact.

    I do carpentry work and I take a great deal of pride in the job being done right. I am very careful with the materials I use and I understand the interactions that happen with pressure treated lumber and metal.

    Right now, I am preparing to build a pergola on the concrete patio of my backyard. I hired a general contractor to come in and cut 4 holes in the concrete, pour new concrete into the ground and install J-shaped bolts to be the anchors for the pergola columns. Everything was going great until they needed to cut the bolts because they installed them too high. They were sticking several inches above this! Very stupid work.

    All of these metal pieces are made of hot-dipped galvanized steel because it is so corrosion-resistant, and now that they've been cut, the galvanization has been totally compromised. I am very, very concerned that these bolts will rust and corrode and that the structural integrity has been ruined. Please see photos below.

    Please help! What can I do? Is there a way to seal the metal off so that it will resist rust and other issues? I can't redo the job -- it cost me $600 and I cant afford to redo.

    Please excuse my ignorance, I am a carpenter and have NO experience with metal, so please go easy on me. I appreciate all of your advice in advance.


    IMG_0204-sRGB.jpg. IMG_0205-sRGB.jpg

    Thank you,
    Kelley

  2. #2
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
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    7,182

    Default

    I'd start by covering up the surrounding metal and only allowing the exposed cut surface to show and then smooth the rough cut surfaces off with a flap wheel on an angle grinder.
    Avoid getting the metal dust on the rest of the metal otherwise it will rust. Also for the same reason as previous, carefully remove as much of the metal dust the idiot generated when they cut the bolt. Some of these grains may be embedded in the zinc so a still fine (brass?) brush may be needed.

    The, get some "cold galv" paint and paint the exposed surfaces - several coats should suffice.
    It's a zinc rich paint that is high protective against rust - not quite as protective as galv but still pretty good especially if it's not going to be disturbed.
    Some so called Zinc rich paints have very little zinc in them - you will definitely know it's a zinc rich paint because cans of it will weigh a lot more than regular paint.

    Send a copy of the receipt for the Cold Galv to teh contractor and request he pays you for it,

  3. #3
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    6,446

    Default

    Hi woodworkinggal,
    Welcome to the MetalWorking forums.
    Most of us reading your posts are Aussies and that because the Forum is aussie based. Saying that we will do our best to help but know we are not up to speed with US codes and practices.


    They are a great bunch here very helpful and supportive of one another.
    If you explore our pages you will find bits and pieces of interesting things all over the place.

    Go to the FORUM at top LH corner and click on it.
    A drop down menu appears and you can select Forum Home at the top of the drop down. Scan down the pages to look at what we have.

    Please read the Terms of Use -our Rules - pretty standard for many forums these days.By joining the forum its automatic that they apply to you as a member

    Normally the soft ware works so you can't post pics or links until 10 posts are made ( or such links and pics are cleared by a mod)

    Its an anti spam thing.

    As someone who lives in the NE tropical area of Australia I have battled with corrosion for the 27 years I have lived here and can offer some advice. For starters, that galvanised box needs to be insulated from the touching the cement. Cold Gal alone will not be enough.

    I have similar galvanised units and can tell you that electrolysis corrosion will occur in that tight area between cement and galv unit base.
    A thin sheet -even if it is only a small nylon cutting board will greatly reduce that electrolysis .

    The bolt if it was once galvanised is no longer protected.The photo seems to show an oxy cut and the nut and washer looks like the Galv has been burnt away. I would be removing them and replacing with fresh galvanised nuts and washers . The embedded thread can be coated the the product Never Seeze( its nickel based ) which should be readily available stateside. While not cheap it is not overly expensive. Its better to do it properly now before the posts go in.

    Welcome to the Forums.

    Grahame

    As per what BobL said a couple of coats of cold gal won't go astray.

  4. #4
    BobL is offline Member: Blue and white apron brigade
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    Perth
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    Default

    Quote Originally Posted by Grahame Collins View Post
    The bolt if it was once galvanised is no longer protected.The photo seems to show an oxy cut and the nut and washer looks like the Galv has been burnt away. I would be removing them and replacing with fresh galvanised nuts and washers . The embedded thread can be coated the the product Never Seeze( its nickel based ) which should be readily available stateside. While not cheap it is not overly expensive. Its better to do it properly now before the posts go in.
    .

    Rather than oxy it looks like an abrasive thin kerf cutting wheel cut to me. The Galv on the nut is covered in metal dust which will rust but its probably OK but replacing them would be a reasonable option.

  5. #5
    Join Date
    Apr 2021
    Location
    Adelaide
    Posts
    205

    Default

    Quote Originally Posted by woodworkinggal View Post
    Please help! What can I do? Is there a way to seal the metal off so that it will resist rust and other issues? I can't redo the job -- it cost me $600 and I cant afford to redo.
    I feel your pain Kelley. I think that, as suggested, cleaning up the metal dust and painting with cold galv is your best bet.

    Are those brackets on an area that was already concreted? If you need to add more brackets, you might want to try dynaBolts. I think they are at least as strong as the brackets you have.

    What is going in to the brackets? The bottom end of a wooden pole? If you have that trouble again, try drilling a hole in the bottom of the pole and sit the pole over the bolt. Doesn't fix what you've got though.

    I hope the rest of the build proceeds without further incident.

    Regards
    Jack
    Attached Images Attached Images

  6. #6
    Join Date
    Nov 2007
    Location
    melbourne australia
    Posts
    3,228

    Default

    I agree with using cold gal on the cut end of the bolts. I also agree it’s an angle grinder cut rather than OA. I can sort of sympathise with the contractor. It’s very difficult to set a cast-in bolt to an exact height. Better to set it too long and trim it down. But he should have made neater cuts and treated the cut ends against corrosion.

    Jack,
    The bolts in question are J bolts that have been cast into the concrete pads. No dynabolt will provide the equivalent pull-out strength of a cast-in j bolt.
    Chris

  7. #7
    Join Date
    Nov 2008
    Location
    North Brisbane. Qld. Australia
    Age
    70
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    1,511

    Default

    I'm wondering if a Bitumen Compound applied to bolts and brackets after the cleaning and cold gal will help. Maybe even under the brackets? Ignore me if I am am offtrack.
    Nev.

  8. #8
    BobL is offline Member: Blue and white apron brigade
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    Feb 2006
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    Perth
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    Default

    I assume wooden t posts are going onto those brackets/stirrups?
    If so, I would have considered drilling holes in the bottom of the posts rather than cutting the bolts.

  9. #9
    Join Date
    Apr 2021
    Location
    Adelaide
    Posts
    205

    Default

    Quote Originally Posted by jack620 View Post
    Jack,
    The bolts in question are J bolts that have been cast into the concrete pads. No dynabolt will provide the equivalent pull-out strength of a cast-in j bolt.
    I agree but the weakest link looks like the bracket not the J-bolt. In the end, a DynaBolt may well not be sufficient, but it's worth a look.

    Jack

  10. #10
    Join Date
    Apr 2012
    Location
    Healesville
    Posts
    2,129

    Default

    If you didn't paint the J bolt it would out last those brackets and the structure above it and probably the house also.....you are worried about nothing....

  11. #11
    Join Date
    Nov 2008
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    North Brisbane. Qld. Australia
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    Default

    The brackets do seem to be a bit on the flimsy side. No idea what the building regulations specify for your location though.
    Nev.

  12. #12
    Join Date
    Nov 2007
    Location
    melbourne australia
    Posts
    3,228

    Default

    Looks like a standard pergola post bracket in the US. https://www.fastenersplus.com/produc...se-Zmax-Finish
    Chris

  13. #13
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    Quote Originally Posted by jack620 View Post
    It’s very difficult to set a cast-in bolt to an exact height.
    It’s actually pretty easy, string line if you’re old school, laser if you’re a bit more tooled up

  14. #14
    Join Date
    Jun 2021
    Location
    NY
    Posts
    2

    Default

    Thank you all so much for the info!!! I just ordered a couple of cans of ZRC Cold galvinizing compound in the spray form.

    Forgive me if this is a stupid question, but what is the best way to clean metal dust off of these surfaces? Soap, water, and a rag?

  15. #15
    Join Date
    Dec 2011
    Location
    Lancaster, Ohio, USA
    Posts
    100

    Default

    If Cold galvanize is good and bitumin based coatings are good, why not do both. Belt and suspenders approach.

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