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  1. #1
    Join Date
    Feb 2008
    Posts
    43

    Default Earthquake-Proofing Anchor Tips - Concrete Drilling & Nailguns

    I'm planning to seismic retrofit my basement and looking for tips on making the process as easy as possible. I have a lot of clips to install!!

    I worked with a structural engineer who drew up the plans which involve the installation of Simpson A35 clips to attach the sill to the rim joist and Simpson UFP plates to attach the sill to the 7.5" concrete wall.

    My anchor related questions are:

    1. The A35 clips are each installed with 12 x 1.5" 8d nails. Rather than swing a hammer 12,000 times, is there a nailgun I could rent that would be low profile enough to get into the 8-9" of space between the sill and the subfloor? I've used finish nailguns, but not framing nailers. I assume lining them up to shoot into the hole of a A35 plate is fairly easy?

    2. The UFP plates require 1/2" 0-expansion anchors embedded 4" into the concrete. The concrete wall is old (1914) and brittle. When I've tried drilling smaller holes (3/16") in the past with an electric hammer drill and tungsten bit, either I hit a hard pebble that the drill bit doesn't like, or the concrete between the pebble crumbles and leaves a bigger hole. I've never tried drilling a 1/2" hole before - any tips on type of drill/bits etc? Is there a "Powder Actuated" gun I can rent that would shoot bolts like this?

    Thanks in advance for any tips you can pass on!
    Cheers,
    -Brett

  2. #2
    Join Date
    Aug 2007
    Posts
    6,481

    Default Re: Earthquake-Proofing Anchor Tips - Concrete Drilling & Nailguns

    1 - You'll do best with a palm nailer, rather than a nail gun. A palm nailer is a ball, approximately 4" in diameter that you strap to your hand. It has a "beak" on it that is the hammer. This is a device for driving nails, not shooting them. What that means is that you'll buy a box of Teco nails (joist hanger nails ) and hold them with one hand and then use the palm nailer to drive them in with the other, just like using a regular hammer, only the nailer is pneumatic.


    2 - Hammer drills will suffice, but they really are not adequate to drill large or deep holes in hard media such as concrete. Drills using a cutting action (even hammer drills ) to create a hole, and this doesn't work well with stone and masonry products. A better tool is a roto-hammer. A roto-hammer is larger than a drill so it's got more kick to it to "chisel" it's way through the material. You can rent these at any rental yard for a reasonable rate. You can minimize the rental period if you go around the house and install all your straps first, then go rent the tool to make the holes. They run about $50 a day to rent.


    Back in '91 I did a second story addition in San Jose California and we had to epoxy the bolts into the foundation, as well as other major structural support. It would be a good idea to check with the building department on whether epoxy will be required or not.

  3. #3
    Join Date
    Jan 2008
    Location
    Lakeland ,MN
    Posts
    356

    Default Re: Earthquake-Proofing Anchor Tips - Concrete Drilling & Nailguns

    A Spruce Good call on the palm nailer. I might suggest ussing a high quality hammer drill like Hilti with hilti drill bits. I have used these hammer drills over the years and never came across anything they would not penetrate using the correct bit. They are very exspensive but are the best on the market in my opinion.

  4. #4
    Join Date
    Aug 2007
    Posts
    6,481

    Default Re: Earthquake-Proofing Anchor Tips - Concrete Drilling & Nailguns

    I agree, Hilti's are top of the line and very expensive. Most rental yards have Bosch and I've used an Hitachi with good success. If money were no object though, I'd buy Hilti.

  5. #5
    Join Date
    Feb 2008
    Posts
    43

    Default Re: Earthquake-Proofing Anchor Tips - Concrete Drilling & Nailguns

    outstanding advise - thank you mr spruce! you even threw in pictures for extra bonus points. they should feature you on an "ask this old house" episode!

    i rented a 15lb hilti rotohammer from hertz just a few days ago with a chipping bit to bust out some concrete left over from cutting windows. now i understand what the drill vs. chisel mode was all about

    i have a plan! thanks again.
    -brett

  6. #6
    Join Date
    Aug 2007
    Posts
    6,481

    Default Re: Earthquake-Proofing Anchor Tips - Concrete Drilling & Nailguns

    Quote Originally Posted by brettmarl View Post
    outstanding advise - thank you mr spruce! you even threw in pictures for extra bonus points. they should feature you on an "ask this old house" episode!
    You're welcome. Pictures of tools are easier to convey what it is we're talking about than mere description. As for being featured on ATOH, have your people call my people.

    Quote Originally Posted by brettmarl View Post
    i rented a 15lb hilti rotohammer from hertz just a few days ago with a chipping bit to bust out some concrete left over from cutting windows. now i understand what the drill vs. chisel mode was all about
    Just so we're clear here, you'll be installing a masonry drill bit in that rotohammer to drill holes for your anchors. Rotohammers also accept chisels and points for breaking things up, which is different from drilling pretty holes in your foundation.

    Think of it in terms of the right sized tool for the job. For drilling holes in concrete you need a tool that can dole out a serious whack as it turns the drill bit, that's a rotohammer, not a drill. There's also the whole Tim Taylor thing too, which is never a bad idea (Arrr, Arrr, Arrr more power!!! )

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