Holding garage to floor?

I moved my 2 car garage to a new slab of concrete, how do I hold it down? My old floor had 3/8 studs in the concrete. Can I use 3/8 self tapping concrete screws with a hammer drill and just screw them in? I have 2 2 by 4 sill plates stacked on top each other so 4" or 5" screws?
 
(quoted from post at 22:53:15 04/13/15) I moved my 2 car garage to a new slab of concrete, how do I hold it down? My old floor had 3/8 studs in the concrete. Can I use 3/8 self tapping concrete screws with a hammer drill and just screw them in? I have 2 2 by 4 sill plates stacked on top each other so 4" or 5" screws?
se the 3/8 studs that you planned ahead & put in your new slab. :)
Seriously, there are many good, strong expanding type concrete anchor screws on the market. Not keen on self tap. Definitely not keen on epoxy like the supports for the suspended concret ceiling slabs used in the deadly "Big Dig" tunnel in Boston! :(
 
You want to ask / findout if the manufacturer of whatever device is, has had it approved by a third-party inspection agency, to substitute for actual 1/2" J-bolt anchor bolts. If so, they will know exactly what you are talking about. You will be able to get a copy of the NES [National Evaluation Services] approval report. In the approval section of the document, you will find the conditions of use, what it is approved for.
One of the best manufacturers of such devices is Simpson, but i dunno if they make such a bolt.
If not, or if you get a blank stare, or if you get 'promoted', I'd keep looking. Your local building inspector is in the job of helping you find such information, go ask. That's what they're there for.
I've never NEVER had an epoxy - held bolt actually hold. I've always pulled them right out.
 
I would put the anchor bolts in the wet concrete. Put down a new treated plate then
attach old garage to new plate.
 
No offense but you should've thought of this BEFORE you poured the concrete and moved the garage! A sudden wind storm will have your garage rolling across your yard.

I would use drive-in anchors at this point. Since you can't lift the garage out of the way to install them properly, you can drill a bigger hole through the sill plate, then drill the anchor hole in the concrete, drive in the anchor, and use a large washer or steel plate on the lag to anchor it down.

Large Tapcons might work, but I'm not sure if I'd trust them over the time-honored method above.
 
Hilti worked out great for me. Concrete contractor failed to install bolts. We hammer drilled into slab, cleaned out dust with compressed air, and set anchor rod in 2 part Hilti epoxy. Building inspector was happy, and earthquake in 2011 didn't move any walls
 
We used epoxy on hangers at the George Washinton Bridge for 5/8 stainless rod. 30 seconds after banging in the rod you could do pull-ups on that rod. If your epoxy failed you left too much slurry in the holes. Epoxy is specified as the whole bridge vibrates.
 
I would agree with dr sportster, Hilti 2 part epoxy anchors will provide strong pull values, besides shear. The drilled hole must be cleaned properly before the anchor is set with the injected epoxy. Unless the substrate (concrete) is defective, the edge distance to shallow or not coordinated with other components, this type of fastener will certainly perform. With a problem like that, the manufacturer's representative would be called in and a pull test requested. I've been involved with many of those tests in actual field conditions, even off swing stage scaffold way up on the exterior of buildings.
 
Thats just a missed coordination and or detail, happens, but this one is kind of obvious, should have been done prior, but.... LOL !

You can look at fastener manufacturers information and obtain pull out and shear values of fasteners that are installed into concrete. Mind you the concrete design mix needs to be known, 3000, 4000 psi etc. To prove it, technically speaking you would still have to do a pull test, but if your concrete is good, it should be no issue.

For ease of installation, I would suggest a mechanical fastener, Hilti sleeve or wedge anchor, or the current equivalent. Red Head,(which I used exclusively on one 15 story building) and others like Powers or similar should have mechanical fasteners for concrete. Powers used to offer a fastener with a certain thread designed to perform like a thick tapcon, so its possible you may be able to do that. I recall when these were new, I was hesitant to use them on commercial buildings, having worked with wedge, sleeve and epoxy anchors/fasteners, they were new at the time and I questioned thread engagement, given concrete, steel reinforcing, aggregate etc. Powers had a failure in one of the tunnels in Boston, Mass., don't recall the details or what fastener, thought it was the epoxy type. Specific to that job more than likely.

With a mechanical fastener as mentioned above, drill the correct diameter through the sill plates, drill a larger hole to recess a washer and nut if you like, just partially into the top plate of the multiple sill plate. Get a hammer drill, match the bit size to a 3/8" or 1/2", (probably best) sleeve or wedge type anchor, mark the bit for correct depth, so you know where to stop, allow for the bottom sill plate thickness. Drill the holes, clean with compressed air, drop and tap the fastener into the hole, then install the nut, washer and tighten it down, the wedge or sleeve will expand as the end of the fastener is tapered or is designed to expand when tightened, don't over tighten, there is likely a torque value if you want to get fancy.

Details of the concrete are important. You are on the edge of slab with the wall, so edge distance with mechanical fasteners is important, you need a certain amount of concrete both depth and what surrounds the fastener, and the manufacturer should provide the acceptable tolerances for each fastener. You don't want to violate that specification, the fastener will either fail or the concrete will spall, fracture when you tighten it, causing failure. 1/2" fasteners will need more edge distance, 3/8" may need less, so if 1/2" does not coordinate with the slab detail, see if 3/8" will. You may be able to get the same overall values, pull, shear and whats transferred from wind loading, using smaller fasteners, but more of them. Just make sure the spacing allows the correct edge distance. Epoxy anchors are often used when edge distances won't allow a mechanical fastener, also for many other reasons, like Dr Sportster said about the G.W.B. where they were used and it seems for dampening purposes given vibration.

If there is reinforcing in the slab, probably no bigger than #4 deformed bar, or much smaller 6"x6" woven wire mesh, its best to avoid steel with masonry drill bits. So if you have any idea that if the edge of slab is tapered on the bottom, like an Alaskan slab, thicker on the perimeter, there could be a pair of deformed bars all the way around. We can't always predict where we will find rebar in concrete on high rise jobs, but do try to avoid it as much as possible, wears bits quickly, even Hilti ones which are good quality. I would look at structural details and approved shop drawings to locate reinforcing, then detail the structural connections for our work, often times submitting details based on field conditions after doing a mock up of an installation, even if just with fasteners, it saved me lots of headaches, and one job I redesigned the connections because it was grossly mis coordinated per the design, we could hardly get a fastener in the original location. Well thats for big jobs, but the priniciple applies. A little careful planning and layout goes a long way no matter what you build.

As a general rule of thumb with mechanical fasteners into concrete, concrete block or C.M.U., it should be coordinated in advance with that work, makes the job so much easier and the fasteners will perform. I did some repairs to a fancy stable in Wellington Fla, years ago, all of the stall gate hardware was mechanically fastened into CMU walls, problem was they left the cells hollow, and the fasteners were failing in the thin wall CMU. At some point that hardware should have been located, marked on a drawing and it made so when the CMU went up, filling those cells to provide adequate structure and depth for these kinds of fasteners. Just an example that would have made a big difference if someone had taken the time to coordinate these details, the remedial work is much more costly.

Click below, I did a search on Hilti epoxy and sleeve anchors, lots of photos and product data, you could refine your search for sleeve anchors if you like, you'll see charts for values and typical details.

Many if not most fasteners like you get at HD or Lowes, will not provide any values, like deck screws, for example, have no shear value at all. One needs to use care when selecting fasteners for any structural component.
Hilti
 
The 1/2" Red Heads should be fine for most home owner / farm fixes...still need a good hammer drill bit(s) and hope you don't hit metal.

The Hilti epoxy anchors are great, but unless you are a contractor, you may not even be able to buy them. One of our guys had to take a "lesson" from the Hilti rep to ensure the product was being used correctly. They are excellent...however we have fastened some pretty big stuff with the Red Heads and they are still attached...even with the odd loader tractor driving into the bunker walls.

Good Luck, Grant
 
Wow! Been building stuff for 28 years! Bridges, box culverts, high rise, houses, CMU, steel, precast.... Never got this much
technical data from a SER of a project!

First look around at 120 year old buildings before exopies, resins, and post install mechanical anchors. The old timers had it
figured out! The Romans didn't use epoxy! The Egyptians had no stainless anchors! Use some 1/2" Red Heads with
embedment at least half depth of the slab.

It's sounds like a pretty standard garage, not the Taj Mahal. Would have done the same myself.
 
use what I call red heads. You drill into the concrete thru the base plate and put expanding bolts into the hole and tighten up. Quick and easy Just mahe sure you clear the hole by blowing thru a piese of small tubing or a straw to clear out the debris in the hole. easy as pie.
 

I know what I would do but then I don't live in " Tornado Alley" I would check to see if I could find out what code says for my area, then go 10% more.
 
The deeper the better. From what I read, it sounds like you are asking if you can use tapcons. I have and do use tapcons plenty, even for anchoring walls to basement floors so that they don't move, but I also take the walls all the way up to the floor joists so that the tapcons hold the walls from moving horizontally. I use tapcons a lot, but I wouldn't for the application that you're asking about. As many others have suggested, use redheads, and best to take them down half the thickness of the pad. Depending on the bag mix, you might be in for a workout drilling them. Best of all is to drive them into wet concrete of a new pad, but that kind of luck is rare. You might be in for a drilling workout.

Good luck.

Mark
Use these
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top