I am currently busy converting a former tortilla factory into a church. I work in Southern California, so that statement isn’t as random as it seems. The building is a 22 year old tilt up and about 30,000 square feet in size. The original plans called for the concrete floor to be installed at 6,000 psi. After all these years we estimate that the floor is now about one trillion psi. We have had no luck using our powder actuated tools to anchor our mudsill to the floor. I have a Hilti dx36, 451, and 460. Even using Hilti’s heaviest black strip loads, I am having no luck. So far we have drilled and installed over 500 3/8” wedge anchors, but would like to avoid that as we advance. Some of you old dinosaurs may remember the fun we used to have with the Ramset Jobmasters, and I am wondering if there is anything comparable out there. Advice?
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Replies
Call your Hilti rep. You'd be surprised.
Well, you can tell by the way I use my walk, I'm a woman's man, no time to talk. .
http://www.youtube.com/watch?v=Dy3LM5_-i1Q&feature=related
I agree with Gunner, call your Hilti rep.
It's hard for me to believe that your DX451 can't penetrate. We use that same model and never had a problem. A lot of the concrete foundations we shoot into are waaay older than 22 years. Heck, we even fire into steel columns using that model...something aint right.
Davo
if the floor is clean & smooth... 3m makes a double sided tape that will bond it to the floor where a forklift can't pull it up.... 3m VHB (very high bonding) it'd been used to bond aircraft skin... i often use a 3/16 hammer drill and 2 sinkers ...cheapest way out but takes time... also have used liquid nails and only a few fastners..
p
I appreciate the responses guys, but I talked it over with my Hilti rep before posting here. I always go the the manufacturer first. They just couldn't help me with this one. We want to be able to shoot a 2-7/8 pin with attached washer into this concrete. All of my current guns will easily shoot into standard steel columns, so this one has me baffled. Thanks again.
PL Premium will weld those plates tot he floor overnight.
if the surface is glassy smooth with old coatings, a grinder to etch it first.
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Taunton University of Knowledge FHB Campus at Breaktime.
where ...
Excellence is its own reward!
if the floor is clean & smooth... 3m makes a double sided tape that will bond it to the floor where a forklift can't pull it up.... 3m VHB (very high bonding) it'd been used to bond aircraft skin... i often use a 3/16 hammer drill and 2 sinkers ...cheapest way out but takes time... also have used liquid nails and only a few fastners..
PL Premium will weld those plates tot he floor overnight.
Both those ideas, while seemingly sound, are not worth trying on a commercial job in a siesmic area. The inspector will want a connection method either per plan, or as an ICBO assembly. Not even worth trying, unless you are want to demostrate to the inspector that you are a total wing-nut
What do you suggest then?
What do you suggest then?
Either wedge anchors, or a talk with the engineer. I am assuming that these must be bearing walls, supporting either a second floor or a mezzanine. If they were partition walls only, I am sure that metal studs would be the preferred construction medium, and shots thru the bottom track would be a piece of cake.
But regardless, I did make a suggestion: don't do anything dumb
I think the original poster was having problems with shot not working in the concrete and was looking for suggestions.
Point taken. I have never worked under seismic concerns and standards, so my ignorance on that is showing.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
We had trouble with firing Hilti nails into concrete cielings. We were just blowing out craters around the nails.
Our hilti rep had us drill a short pilot hole before we fired the nail in. It worked.
The concrete was just to hard and brittle.
Do you mean a pilot hole just through the wood? If so that's the route I would take. Makes sense, give all the velocity to the concrete and easy to predrill the plates. Mike
Trust in God, but row away from the rocks.
We were attaching 16 gauge metal track when we did it. We would drill through the metal and about 1/2" into the concrete. It went pretty quick with a roto hammer.
Our problem wasn't getting the nails in as much as blowing craters where we fired the nail in.
But I think drilling a pilot hole in the concrete would work the same for a lot of problem areas.
I can't remember if the pilot hole was a smaller dia than the nail but it would make sense to have it smaller than the nail dia and shorter so at the end of the nails insertion it is into concrete without a pilot hole. Just start it out in one.
I'm with Piffin: PL Premium--but I'd run in some Tapcons to hold them in position while the glue dries.
Either that, or borrow a bazooka.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
True, but5 that cuts the number of holes drilled to about 15-20%I will also weight down with bags of mortar mix or whatever is handy overnight.This is a large commercial job, so it might not be as efficient to use PL as on a small residence though. Lot of guys doing a lot of different things means a lot of plates getting knocked out of place before the glue kicks. Gotta control that somehow.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
If you are doing a lot of them. Why not use the 3M tape or hot melt to hold them in place until the PL sets?.
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
PT likes to start warping and twisting pretty quick once it is unbanded sometimes.I have only just now learned about the 3Mtape. Sounds pretty good.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
That high bond tape is also what is used to attach trim molding to cars. .
.
A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Lot of guys doing a lot of different things means a lot of plates getting knocked out of place before the glue kicks. Gotta control that somehow.
That's what the bazooka is for....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Hi framerboy,
I spoke with my local Hilti rep today about your problem. He said to drill a 1/8 pilot hole and then fire your round. The way he was talking, you drill the pilot hole thru both the sill plate and the concrete floor before firing, so to me this is still too time consuming...if you are gonna drill, might as well still go with the wedge bolts, right?
My rep said Hilti has a new nail...it has a twist (thread) built into the bottom portion. It's called X-U Premium. My rep says that nail should work nomatter what.
My rep also said your concrete may have crushed granite aggregate in the mix; which is causing your "hard" problems....he said he has come across this a few times and trouble with nails are common.
Hope this helps.
Davo
Okay you all, thanks for the replies. The adhesive solutions are out, the connections must be mechanical in nature and Sunny SoCal is most definitely a seismic wonderland. Davo is right about the pre-drill, my rep suggested it also, but we have the roto hammers out anyway may as well go with the wedge anchors. I am aware of those new pins, but to my knowledge they do not come with a pre-mounted washer. I will try them out anyway to see how they do. I would like to avoid the wedge anchor circus the next time this happens. Breaktime is a great place to go when you need a construction question answered or want some advice. Thanks again.