hey guys,

as some know, I installed a dricore subfloor. After installation, there are a couple spots where the sub floor tile is not in contact with the cement. As a result, the floor flexes. This makes a noise, and the 'flex' carries across the floor.

I want to fix it, and need some input. I have tried tapcon screws of various sizes, however the heads shear off before screwing in far enough to anchor the floor panel securly.

I am thinking a hilti type nail gun might work, but since the floor is OSB and not pywood, I knda think the nail will shoot right through the floor (ie not enough resistance in the OSB compared to concrete.

My other idea was to install a second subfloor over top of the dricore using 4x8 plywood (thickness?), but I am not sure if that will get rid of the problem, plus it is a bit more work at roughly 25 sheets needing to be cut.

What do you guys think?

 

The tapcons shouldn't shear off if you are drilling the hole for them deep enough. You are using the concrete bit that comes with the screws?

 

yep, I am definitely using the right size (depth & diameter) bit for the tapcons.

I used hex-headed one on the partition walls; they went in with the aid of a ratchet, but I can't countersink them for a floor application.

 

did you use the little rubber spacers that come with the dricore to fill the shallow spots? that should go a long way towards solving your problem.

odd the issue youre having with tapcons. they're usually pretty easy to use in concrete slabs.

 

There was only one low spot where I felt I had to use the spacer, the floor seemed to be going down quite level, and it wasn't until after the whole floor was down for a day, that we started noticing the flex.

I took out the 1/4" wall spacers hoping that would help it, but its not a case of the floor being too tight; it's an uneven concrete that I didn't notice. It's probably too late now to go back and fix it with the dricore shims..unless I saw out the panels?

Yeah, the tapcons are giving me a lot of grief. I am using a hammer drill and going through a bit every 3-4 holes. I wonder if I should be wetting the bit?

 

The bits suck. I used a passload to secure the bottom plates in my basement. But that won't work in your application, you're right about it driving right through the plywood.

What size screws are you using? Are you using the appropriate size bit?

Are you using the hammer drill to install the scews? That could be an issue. I used the hammer drill to make the holes but a standard drill to install the screws.

 

That was going to be my question.

 

Ya, the bit won't make it past 4 holes. That's not unusual. The bits do suck. But drilling concrete is rough business. Even the best bits won't last long.

Like the others said, make sure you turn off the hammer function (or, better, use a different drill) when installing the screws.

If all else fails, drill deeper. The only other explanation is you're just not drilling deep enough. The tapcons can't self drill.

 

Yep, using my regular makita to drive the screws and the hammer strictly for the hole itself. Neither drill is giving me enough torque to set the screw all the way in. For the studwalls, I had to use a ratchet and 10mm bit to get enough leverage (i would guess 100 ft lbs at least)

The holes are def deep enough, I have tape marked on the bit. The screws get about 2/3 of the way in and then become very difficult to turn. I have got the odd one in, but then I turn it too far, and it 'strips' before pulling down on the floor.

NSX - thanks for the info on the nail gun, that's what I figured.

 

have you tried a 10mm bit on your drill? that's what i normally use for tapcons.

 

yep, the 10mm hex head tapcons are going in OK. The prob is with the pan head screws that take a phillips bit. I need to use a screw I can countersink flush into the floor. Hmm - you got me thinking though - I wonder if I used a small forstner bit to bore out a recess for a hex head?

 

Do you have an impact driver. I found that using an impact driver works a lot better than a drill driver. It certainly gets around the torque issue.

 

You can't use a washer with one of those Remington nail guns?

Mike

 

no, but now I have an excuse to go buy an impact driver. Wonder if Princess Auto has any on sale this week ;-)

 

Princess Auto hasnt published their new flyer yet for this month... Already 3 days late.

Canadian Tire doesnt have any on sale this week... Maybe this weekend with the new sale flyer.