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myles's picture

Tapcons (post #89121)

What size Tapcons should I use to fasten sleepers to concrete slab as basis for subfloor in basement- 3/16" or 1/4"? How far should they be spaced? I intend to lay some construction adhesive down also.

(post #89121, reply #1 of 10)


I have used a lot of tapcons, when I am deciding what size to use I take into account the material as well as what I am fastening. Here are some things I consider.

The 3/16 can have a tendency to break off if you tighten them with a drill, and they catch. However when drilling into conc. block sometimes you hit a void and the tapcon wont tighten up. If you start with the 1/4 you have no other option. If you drill first for the 3/16, and it does'nt catch than you can go to the 1/4.

This is'nt a big deal but it happens from time to time (mostly with block).

You should be fine in concrete with either one for sleepers. I would probably go with the 1/4, especially if you can't wait for the adhesive to dry.

I think I would space them about every 16 inches. Also remember to drill 1/4 to 5/16 deeper than the anchor you are going to use. This gives the dust somewhere to go. This is extremely important in a vertical (down drill operation). If you don't the anchor won't tighten properly. If you don't have a hammerdrill rent one it will save you time and bits vs. a rotary only drill.


(post #89121, reply #2 of 10)

Hey myles,

It is me again. Also extremely important that you use the right bit. 5/64 masonry bit for the 3/16 anchor. 3/16 masonry bit for the 1/4 inch anchor.


(post #89121, reply #3 of 10)

Read the package. It tells you on there what size to use per thickness of material.

(post #89121, reply #4 of 10)

I'm cheap. Tapcons aren't. Wouldn't a concrete nail or expanding anchor be cheaper and sufficient for subfloor sleepers?

Just asking.

(post #89121, reply #5 of 10)

Hi stray,

Concrete nails pain in the a**.

Expanding anchors okay, but you still neeed to predrill.


(post #89121, reply #6 of 10)

If the concrete is older (harder) you will want to use 1/4". The thinner ones will break more often in harder concrete.

Also use the right length trying to sink them to deep will only break them and ruin your driver, or wrist, or both.

1-1/4" into the crete no more and no less than 1" or you will not have sufficient holding power.

Mr. T. (Tapcon)

(post #89121, reply #7 of 10)

Like I said in an earlier post the 2 3/4" hex head work the best when attaching 2x material.

(post #89121, reply #8 of 10)

I agree on the hex head, That's about all I use. Counterbore the sleepers to sink the hex heads.


(post #89121, reply #9 of 10)

What about shooting pins (power acuated fastners)? Every job I have seen, the wood floor guy shoots his sleepers. Differnet loads for different density of materails.
What kind of floor?

(post #89121, reply #10 of 10)

I agree with RD, PAF's are the way to go because they're fast, and you can always shoot more in if some don't take. They only other way I have set sleepers, plates, etc. is with split-drives, usually 1/4", with a success rate of about 95%.