Laying 3/4″ plywood furring strips on a concrete slab for a radiant heat floor. May need to need move these strips before finished. Using tapcon screws (blue cement screws from ITW) to fix strips to slab. Since screw heads must be flush with top of strip, using Phillips head screws and countersinking top. Chewing up Phillips bits and stripping top of screws. Having one difficult time driving the tapcons into the slab. Any suggestions to make the job easier?
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v,
Make sure you are drilling the pilot holes deeper than the depthe of your screws. These screws make chips as they are driven and if the holes aren't deep enough they bottom out before they can countersink themselves. This is due to the buildup of chips in the bottom of the hole with no where to go. Concrete is an unforgiving material in this situation. Also make sure you are using the correct size bit to drive them.
Mark
Using 3/16 X 1 3/4 screws. Drilling holes at least 2" deep. Using #2 Phillips bit to drive tapcon screws using ratchet. I think my problem is that I have never encountered concrete this hard before.
I do not have any real problem with 3/16 X 1 1/4 tapcon screws. But these have only 1/2" in the concrete.
You might check and see if they will take a #3 bit.
I don't remember the brand, but Lowes has both the Tapcon's and another brand. The other brand will take a #3 bit and in fact comes with a bit in the pack of 25.
I see where you say you are using a ratchet: is this, by chance, a square-drive ratchet like the kind you'd use for sockets ? If yes, then you may find that you have insufficient down-pressure and that's why the bit is stripping the screw-head. If I'm right so far, do you have a "speed" handle in you socket set ? It's the one that looks like a brace, and they're super for hand-driving screws..
Phill Giles
The Unionville Woodwright
Unionville, Ontario
I use a SDS drill with the appropriate size bit, make sure that you drill the hole deep enough. Remember that the hole has dust in the bottom so drill it deep. I have also found that you can use the 1/4' hex drive head, the head will sink into the wood.
I used to use blue Tapcons like you're talking about, but had the same problems over and over again.
I now use split shank fasteners. There are a couple of different types, but in general they look like a large nail with some sort of bend in the shank. All you have to do is rotohammer a hole (1/4" is typical for the size I use) and then pound them in. They work incredibly well, and I've yet to have a problem with a single one.
Ragnar
The bent-nail fasteners work very well, but in the original message he said that he may need to move the furring strips, which means removing the fasteners...those bent nails don't come out easily.
Two thoughts on the original question: vacuum the holes to remove excess debris before inserting screws; try using a cordless impact driver (do a search of this site for relevant discussions).
Elcid,
Sorry - I missed his comment about possibly removing the sleepers.
However, I've had extreme problems in getting the blue screws out, too! And screw shanks are so tough, it was nearly impossible to get them out once jammed. I don't know the exact probability of him having to remove the sleepers, but unless removal is likely, I'd still recommend the split shanks.
If using the screws is unavoidable, I'd look into using an impact driver, like you suggested. I think that the sockets on impact drivers have a higher surface hardness, and may stand up better to the screws. When using standard grade six-point sockets, I kept wearing them out.
Ragnar
Edited 12/30/2002 12:34:23 PM ET by ragnar
Vheying,
The split shank fasteners I mentioned will really make your life easier! However, as Elcid pointed out, you said you might need to remove the sleepers. Is there any way you could avoid this possibility?
Ragnar
The solution to my need to remove the sleepers is to hire someone who knows what they are doing.
I would hire some one if I could figure out who they might be. I am located in central michigan 50-60 miles from anywhere.
The room I am putting the radiant floor in is roughly triangular with 2 outside walls. Using panels would leave too many empty places. So I am building a custom floor. since neither I nor my heating contractor has ever worked with PEX tubing before, it is a learning experience for both of us.
At least my education here only costs me time, patience, and some sore hands.
Thanks to all who responded. If nothing else, misery loves company.
Tapcons work by gouging out threads in the concrete. With average hardness concrete, and even more so with mortar, the screw cuts the threads and holds well as long as there is space for the cuttings to go. That extra half inch or so is important.
But that is not where, IMHO, the problem lies. As the hardness of the material increases the harder the screw must be pushed to cut. I think that the holes are too small. A worn bit will tend to cut undersized holes. In mortar the material would be so soft that you wouldn't notice but with very hard concrete you are facing frustration. Get new bits made by the same company and replace them as soon as the screws start getting tight again.
You might get just a little more wear from a bit buy wallowing the hole slightly. This also give you a clue as to the cause of the problem. If you, using the same old bit, can ream the hole and wallow it out and then the fasteners sink and hold well you have identified the problem. Don't forget to make the hole deep enough and just a bit more. You should get spare bits as they will wear quickly in hard concrete.
In vary hard concrete, 60+ years old where a new bit won't get it, a bit 1/64" oversized may be warranted in non-critical applications. Sleepers on a floor are under little tension so I think this would qualify but only if absolutely necessary. In critical applications I would consult with the manufacturers technical assistance department or engineers.
I've found a 4# hand sledge works well to set tapcons in the last 1/4 inch: never accurately measured the difference in holding strength, but none that I've driven in have ever fallen out in horizontal bookcase or cabinet installations I've done.
Use a hammer drill that uses the splined shank type bits. They drill into old concrete like butter The 50 bucks you might save on a cheap hammer drill is not worth it. Bosch and Hilti make decent splined bit drills.
Using a Bosch hammer drill. Is there a special model for spline bits? Or are these just special bits?
By the bye, what is an SDS hammer drill? See, I should have hired someone who knows what they are doing.
"SDS" describes the bit locking system of the drill. Looks like this:
View Image
Mongo,
I've only ever used SDS tools. What's the alternative -- just some sort of smooth shank like a regular drill bit?
Ragnar
There is spline drive, whch has grooves/splines along the length of the part of the bit that gets chucked. Round hex. SDS, as well as SDS-Max.
SDS wins the award.
The splined bit drills start at about $200. Bosch makes a cheaper hammer drill that fits he garden variety concrete bit. I don't reccommend it. I don't know what SDS is. SDS to me is the Simpson screws that my engineer loves so much but they are specced for wood, not concrete. Must be an east coast epithet. A vac for cleaning the holes is inadequate. Attach a section of plastic tubing to your compressed air blower and blow out the hole. Do not use the hammer function on your drill when driving the screw. I have done millions of screws into concrete.
There is some bad advice on this thread from rank amateurs.We may be slow, But we're expensive.
Using a Bosch hammer drill with a chuck tightened with a chuck wrench. However, my problem is not drilling the holes, it is rather setting the tapcon screws.
Over the New Year's holiday I will be trying some of the suggestions for setting the screws. Have already tried driving the screws with the hammer drill. The drill chews up the bit/screw combination in less than no time at all.
Two things suggested seem to help so far. One is to make certain the hole is deep enough and clear. Checking the hole with a small Phillips crew driver to insure the hole is deep enough and clear. The second is to rap the screw with a hammer when it becomes almost impossible to drive.
My shop vac is not worth anything for clearing the hole. Best success so far is to insert the drill several times to remove the waste. No compressor, but I may buy some of the compressed air cans sold for cleaning computer keyboards.
Can find only one place to buy 5/32 masonry bits. Only known next size larger is 3/16, which is too large for the tapcons I am using.
I appreciate all the comments. If nothing else it is nice to know that I am not the only one with this problem. And that there are simple answers.
Relton makes 11/64 masonry bits. I haven't done business with this vendor, they're just the first one that Google coughed up.
http://www.mytoolstore.com/relton/ramtip.html
Google is your friend. :)
Edit to add: The search string I used was
"11 64" masonry bit
Edited 12/31/2002 11:48:52 PM ET by Uncle Dunc
Well, I'll take the bait on this one. There is some bad advice on this thread from rank amateurs. Yeah, and in this case part of that applies to you. I don't know what SDS is. SDS to me is the Simpson screws I find it hard to believe that you have installed millions of screws, which means that you have been in the trade for quite a while, and you think SDS is a Simpson product. What's the old cliche...there's more than one way to skin a cat...different procedures work well for different tradesmen. I personally have good luck vac'ing a hole, and find that the compressed air is a hazard and a nuisance. I respect your methods, as they seem to work for you. Please don't insult me and my techniques. The purpose of this forum is to exchange ideas, not to belittle others. Now, if someone gave truly bad advice, such as using lamp cord for lighting circuits, it would be appropriate to point out the error.
My sentiments exactly!
SDS has been around awhile, works well (and that's the only kind my current hammer drill accepts) and I'm even a West Coaster and, while I've not planted MILLIONS of screws and bolts and anchors of various sorts in concrete, I've planted a good share and a good variety.
And Yea, I've used the spined bits and core drills and I've set a lot of heavy machinery in a past life using a lot of different methods, but the original poster is just trying to sink some Tapcons to anchor some furring strips and gets only ONE self-proclaimed source of proper advice! Sheesh!
And to that original poster, I think you misunderstood some posts: A hammer drill is for drilling the holes; a small impact driver, like a Makita 12Volt cordless works well for driving the screws. And that is not bad advice; it's good advice personally experienced by me (who never shops for SDS bits in the Simpson display).
HAPPY NEW YEAR!!!Jules Quaver for President 2004
I appreciate the patience and courtesy all you folks have extended me.
This is almost a real time report. This morning I am using 2 suggestions. I am making certain the holes are deep enough and are clean. When the tapcon is about to stop driving, I hit the top a few times with a hammer. This seems to free up the tapcon, which I am then able to drive a few turns further. Then bang it a few more time, and turn it a few more times.
This may be slow, but it is a lot faster than waiting a week for delivery of an impact driver and slightly larger masonry drill. As I said earlier, it just takes time, patience and sore hands.
I would never do a commercial job this way. But its inexpensive. The extended familiy arrives at the end of the month for a ski weekend. Must have the room ready by then. The sleepers are jsut the first step. Then there is laying the PEX tubing, running the lines to the boiler, filling the space around the tubing with cement, laying a subfloor, etc.
Laying the subfloor will be a real experience. Must lay and fasten the subfloor before installing the PEX tubing. Otherwise, I will have the joy of repairing all that tubing I puncture when I fasten down the subfloor. So install the subfloor and then remove it to lay the tubing. Cement the tubing in and relay the subfloor.
Any suggestons on how I can quickly change this basically triangular, actually pentagonal, room into a rectangular room. If I had thought of this first, I would have saved myself considerable work.
Back to my banging and screwing. You folks may hear more from me.
Another thing which works for me and I think hasn't been mentioned yet is to, when you feel the screw getting harder to turn, stop and back it off a turn or so, then continue forward. I think this lets the cement dust fall out of the already-cut threads before you continue. The already mentioned comments about using the proper size phillips head driver are also good - I think a number 3 or possibly 4 work much better than a number 2 - the bit should be very snug in the slot.
Hope this helps. Rich.
I had noticed that if I replaced the tapcon with another tapcon, even a used one, things seemed to go much better. Just a variation on your 'back the screw off' technique.
Thanks.
Anyway, I am banging and screwing like mad this afternoon.
Too late for you now, but next time (?) order square drive (Robertson) tapcons from McFeelys, or drive across the border to a Home Depot in Windsor:
http://store.yahoo.com/squaredrive/fasteners-screws-concrete-screws-steel-w-epoxy.html
I've only ever used a 5/32 inch drill bit for 3/16 inch square drive tapcons. The biggest problem I have using square drive is snapping the screw in two, not stripping a crappy Philips head. I feel sorry for you Americans... ;-)
If you back the screw out, you might also vacuum the hole again.
Regards,
Tim
OK OK I thought the use of a cordless drill for setting screws in concrete was bad advice. Maybe that works OK but compared to a real power drill, any cordless is gutless. When you have a lot of screws to set in concrete then you can save a lot of time by running a cord to the pole. Also the use of a vac requires the hole to be vented. The dust may be cleaned around the hole but not in it.
Look in the Simpson catalog for SDS. They are talking screws.We may be slow, But we're expensive.
But check the Bosch catalog for SDS drills
http://www.boschtools.com/Tools+and+Accessories/Tools/product_list.htm?link=product&hierarchy_id=59141
.
Phill Giles
The Unionville Woodwright
Unionville, Ontario
Edited 1/1/2003 11:33:30 AM ET by Phill Giles
but compared to a real power drill, any cordless is gutless. You're exactly right. However, we're talking about a cordless impact driver, which is designed for the sole purpose of driving fasteners, and it works very well.
I used to have frustration with tapcons, but a cordless impact driver solved the problem. I've always used an SDS hammer drill (Milwaukie in my case) to drill and always drilled extra depth and vacuumed out the holes, but the SOB's were a booger to drive.
12V. Makita hammer drill and Voila! Hex head, phillips, doesn't matter. Just set about 200 lin ft of sleepers and hung conduit hangers last week...snapped one bit...big deal.
Jules Quaver for President 2004
Using a Bosch hammer drill. Don't know if it is SDS. Always vacuum out the holes to the best of my abilty (small deep hole is tough to vacuum).
I will try using the hammer drill to set the tapcons.
Small holes are actually very easy to vacuum. Just place the end of the vac hose over the hole, with the entire rim of the hose touching the concrete, and it just takes a second to suck everything loose out of the hole.
I work with tapcons often. Most of the advice has been good, but let me throw in my two cents. You definitly want your hole deeper then the screw. Clearing the hole with a vacume doesn't always work because of the small size of the hole. You may find a blast of compressed air works better. (can you say eye and nose protection) Another thing I've found to help is an "oversized" hole. I use a 7/32" masonry bit in a sds hammer drill. I've never seen or heard of a 13/64" so it's the next size up from 3/16" that I'm able to find. In very hard concrete this makes the screws go in without a fight, but they still bite or grab well. When I do this I try to put at least 3/4" of screw into the concrete. This usually does the trick, good luck... BUIC
An 1865 two and a half story brick building that I own (or vice versa) has taught me some things in the last seven years. Tapcons don't work too very well in this 1865 soft brick, so I add a sliver or a toothpick or a strip of #14 guage copper wire etc., having drilled the standard diameter hole.
Now with concrete I'll pick up my 1/4 inch SDS and shoot in a hole and then use a sliver of wood or #14 wire or strips of tar paper in the hole and then jam in a 2-4" drywall screw, coated if the application risks corrosion. I find the Tapcon too exacting and my method more forgiving and flexible. Tapcons aren't cheap either.
In soft mortar you might try going 1/64" smaller on the drill size. On very soft mortar I have had luck going 1/32" smaller. I haven't checked with the manufacturers on this and feel I should if I was hanging a load in tension on these. As long it seems to hold well and the loads are light and in shear I don't worry too much about it.
SDS+, SDS Max, and Spline Drive all refer to variations of the drill bit shanks and matching chucks- as opposed to a standard straight cylindrical shaft. All are vastly superior to a plain shank, especially if you have a lot of holes to drill- they keep the bit from walking out of the chuck, or loosening the chuck, under impact and vibration. Bits are more expensive but you can get adapter chucks- at least for the SDS+ size- so you can use regular bits, too.
a quick trip to lowes or hd will show you the differences.
m
A quick trip from here is 46 miles one way and 60 the other.
Only have one more small project for which I need to drill masonry.
Probably going to sell that hammer drill pretty quick.
hmmmm... i thought maybe there would be some good pictures and descriptions on the boschtools.com site but i just checked and it's not much help either. not sure where you could learn about these things on the web- bosch makes drills and bits for all four types so i thought that would be the place to go. i did notice one thing on their site- they refer to units that have a standard chuck for regular type bits as "hammer drills" while any unit that uses one of the other three shank/chuck systems is categorized as a "rotary hammer". sorry.
m
Being a commercial roofer I have used and installed thousands of the tapcons always had problems with the the phillips head type had the reps tell me to use asds drill in hammer mode to install them worked alright but still had problems they make a bit/drill combo just for that .But if was me I would use the hex head style and let the screw make it own countersink THE ROOFDOC IN MI
I had a project recently that was similar to what you are describing. I used a liquid nail caulking adhesive and I shot 1 inch nails into the concrete. I had to fasten plywood over a concrete area. Once the adhesive dried I had an indestructable sub floor. it was done in a foyer area in a Nursing home with a tile job done over my work. In three years there has been no problems.
Edited 1/1/2003 8:33:04 PM ET by ww_aficionado