Drilling in concrete

I've had no experience with drilling into concrete. From what I read, after drilling the pilot hole with a hammer drill, I should install an insert. But this seems to be only if you want a threaded screw protruding from the wall to hang things on, like a TV mount.

I'm going to anchor a toilet closet flange to a concrete slab, so I don't need or want anything protruding from the floor. So after drilling the pilot holes, do I just insert the screws/anchors into the holes?

I'll be using the Push Tite closet flange shown here:

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I originally thought the snugness of the fit would give a sturdy installation, but the instructions say to always fasten it to the floor. There are eight holes for accepting flat-headed screws, but only four are needed (the two at the ends of the bolts slots, or the two adjacent to the bolt notches).

Thanks,

R1

Reply to
Rebel1
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You want to use TapCon screws , and the appropriately sized masonry drill bit . Available at any half-way decent hardware store .

Reply to
Terry Coombs

That is the brand I have (bit and screws). But the question is do I need an insert to fasten the flange to concrete?

Reply to
Rebel1

No , the TapCon is designed to TAP it's own threads into CONcrete . You'll need a pretty decent screw gun or impact driver .

Reply to
Terry Coombs

Thanks. That was the answer I was hoping for.

Reply to
Rebel1

Rebel:

Tapcon screws are unique in that they can be driven into a pilot hole drilled into concrete without using a plastic or lead anchor to hold the screw.

But, for your purpose, I wouldn't use them. They're ordinary steel, and in that application they'd rust out in a few years so that you'd never be able to get that toilet flange off if you needed to.

If I were me, I would: a. drill pilot holes for the toilet flange to a depth of about 1 1/2 inches

b. enlarge those holes with a 5/16 inch masonry bit and vaccuum the dust out of the holes by inserting a drinking straw in the suction hose of a vaccuum cleaner.

c. insert 5/16 inch diameter by 1 1/2 inch long lead anchors into the holes so that the tops of the lead anchors stick out a little bit from the concrete floor.

d. Use a counter sinking drill bit to cut the tops off the lead anchors so they don't protrude above the concrete. Counter sinking bits are typically used on wood so that the heads of flat head screws are flush with the surrounding wood. But, lead is such a soft metal that the counter sinking bit won't have any problem countersinking lead.

e. Screw your floor flange down with STAINLESS STEEL flat head size # 10 or # 12 sheet metal screws. (See PS below.)

You should be able to find 5/16 inch diameter by 1 1/2 inch long lead anchors at any hardware store or home center. Ditto for the stainless steel screws and ditto for the counter sinking bit.

If you're not following this game plan, Google "5/16 inch lead anchors" and "countersinking bit" to see what they look like, and it should all become apparant to you.

This way, neither the lead nor the stainless steel are going to corrode so you don't have to worry about facing real difficulties if you ever crack that floor flange and need to replace it. With badly rusted ordinary steel screws holding it down, you might have a real fight on your hands getting those old steel screws out. With stainless steel screws in lead anchors, you'll not have any problems replacing the floor flange in future if necessary.

PS: The difference between a wood screw and a sheet metal screw is that the wood screw will only be threaded over 2/3 of it's overall length. Sheet metal screws are threaded right up to the head of the screw. Most handymen use sheet metal screws for just about everything and rarely, if ever, use wood screws. The name "sheet metal screw" gives a mental image of being small, but sheet metal screws come in all the same sizes that wood screws do.

Reply to
nestork

I've also found (DAMHIKT) that a hammer drill works much better on masonary. Also good to use a bent out paper clip as a depth gage, to be totally sure the hole is deep enough for the tapocon you're using.

Reply to
Stormin Mormon

I've used tapcons once, to anchor down an aluminum threshhold for a loading dock of a store. I found an impact driver sure helped to turn the screws. Borrowed a Black and Decker one from a friend, and got myself a HF impact driver after that. Oh, helps to wax the threads heavily before turning them in. Tube of lip balm from the dollar tree is much cheaper than the $5.69 bit of bees wax from True Value.

. Christopher A. Young Learn about Jesus

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Reply to
Stormin Mormon

I think the point that people seem to be missing here is that Tapcon screws are ordinary (perhaps hardened) stell. They rust. They have a coating on them that would help prevent rusting, but eventually, they'll rust.

The OP can use Tapcon screws to hold the toilet floor flange down, but if he ever needs to replace that floor flange, and isn't able to get those old rusted screws out of the concrete, he'll have to grind them off flush with the concrete, and drill new holes in his floor flange to hold it down.

I say it's smarter to use lead anchors and stainless steel screws to avoid that situation in the first place.

Reply to
nestork

As was stated by Nestork, I also agree you should use lead anchors. The anchors will remain and you can use never seize on the bolts. When/if the time comes to replace the toilet again, you can unbolt much easier. Tapcons WILL rust and WILL break when the time comes to replace. Also, Tapcons can break while screwing them in unless you use a lubricant. If they break while screwing in, good luck getting it out. It will ruin your entire day.

Reply to
Meanie

Excellent points I hadn't considered. For rust to form, there must be a combination of moisture and oxygen. I'm not sure both those conditions exist much below the screw head, but even if found only just below the screw head, it could snap the head if trying to remove the screw. Deeper down, I'm not sure if rust would form to resist removal torque.

If the wax ring covers the screw heads, the problem would be less likely as both moisture and oxygen would be missing at the heads.

Like with concrete screws, I never worked with lead anchors before. Either way, it will be a learning experience for me.

Thanks,

R1

Reply to
Rebel1

Thanks for the highly detailed description of sizes and tips. This is the way I will go.

R1

Reply to
Rebel1

See if Harbour Freight sells a "Rotary Hammer".

There are two types of "hammer drills";

Percussion type hammer drills and Rotary Hammers

Percussion type hammer drills are OK for drilling into soft masonry like bricks and brick mortar, but aren't really meant for hard masonry materials like concrete and hard stone like granite.

A rotary hammer will drill into soft masonry AND hard masonry like concrete very much faster and easier than a percussion type hammer drill. But, good quality rotary hammers will use a different style of chuck than percussion type hammer drills. Percussion type hammer drills will use the same kind of chuck that an ordinary electric drill uses. Rotary hammers will use something called an "SDS" chuck. You need to buy special SDS drill bits to use in an SDS chuck.

What you might want to do instead of buying a percussion type hammer drill from Harbour Freight is to phone around to your local auction houses and see if they're auctioning off any tools. You'd be able to buy a used rotary hammer at an auction sale for about the same price as a new percussion type hammer drill at Harbour Freight, and any good quality rotary hammer will be vastly better for drilling into concrete than any percussion type hammer drill.

Reply to
nestork

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