Home Improvement

Drilling porcelain tile to secure new toilet flange

By August 20, 2019 8 Comments

I’m probably over thinking this, but having never drilled tile, plus the nature of where it is, I have essentially one shot and don’t want to crack the tile or drill too large.

I need to secure a new toilet flange to new tile. I got some 3/16 x 1 3/4 tapcons. What size hole do I predrill?

My choices seem to be:

1) Tapcon’s package says to use 5/32. These only seem to be readily available here as a tapcon branded bit and they don’t seem to be made for tile. They’re for concrete.

2) 3/16. It matches the size of the anchor. I figured it’d be just that simple but on second thought, I figured I’d need to leave some meat for the anchor to grab on to.

3) 1/8. Just smaller the tapcon recommended 5/32 so maybe it’s good enough.

I know I’m almost literally splitting hairs and overthinking but I’m worried if I do a pilot hole that’s too small, the anchor will crack the tile as it grabs on and wedges in. But if I drill too big, there’s nothing to grab onto.

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  • m0nsterhuntr says:

    What sort of subfloor is under your tile? Could you drill bigger then use a fastener that is appropriate for the subfloor material? Simply passing through the tile without fastening directly to it.

  • Sernix1 says:

    Is there a concrete slab under the tile or wooden sub floor?

    You can’t just secure the flange to the tile it’s not strong enough.

    If you’re dealing with a slab just get a tile bit and make a pilot hole through the tile the use the correct bit for the tapcons in the slab.
    The hole recommend by tapcon is a pilot hole it’s not meant to be as big as the screw itself.

  • 87880917 says:

    I’d only recommend using tapcons if your home is on a slab, and I’d probably go with 2 1/2” so you know your tapcon is anchored into the slab and not just the tile itself.

    If you’re *not* on a slab, then you’ll want your fasteners to go through your tile and sink into your subfloor. In this case you’d want to use screws that won’t rust, so 2 1/2” galvanized or zinc plated screws will get the job done.

    And they sell drill bits made for glass & tile that I’ve had good luck using on porcelain tile without cracking it.

    But most importantly, don’t rely on the tile to hold your fastener. Make sure you go all the way into whatever is beneath your tile. And don’t overtighten anything either or else your tile might crack.

  • bunjay says:

    >I need to secure a new toilet flange to new tile

    Why do you think you need to mechanically fasten the flange at all?

    Anyway, if this is the very hard porcelain I’ve often had to drill through regular masonry bits are pretty much useless. The arrowhead style bits are much, much faster but only good for about 2 holes each. 1/4″ diamond hole saws are faster than either and only start to slow down after 4 or 5 holes and are good for 10+.

  • jegarvey1 says:

    They make diamond drill bits for the tile, make sure to use water so they cut better. But if you’re going through to wood subfloor you won’t use tapcon

  • Rock_it_Scientist says:

    I literally just did this last week but I was going onto a slab instead of a hardiback/subfloor like you.

    I used a masonry bit and went slow. It took a little while but I didn’t shell out the cost of an expensive bit for drilling porcelain tile that I won’t do again for a long time. What you need to make sure of is that the hole in the tile and morter is a clearance hole and not a hole that the screw secures to. You will crack a tile if you try to set a screw into it (ask me how I know).

    You just need to buy some stainless wood screws or those backer screws they make for cement board or hardibacker. Nothing should be tied to the tile, just passes through the tile.

  • arc2v says:

    Agree with just about everyone here and I’m going to be doing this in the next week or so.

    Definitely use the diamond bit if you can get one. They go through tile much better than masonry bits. Porcelain can be very hard and keep the cutting surface cool. The heat is what cracks tile and wears bits faster. So take your time. It might take a minute per hole, but that’s better than splitting a tile or having to buy another $20 bit.

    And yes, always secure to the subfloor. If you haven’t purchased the flange yet, the plumbers always seem to recommend the stainless rings over the all-plastic flanges. The ring won’t corrode and is much stronger.

    Good luck.

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