View Full Version : A question about drilling concrete and flagstone...
lspencer534
08-31-2016, 4:01pm
I recently posted about some wrought iron fencing I was able to buy. I'm going to install it around a 12' x 12' area of Arkansas Flagstone at my front door. Two sections of the fencing will be installed over concrete. The most secure way of installation (as I understand it) is to drill 3/16" holes in the Flagstone and concrete and screw in 1/4" bolts through the wrought iron posts, which have flanges on the bottoms just for this purpose.
Research tells me to get a 3/16" carbide drill bit and use a "hammer drill" to make the holes. I don't own a hammer drill, but Home Depo has reconditioned ones cheap.
Question: Can I drill through the Flagstone without cracking it? Internet says I can drill through concrete without cracking it if I'm more than 3" from the edge. I am about 4 1/4" from the edges of both the Flagstone and concrete. If the Flagstone can be safely drilled but the slightly larger bolt will crack it, I can always make the hole larger in the Flagstone and then use the 3/16" drill for the concrete below the Flagstone. Make sense?
Jeff '79
08-31-2016, 4:07pm
You can borrow my hammer drill.
I would not use the hammer drill app first.
Try a regular drill first and keep pouring water on it as you're drilling.
Hammer drilling flag stone may crack it and most probably chip it.
How thick is your flag stone?
lspencer534
08-31-2016, 4:09pm
You can borrow my hammer drill.
I would not use the hammer drill app first.
Try a regular drill first and keep pouring water on it as you're drilling.
Hammer drilling flag stone may crack it and most probably chip it.
All the "experts" on the internet say that a regular (non-hammer) drill won't work, that all I'll do is wear out a drill bit. But to do it your way, what kind of bit?
OddBall
08-31-2016, 4:16pm
Diamond bit perhaps, and no hammering
Jeff '79
08-31-2016, 4:16pm
All the "experts" on the internet say that a regular (non-hammer) drill won't work, that all I'll do is wear out a drill bit. But to do it your way, what kind of bit?
I would use a concrete bit, but if it does not work, turn the hammer on.
I have drilled through 2" flag with the hammer on , but it was so thick that I was not concerned about cracking. It goes through like butter with the hammer on.
next week, on As the Spence Turns, "for sale, lightly cracked flagstone, they will make excellent ballast in the bottom of your bass boat"
Jeff '79
08-31-2016, 4:21pm
Just the facts please;
How thick is your flag stone?
What diameter holes are you going to drill ?
Are you saying just use plain 1/4" bolts into a 3/16" bare hole? That's crazy talk. Even if you're talking Tapcon, I would never install railing this way.
You need to use a fastener system. How thick is the flagstone, and what is underneath? I'm guessing that this will be the limiting factor on what you might be able to do.
Are you saying just use plain 1/4" bolts into a 3/16" bare hole? That's crazy talk. Even if you're talking Tapcon, I would never install railing this way.
You need to use a fastener system. How thick is the flagstone, and what is underneath? I'm guessing that this will be the limiting factor on what you might be able to do.
nope, the limiting factor is that Spence is too cheap to hire an expert to do it right, or tell him it cannot be done as planned.
that's where we come in. we're free, but only some of us are experts, but Spence doesn't know which one.
:dance:
Ahhhh, RIF. Concrete under flagstone. That's good. Get youself some sleeve anchors. Make sure they're long enough so that any expansion happens in the concrete, not the flagstone. So, don't anchor to the flagstone itself.
As far as drilling, I'm guessing you'll be at it a long while without the hammer drill, even with diamond bits that will take on tile. The holes you need are small. Drilling away from the edge and going at it slowly with a hammer drill should work as long as the flagstone is relatively thick.
lspencer534
08-31-2016, 4:34pm
Are you saying just use plain 1/4" bolts into a 3/16" bare hole? That's crazy talk. Even if you're talking Tapcon, I would never install railing this way.
You need to use a fastener system. How thick is the flagstone, and what is underneath? I'm guessing that this will be the limiting factor on what you might be able to do.
I was going to use Tapcon bolts. The Flagstone is 2" thick.
lspencer534
08-31-2016, 4:37pm
Just the facts please;
How thick is your flag stone?
What diameter holes are you going to drill ?
The Flagstone is 2" thick, the hole is 3/16", and the Tapcon bolts are 1/4". There is 4" of concrete under the Flagstone.
Jeff '79
08-31-2016, 4:37pm
I was going to use Tapcon bolts. The Flagstone is 2" thick.
You'll be fine with a hammer drill then.
Buy bolts that are long enough to pass through the flagstone and anchor into the sleeve anchors that are sunk into the concrete.
Zip-Zap is right on the money.
lspencer534
08-31-2016, 4:39pm
next week, on As the Spence Turns, "for sale, lightly cracked flagstone, they will make excellent ballast in the bottom of your bass boat"
Reporter to Astronaut: "Is that a crash helmet you're wearing?"
Astronaut: "Oh...I hope not...."
Remember Jose Jiminez?
OddBall
08-31-2016, 4:39pm
Ahhhh, RIF. Concrete under flagstone. That's good. Get youself some sleeve anchors. Make sure they're long enough so that any expansion happens in the concrete, not the flagstone. So, don't anchor to the flagstone itself.
As far as drilling, I'm guessing you'll be at it a long while without the hammer drill, even with diamond bits that will take on tile. The holes you need are small. Drilling away from the edge and going at it slowly with a hammer drill should work as long as the flagstone is relatively thick.
3/16 is still pretty thin for an anchoring bolt. Even with the anchor sleeves, and even if there are several bolts per each rail foot.
Anchor sleeves are a definite. Get the good ones, not the cheap ones.
Also, is the top end of the fence supported anywhere? A post? A wall?
If not, those bolts to the stone and concrete are not going to hold up to people leaning on the fence. And people will lean on the fence. Especially kids. The bolts will eventually work themselves free.
Jeff '79
08-31-2016, 4:42pm
3/16 is still pretty thin for an anchoring bolt. Even with the anchor sleeves, and even if there are several bolts per each rail foot.
Anchor sleeves are a definite. Get the good ones, not the cheap ones.
Also, is the top end of the fence supported anywhere? A post? A wall?
If not, those bolts to the stone and concrete are not going to hold up to people leaning on the fence. And people will lean on the fence. Especially kids. The bolts will eventually work themselves free.
tru dat. 9/16" bolts would be wayyy better.
lspencer534
08-31-2016, 4:46pm
3/16 is still pretty thin for an anchoring bolt. Even with the anchor sleeves, and even if there are several bolts per each rail foot.
Anchor sleeves are a definite. Get the good ones, not the cheap ones.
Also, is the top end of the fence supported anywhere? A post? A wall?
If not, those bolts to the stone and concrete are not going to hold up to people leaning on the fence. And people will lean on the fence. Especially kids. The bolts will eventually work themselves free.
The posts are not free-standing. On one end, I will drill a 1/8" hole in the top 2" of the post and screw the post to wood that the post butts up against. I'll do the same at the other end except I'll use the screw to go into mortar.
Jeff '79
08-31-2016, 4:51pm
nope, the limiting factor is that Spence is too cheap to hire an expert to do it right, or tell him it cannot be done as planned.
that's where we come in. we're free, but only some of us are experts, but Spence doesn't know which one.
:dance:
:iagree: Although with a little research, he can save a lot of money, possibly do it right, and enjoy a trip to the hospital.
WIN, WIN, WIN !
OddBall
08-31-2016, 4:53pm
The posts are not free-standing. On one end, I will drill a 1/8" hole in the top 2" of the post and screw the post to wood that the post butts up against. I'll do the same at the other end except I'll use the screw to go into mortar.
:seasix:
I'd put the screws at least in pairs you can. If not, double the size of the screw.
I was going to use Tapcon bolts. The Flagstone is 2" thick.
Don't do that. 2" is good thickness.
I would go with this: 3/8" x 4" Strong-Tie Sleeve-All Anchors, Hex Head, Zinc Plated, Pkg 50 (http://www.fastenersplus.com/3-8-x-4-Strong-Tie-Sleeve-All-Anchors-Hex-Head-Zinc-Plated-Pkg-50)
If you are restricted to 1/4", then I would go with this: 1/4" x 1" Strong-Tie Drop-In Anchor, Zinc Plated, Pkg 100 (http://www.fastenersplus.com/1-4-x-1-Strong-Tie-Drop-In-Anchor-Zinc-Plated-Pkg-100) and use whatever 1/4 - 20 bolt you like. If you go this route, be sure to get a setting tool for the anchors, and get anchors without lips so they will drop through the flagstone and into the concrete.
OddBall
08-31-2016, 4:56pm
:iagree: Although with a little research, he can save a lot of money, possibly do it right, and enjoy a trip to the hospital.
WIN, WIN, WIN !
He can handle it. I built a shed all by myself. Didn't go to the hospital. Not even once.
Cussed a lot though.
A lot.
:iagree: Although with a little research, he can save a lot of money, possibly do it right, and enjoy a trip to the hospital.
WIN, WIN, WIN !
and while he's getting patched up, he can gin up some business in the ER. pass out some cards, take some preliminary statements, see if there is someone rich who should be sued. don't forget to pack clean underwear and about 30 business cards!
Don't do that. 2" is good thickness.
I would go with this: 3/8" x 4" Strong-Tie Sleeve-All Anchors, Hex Head, Zinc Plated, Pkg 50 (http://www.fastenersplus.com/3-8-x-4-Strong-Tie-Sleeve-All-Anchors-Hex-Head-Zinc-Plated-Pkg-50)
If you are restricted to 1/4", then I would go with this: 1/4" x 1" Strong-Tie Drop-In Anchor, Zinc Plated, Pkg 100 (http://www.fastenersplus.com/1-4-x-1-Strong-Tie-Drop-In-Anchor-Zinc-Plated-Pkg-100) and use whatever 1/4 - 20 bolt you like. If you go this route, be sure to get a setting tool for the anchors, and get anchors without lips so they will drop through the flagstone and into the concrete.
With the second solution, you could also go all stainless for more money and not worry about corrosion.
09SilverC6
08-31-2016, 5:27pm
i use a hammer drill on flagstone alot , a sharp bit will turn the cutting into butter....
mrvette
08-31-2016, 7:36pm
This is a funny thread, the guy next door is a totally incompetent home mechanic/remodeler, he dunno shit and has limited tools.....
so he comes over with a burnt out carbide bit he tries to drill some tile in a shower to hang a door.....he dunno what a drill/hammer is....so I loan him mine...he brings it back saying it won't go through the tile.....a lousy 3/16th bit through WALL tile?? with a 1/2 inch drill hammer???
So I just take it back yesterday with a smile......his house looks like crap, really inside and out......
It's CLEAN and all, but he has all this ambition and no talent.....:issues::rofl:
vBulletin® v3.8.4, Copyright ©2000-2025, Jelsoft Enterprises Ltd.