# Forum Home Renovation Decking  Advice needed for drilling hole into 20mm bluestone pavers on concrete

## barrysumpter

Sorry I'm not sure what forum to post this on. 
A continuation of this thread: http://www.renovateforum.com/f209/ex...17/#post950435 
I've hade my concrete porch and stairs covered with tessellated tiles and 20mm bluestone pavers. 
I'm now installing the balustrade for the stairs. 
I've purchased U shaped stirrups to bolt to the bluestone for the 4 posts. 
The bluestone pavers have been professionally layed on top of the concrete porch. 
The porch concrete does have some significant rebar(?) embedded for reinforcement strength.
My builder was quite impressed with the way the porch was built.
And how long its lasted with very little cracking (before getting tiled).  
I need some advice for drilling the holes for the stirrups 
1) thru the 20mm bluestone 
2) thru the glue between the bluestone and concrete porch
3) thru/into the concrete porch
4) worst case (to me) thru the rebar 
Any positive constructing advise would be greatly appreciated. 
tia

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## Marc

There is only one way to drill through pavers and concrete and that is with a good size rotary hammer and concrete drill bit according to the size of the bolt you are going to use. Because of the bluestone pavers being prone to crack, you can do a pilot hole first of a smaller size. That will also help to correctly position the holes. The glue is of course of no concern nor is the concrete, but the rio is. If you hit rio, the drill bit will tend to go sideways since it can not cut the steel. You can sometimes drill through the rio by changing to a steel drill bit but it is a hit and miss affair. If you add up the thickness of the paver the glue and the concrete that is above the rio, may be you don't have to worry about the steel bar and your bolt will live above it.

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## barrysumpter

Hi Marc,  Thanks for the super fast response.
Can't wait to get started on this project  32 degrees today.  
Concrete drill bit not the same as brick drill bit?
Rotary hammer not the same as electric drill with hammer switch?  
Exposed concrete pad or footing
------------------------------------
For this application a screw bolt or sleeve anchor is best. The suggested size for both involves drilling a 12mm diameter hole. The length of the fasteners may need to be adjusted depending on the thickness of the concrete pad.  
Bluestone paving
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Attaching to bluestone pavers should be avoided if possible. If required the application is similar to the exposed concrete pad with the exception that some care is required when drilling the holes. As a general rule drilling into bluestone should be slower and cooled away from the edge of the paver to avoid cracking.

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## barrysumpter

Balustrade Rules

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## Marc

Drill bits for concrete or brick are the same as far as I know. There are differences in quality like everything. 12mm is a decent size hole and I doubt you can do it with a hammer drill. Well, you can if you need to do a few I suppose. The rotary hammer has a piston and gives the bit a decent whack. The ordinary "hammer" drill holds the bit in a chuck and rubs against a grooved plate to give it a bit of a vibration. It works OK for bricks but lacks the oomph required for concrete.  A rotary hammer holds the drill bit with one of the SDS system, according to size.  
As far as fastening systems I am far from being an expert. All I know I hate dynabolts particularly the small wimpy ones. I agree that holding only in the paver is a bit risky, but you have to do with what you have.  Drill as deep as you can to grab hold of the concrete. The reo bar is another consideration, but what choices do you have? If you go deep you may hit a reo. If you stay shallow your hold is lacking.
I had to deal with reo in concrete only a few times and it was a pita yet I did it with a steel drill bit (and destroyed it) There may be other ways to do it more professional that I am not aware of. You will definitely need a decent size rotary hammer and SDS drill bits.
I wonder if it is possible to sharpen a masonry drill tip and use it only on the reobar when you hit it? Never tried that myself.

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## barrysumpter

Thanks heaps Marc.
Really appreciate the verbose replies. 
Pretty much everyone has been telling me to give it a go with the home drill with hammer switch.
If it doesn't work very well rent a rotary hammer.
$50 including drill bit.  And 20% off if I return within 4 hours.
Then of course I ask should I use that $50 to invest in a ozito rotary hammer and have it and take my time with and have it on hand next time.
The lady tell me no.  LOL

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## shauck

Tell her you hired it and then hide it in the shed later.

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## Marc

Ha ha that sounds familiar ... don't tell me you have to do that yourself?

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## shauck

No, I'm allowed to buy tools. I'd have to reconsider the relationship otherwise.  :Cool:

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## shauck

I must say tho, every couple of years the bigger tool buys are for my birthday or christmas so that makes it better.

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## r3nov8or

Buy a cheapie and take your time. Nothing worse than a time limit on unfamiliar work. Other uses like light demolition, tile removing etc make it a handy tool to have.

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## Marc

And as far as Ozito rotary hammer goes, even when I don't own one, I bought one for an electrician friend and he seems to use it a lot and happy with it.
By the way ... anyone has any experience of how to deal with hitting reobar when drilling into concrete?

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## phild01

> By the way ... anyone has any experience of how to deal with hitting reobar when drilling into concrete?

  Some time back when I bought a standard 12mm masonry drill bit it was rated to go through the reo as well.  Had no problems with it.

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## Bloss

On tiles I would NOT be using a big hammer drill with tungsten carbide masonry bits, but getting some diamond bits and trying at least at first to use without hammer action. Or hire a diamond clamping/drill kit to do the job. Fair chance otherwise that you will crack off the edge of the bluestone, the concrete or both. And most diamond bits will cut through the reo - carbide will change direction and try to go around - often then causing cracks - or at least a crooked hole (or a broken bit or both!).

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## barrysumpter

> Tell her you hired it and then hide it in the shed later.

  LOL
We call that lying.   
Cracking the bluestone would not be good at all. 
Have a 10mm bolt hole to drill.
I've picked up a 5mm bit for pilot hole.
I've picked up a 10mm bit - 75mm long for dynabolt 
They only stocked 50mm then 75mm lengths. 
I'll be looking into diamond bits.

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## Marc

https://www.etsy.com/au/listing/1801...CX0aAtpi8P8HAQ 
Interesting, never used one of this. Needs water

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## barrysumpter

Thanks to all for replying. 
Ok, yeah.
I'm feeling it now.
Diamond Coated Core Drill Bit
Normal drill NOT on hammer setting.
That'll save me some money I think.   
Bunnings:
The P&N Drill bits have diamond encrusting to cut through glazed and polished porcelain, sandstone, terracotta and ceramics.
Suitable for tiling, plumbing, electrical, building trade and DIY handy person applications. 
For wet drilling only
Cuts to ±0.2mm tolerance
Never use the power tool on hammer setting
To avoid drill slipping start drill at a 45º angle, and gradually straighten the power tool 
So we're thinking it's less likely to crack the bluestone tiles?   http://www.dynatech-diamond.com/drilltips.html   
Darn.  These cutting depths are not 75mm (3").
Maybe some washers?  grrrrr 
Oh, or maybe just enough to get thru the 20mm ( 7/16 ) of bluestone tiles?   http://www.bunnings.com.au/tile-dril...amond_p6820162

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## barrysumpter

Thanks to all. 
OK Done.
All good. 
No tear out or cracking or breaking. 
My tiler suggested carbide tipped.
Taits only had diamond tips. 
My tiler also told me 50mm from the edge to prevent cracking and breaking. 
Three or four different shades of debris coming up. 
10mm Diamond tipped core drill $16 to depth of 20 mm.
45 degree angle to start.  Then 90 degree.  With a drizzle of constant water. 
8 holes using makita cordless 18v lithium ion 3 ah on a single battery. 
Then 10mm masonry bit $8 to finish the 85 mm using Bosh blue electric with hammer switched on. 
No rebar as far as I know.
Could have been old enough where rebar has lost its strength and I wend right thru. 
Thanks heaps to all.

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## Bloss

Good result and good advice from your tiler, especially if you were able to get that far away from the edge and mostly pretty safe at around 30 mm or more. As you have seen most of the advice is conservative - as none of us like to see good work damaged and even the most experienced of us have had that happen even with the best drills, bits and skill! 
Be good to see a pic!

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## barrysumpter

Really comfortable with the 50mm.    
Already Dyna bolted in. 
Steps need to be washed off from all the residue. 
That DAR post will be traded in for a custom turned newel to match the other posts. 
Two to three weeks for delivery so the stirups will have to stay until then.

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## r3nov8or

Bloss, well done on the advice re the drilling of the bluestone safely. Many of us were focussed on the concrete and the reo...

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## barrysumpter

Stumbled upon this in between photo. 
The masking tape was for my measurement layouts. 
No easy to decide on where the bolt holes go when everything is off centre etc.

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