Drilling 3/4" hole into brick


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Old 06-16-24, 08:50 PM
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Drilling 3/4" hole into brick

I am installing a short 3-foot long exterior handrail to my brick exterior. The two brackets for the handrail fasten with a 1/2" lag screw in a lag shield which requires a 3/4" hole. My question is where to hammer drill on the brick face to avoid cracking the brick. The brick is only 2-1/4" (height), therefore I can never be further away than 3/4" from any edge. There are also limitations based and rail height and where I place the brackets along the short run of railing.

How close can you usually drill to the brick edge and avoid cracking the brick? Is there any advantage of drilling a pilot hole prior to the final 3/4" hole to minimize the chance of cracking.

Thanks in advance for any input. There isn't much trial and error unfortunatley so I thought I'd ask people who already have experience.

Proposed railing location



 
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Old 06-17-24, 03:46 AM
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I think you can go to a smaller diameter hole by using sleeve anchors. Avoid locating anchors in mortar joints.
 
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Old 06-17-24, 05:54 AM
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I've had too many bricks or the grout joints crack when using larger (5/16" and up) size expansion anchors. Instead, when a large size fastener is needed, I use the type you epoxy in place.
 
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Old 06-17-24, 09:44 PM
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Thanks for info about avoiding mortar joints and the epoxy fasteners. I'm going to look into that. When you've had bricks crack, did it happen during drilling or from the expanding fastener?
 
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Old 06-18-24, 05:14 AM
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Cracks can happen at any time, especially when using a hammer drill or rotary hammer. But, usually the cracks appeared when tightening the expanding anchors. Expanding anchors work by the same method used to split rocks.

Small plastic inserts used with screws are generally OK as they don't exert as much pressure on the bricks. But, when you get up to proper expanding anchors, and especially larger ones you are dealing with a bigger hole and more expansive force holding the fastener in the hole.
 
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Old 06-23-24, 01:38 PM
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Just out of curiosity, when you start talking about larger holes for expanding anchors (like 3/4") does the thinking change as to whether you would insert into brick or mortar joint?

If you drilled a 3/4" hole in the center of a horizontal mortar joint then you would only be removing a small portion of brick on the top and bottom of two different bricks. If the anchor was placed to expand vertically, then you would be applying pressure to two separate bricks towards the center of each brick, rather than into the center of a single brick and sending the force outward. I totally understand that mortar joints are not good options as compared to brick anchors, but a larger expansion anchor really wouldn't be relying on the mortar material alone.

I haven't attached the the railing yet, but am excited about switching the mounting-type from expansion anchor to threaded rod with epoxy. I haven't done that before. As I was laying out the holes I started thinking how a large expansion anchor (larger than width of mortar joint) might be better to center within the joint and have the force directed from the outside of two separated bricks. I'm not sure if that has been tried successfully before?

Thanks!
 
 

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