Epoxy a stud into concrete

[Packard]

The concrete slab already exists. 

I purchased this hardware to mount 4” x 4” pressure treated post 8’ tall.

I also purchased the mounting studs which are 1/2” x 5” hot dip galvanized and are specified for this bracket.

My largest diameter masonry bit is 1/2”.  I drilled to the full depth and tested the fit.  It is a slip fit.

There are no instructions with either the stud or the bracket.  The 1/2” diameter hole does not leave much room for epoxy.

QUESTION # 1:  What diameter hole do I need to use for this application?

QUESTION # 2:  There is a special epoxy that is in a caulking tube. I have only one bolt to set.  Do I need to use that special epoxy?

The post is anchored at the top and will be anchored at the bottom.  The purpose of the stud is to keep things in alignment. 

 

[Tom the Remodeler]

Hi Packard,

There are of course dozens of solutions for this scenario, and of course it would be helpful to know more information regarding the specific performance needs, but you'd probably be fine with a 1/2" masonry fastener like this:https://www.homedepot.com/p/Simpson...Heavy-Duty-Screw-Anchor-THD50500HF1/300690848

Or, you can use a wedge anchor like this:https://www.homedepot.com/p/Red-Hea...ut-Head-Concrete-Wedge-Anchor-50181/308292398

The epoxy process is more commonly used for threaded rod, and yes for structural applications there are requirements regarding the annular space around the fastener for optimal performance.

 

[live4ever]

The epoxy is usually a two component system and yes, may go to waste if you just have one stud to set.

Personally I’d just go with a wedge anchor if this is a small and straightforward project.

 

[Packard]

I saw these when I shopped for the brackets.  Ill give them a try.

The epoxy did not allow for multiple uses.  It was one-and-done.

Thanks for the replies.  I’ll let you know how it works out.

 

[Tom the Remodeler]

Packard,

I forgot to mention that the concrete screw I linked is generally best installed with a 1/2" impact wrench, not sure if a normal drill/impact driver would have the oomph. Also, it is generally a "one-and-done", since the steel threads are cutting into the concrete. They are removable, but reusing the screw or hole may not have the same performance characteristics as the first time.

The wedge anchor is generally more user friendly, though you might need to cut the top part of the stud after tightening the nut.

Curious to hear what you come up with.

 

[live4ever]

Here’s a simple project I did last year.  7x7’ porch overhang supported by a 4x4 post at one corner.  The redwood post was set into the ground in large gravel, and surrounded by bricks.  It had rotted (obviously) causing the corner of the porch overhang to droop by 3 inches.  I poured a small base of concrete and set a precast pier block on it.  Drilled into the pier block and installed the bracket with a Red Head wedge anchor.  Used a wedge exactly for the reason Tom stated - didn’t want the “one and done” aspect of the screw.