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Anchor bolts - concrete vs epoxy

Dsoniat's picture

Hi folks.  i got a rear porch (about 15 x 30) which is open on 2 sides.  there are 3 square, steel posts along the 30 foot run holding up the roof.   note: this is part of the main roof of the house, not a porch roof.   i live in florida and i'm concerned about hurricane winds.

now the house was built in late 1980s and i can see steel hurricane strapping on walls and connecting rafters to top plates, etc.   however, i can't see anything holding the roof down to these square posts except tiny decorative brackets.

i'm putting steel plates bolted through the posts and lagged into the wooden beam above.

however on the bottom, the only thing i can do on 2 of them is use steel "L" brackets and anchor them to the slab (porch floor).

after all question:   what's the best way to anchor those brackets to the floor?   drill holes and set bolts in concrete?  or use something like all-thread glued with epoxy?

Thanks much for any insight!

(post #101824, reply #1 of 18)

The epoxy method works well, but use the right product.  One example would be Hilti.  Check their websitr, they have anchor bolts where you drill an oversize hole, squirt in the epoxy, then push the allthread or bolt in place.  When it sets up it meets all the codes ... if you followed the directions.


"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

"Put your creed in your deed."   Emerson

"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it."  T. Roosevelt

(post #101824, reply #2 of 18)

I agree that epoxy & all thread is the best solution.  Depending on the performance you are looking for you might get what you need with a mechanical wedge anchor.

Look at the Red Head A7 adhesive or the Red Head Trubolt wedge anchor.


(post #101824, reply #3 of 18)

I think i'd drill all the way thru the slab... and use the hilti anchors that have the cross bar the flips down to form a T

  i've seem them 12" long


(post #101824, reply #4 of 18)

Be careful if setting expanding[mechanical] anchors close to the edge of a slab. You could split off a chunk of concrete. Another vote for epoxy.

(post #101824, reply #5 of 18)

Epoxy is the way to go.

Simpson sells their version at Home Depot, and they make a cartridge that fits in a standard caulking gun (good if you only have to do a few holes). Be careful not to break through the bottom of the slab, or your epoxy will run out the bottom of the hole.


(post #101824, reply #6 of 18)

Just make sure you read the instructions.

(post #101824, reply #7 of 18)

Another vote for epoxy. Simpson Tie sells different lengths of galvy allthread with a nut and washer on the end for this situation. 

(post #101824, reply #8 of 18)

Yes, epoxy, no expansion bolts.  Since you are in Florida is corrosion a concern?  Stainless steel bolts and nuts would be a cheap upgrade.

(post #101824, reply #9 of 18)

In doing remodels and additions, we would often have to stab in some allthread.  From what I read (I'm tired, so maybe I'm off a bit) but it seems like epoxy and allthread is the best bet.  Around here, the easiest stuff to find is the Simpson SET 22, which is I believe the structural stuff.  We drilled out the holes 1/8" bigger than the rod diameter to allow the epoxy to grab.


Young, poor, and eager to learn


(post #101824, reply #10 of 18)

Folks,  just want to thank everyone for their responses.   over the weekend we drilled and set all-thread using the simpson epoxy.   it worked great and was a pleasure to use.

thanks again.....David S.  (Tampa, Fl).

(post #101824, reply #11 of 18)

I think I'll be using the advice in this thread to mount a rail on some solid concrete blocks too Dsoniat! I've never worked with expoxy but your experience gives me hope.




keep looking for customers who want to hire  YOU.. all the rest are looking for commodities.. are you  a commodity ?... if you get sucked into "free estimates" and  "soliciting bids"... then you are a commodity... if your operation is set up to compete as a commodity, then have at it..... but be prepared to keep your margins low and your overhead  high...."

From the best of TauntonU.

(post #101824, reply #12 of 18)

To blueeyeddevil and several said in this discussion, read the instructions.   they were not too informative (mostly just iconic pictures on the side of the package and terse words like:  "Drill", "Clean", etc) but they helped.

i did drill, clean, brush out the holes and hit them with the air (blow-gun).  i'm sure any caked on cement dust might have diminished the hold the epoxy would have on the concrete so get them clean.  also, (although i found no mention of it)  i would assume that any wetness to the concrete would cause problems with the attachment.

the package said the epoxy would cure in 5-7 min.  i seemed to have much longer working time than that.   getting it down into the holes without trapped air required working each bolt up and down quite a bit.  it was obvious when the air was out (no springiness left).

one other thing, once finishing up i had a fair amount of product left in the gun which went to waste.  don't lay the gun down and come back and pick it up again in about 20'll find out it will be at about 200 degrees (don't ask how i know)....

(post #101824, reply #13 of 18)

What?! Nobody uses Rockite anymore?! I'm no engineer, but in my experience, that stuff holds like a mf'er. Really simple to use and it's a hell of a lot cheaper than epoxy.

(post #101824, reply #14 of 18)

Back in the 50's we used to pour melted sulfur in the holes to set bolts. Then anchored 30-40ton pieces of machinery with the bolts. It never moved.

New stuff not always the only way or the best way.


If you have a problem, don't just talk do something to set it right.

  Jim Andersen

(post #101824, reply #15 of 18)

I don't think you were worried about wind uplifting 30 or 40 ton equipment. I agree with questioning new methods though- our "Big Dig" Project in Boston didn't have great success with properly setting epoxied bolts to hang concrete ceilings. We are all waiting for the new improved roadways to reopen, and one unlucky woman has been killed because of it!

(post #101824, reply #16 of 18)

Actually the sulfur exoands on cooling like Ice I it will lock any thing in place as long as temp isn't above 300 deg.

If you have a problem, don't just talk do something to set it right.

  Jim Andersen

(post #101824, reply #17 of 18)

rockite!! my favorite...i use it for anchoring in concrete on a regular claims to have more strength than regular concrete...and the stuff it hard as a rock in about 10 minutes...i'm in Bermuda, and construction down here is pretty much all concrete/block...i am curious about this epoxy stuff everyone seems to like so much...i will look into it for sure...but seriously tho...i don't see how a bolt set in to concrete/rockite is ever gonna move, and i'm pretty sure the epoxy isn't cheap at all, especially to use on a regular basis...

any other good/bad experiences with either rockite/epoxy?

"Allthread" is just a bolt (post #101824, reply #18 of 18)

"Allthread" is just a bolt threaded the full length sold for structural applications?