Fixing broken cap on step

[Zeke]

The fabricator won't drill a hole or 4 in their stone step? What does that tell you? Tells me they don't like the idea to begin with.

OK, so that's said and done. Now back to what rlitman said, use a rotary tool that doesn't beat on the corner as much as a hammer drill and certainly not an SDS. BTW, SDS will drill w/o the hammer. At least mine will. So you could possibly do this with a new carbide bit and water. Water with anything you do to lube and cool the operation. A consideration is to use successively larger bits.

I don't like the Tapcon idea only because they exert outward pressure and it's stone, there could be existing stress cracks, or new from drilling. If you successfully get the holes drilled, be thankful you got that far.

From what I can tell, the left side railing is already fabbed up and ready to install in the same manner as the RH one, i.e., a plate with four holes. I'm going to stand pat on my idea of sinking all thread in epoxy. According to rlitman, the strength of the thickness of the stone is enough. He could (and usually is) right, but if you're drilling holes, you might as well drop the all thread in deeper so you can cinch up nice and tight once the epoxy reaches full strength. I doubt you will be using anything larger than 5/16ths" in a 3/8ths hole.

Just as a reminder, I mentioned using water while drilling. You could use fast set while the hole is still damp. Not so with epoxy, it has to be bone dry (the kind I'm thinking of — A and B mix. Simpson makes a good one in a tube.). There are epoxy modified setting compounds but I'm not all that familiar. For those you need a hole big enough to pour the mixture in.

 

[rlitman]

...use a rotary tool that doesn't beat on the corner as much as a hammer drill and certainly not an SDS. BTW, SDS will drill w/o the hammer. At least mine will. So you could possibly do this with a new carbide bit and water. Water with anything you do to lube and cool the operation. A consideration is to use successively larger bits.

I don't like the Tapcon idea only because they exert outward pressure and it's stone, there could be existing stress cracks, or new from drilling. If you successfully get the holes drilled, be thankful you got that far.

From what I can tell, the left side railing is already fabbed up and ready to install in the same manner as the RH one, i.e., a plate with four holes. I'm going to stand pat on my idea of sinking all thread in epoxy. According to rlitman, the strength of the thickness of the stone is enough. He could (and usually is) right, but if you're drilling holes, you might as well drop the all thread in deeper so you can cinch up nice and tight once the epoxy reaches full strength. I doubt you will be using anything larger than 5/16ths" in a 3/8ths hole.

Just as a reminder, I mentioned using water while drilling. You could use fast set while the hole is still damp. Not so with epoxy, it has to be bone dry (the kind I'm thinking of — A and B mix. Simpson makes a good one in a tube.). There are epoxy modified setting compounds but I'm not all that familiar. For those you need a hole big enough to pour the mixture in.

While most SDS drills can rotate without hammer, SDS carbide bits have severely negative rake geometries, so they don't really remove material without hammering (at least from what I've seen). I think it's to keep the carbide from chipping when hammered on.

Multi-material carbide bits will have a 90 degree rake that work aggressively well without hammering. Cheap carbide bits that come included with tapcons and such also tend to work better for me on rotate-only than SDS bits. And again, a plain cordless hammer drill is noisy as hell, but may work better with these sort of carbide bits.

Totally agreed that Tapcon is a terrible choice here. Moonrise's comment about the 25% safety factor for Tapcons refers to overhead lifting loads with a single fastener. We've got two bolts holding and nothing's being lifted overhead, but you do still need some margin of safety. I'd be comfortable with 2x, rather than 4x, and the two 1/4" Tapcons were right on that 1x line of failure. I just brought them up as a worst case example to flesh out if we really did need big anchors here, and the truth is we don't, because the large plate takes a lot of the stress away.

Wet use of an abrasive bit works, but it has to be really wet. Bluestone is soft enough that a wet/dry bit may even work better dry. The thing about wet cutting is that a slurry of cut material tends to gum up and lubricate the bit, so you need a constant flow of water to clean out the cut and keep the grit cutting.

I've used Mr. Sticky's epoxy to seal up underwater leaks, but I'm not sure how appropriate it is for anchors (i.e. what it's creep properties are). Plain mild (60ksi) 1/4" all-thread has a tensile strength of 1900 lbs. Stainless (75ksi) would be a bit higher at 2375 lbs. If it were my house and I anchored a stud, I'd be using 1/4" stainless all-thread, and like you said, I'd drill through the stone, at least for the inner two. Probably not for the outer two though, as that's where you're most likely to break the end of the stone off.

And as for the size of the hole, I'd probably use a 1/4" bit. The deeper you go when drilling masonry, the more the hole widens, and it will be plenty big to drop in a 1/4" threaded rod and bed it in epoxy. Also, the smaller the hole, the less likely you are to break the stone.

 

[Walkers]

This makes no sense.

That is what I thought too.

 

[shinnen]

Gentlemen,
Please remember that you're talking to a complete amateur here. I have two rotary drill, one is very slow, one is adjustable. Most of the terms you use go right over my head.
At this point, I'm really interested in knowing if my approach wrt to the Parasleeve, or some version thereof, sounds doable?
To recap .... I'm planning on drilling 4 holes in the concrete, epoxying the assembled broken pieces to the concrete, re-drilling the holes in that assemblage (large enough to accomodate the Parasleeves), driving the Parasleeve down (or just epoxying it in), putting some sort of thin cushion between the cap and the railing post base, tightening it down (carefully) ...... Bob's your uncle.
What do you think of this plan, in general? If you think it might work, what changes would you make to what I'm suggesting, especially wrt the cushion material between the post base and the cap.
Thanks again,
..... john

 

[Zeke]

I had to look up 'Parsleeve" as I have never heard the term. Over my head too, except to say they look like a typical expanding anchor. I thought that was discussed as expanding and outward exertion of pressure is what will push the repair apart.

The way I see it is:

1. The railing people are clowns
2. The stone people won't help
3. The GJ is a discussion group with no skin in the game.
4. You don't know what to do exactly

Therefore, I think it's time to call in a 3rd party like a hardscape contractor, a general who has a good man, or a handyman who knows what he is doing. They do exist.

Furthermore, I have no idea what the objective of a "thin cushion" is or what the expectations are. If it's a moisture barrier, don't use anything that has 'cushion' properties. Use copper, asphalt paper, galvanized or plastic.

 

[shinnen]

Hi Zeke,
My sense, from the image I posted, is that it expands in the concrete.
You are certainly right about nos. 1 and 4.
Yes, I'm sure that there are people who know what to do; but my experience, these days,
is that contractors don't want to be bothered with fiddly little repair jobs. The stone company told me that I will probably have trouble finding someone that will even bother with replacing the step, should I decide to go that route. They want large jobs.
Well, the cushion would be a material that would allow me to tighten the bolts, without breaking the stone, yet again; something that is compressible yet firm, like lead or teflon, around 1/8" thick.
..... john

 

[shinnen]

Gentlemen,
Just to let you know that I have 'repaired' the step. I ended up bonding the many pieces together with JB Weld epoxy (the iron filled version). It seemed to be very strong. After that I re-drilled the holes, right though and into the concrete, bonded the repaired piece to the step; inserted anchors and bolted the whole thing down with a thin layer of rubber (about the thickness of a stair runner) between the cap and the post base. (I had to re-drill new holes in the the post base.) The whole thing feels very solid, with only a slight crack showing in the cap. If it survives the winter, I will consider painting, or some other means of tarting it up.
Thank you all for your help. Your expertise has been invaluable to me.
....... john

 

[Dan in Pasadena]

I’d have cleaned the matching parts very thoroughly and spread Liquid Nails Heavy Duty Construction Adhesive then weighted it down.

It’s incredible how strong that stuff is.