Epoxy for Stone and Steel 1

[phamENG]

Anyone have any good recommendations for an epoxy that can bond steel to stone (assuming granite for now)? Existing lintel holding up face brick cracked during window install. Lead time for a replacement is prohibitive (original over 100 years old). I'm hoping to use the original stone and build a steel lintel to support it, but I need some nominal composite action. Sika says their anchor epoxy works with stone, but 1) they don't give values and 2) this is going to be more of a gluing a plate on shirt of thing. Anyone have a known product?

Not at my desk now, but I'll be doing some more research this evening...

Thanks everyone.

 

[dik]

I don't understand the condition. Can you post a quick sketch, or photo?

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[phamENG]

Sorry, dik - I was on my phone when I posted originally. Couldn't get a good photo, so I'll post a couple sketches:

So the ideal solution (minimal impact on schedule, doesn't require another trade - and a somewhat rare one at that) is what I have sketched in red. Strip the face brick from lintel to the sill above it and remove the lintel. I'm thinking some dowels and epoxy to mend the lintel itself and support it on a flat bar. Sadly a flat bar of appropriate thickness doesn't cut it - it wouldn't be stiff enough and the epoxy in the lintel would do all the work anyway. So I'm trying to come up with a product that I can use to feel good about composite action between the plate and the stone. Carbon fiber would probably be a better choice, but again that would require bringing in another trade. A steel angle would certainly work (these windows aren't large), but there's no room for upturned angle without modifying the stone, and that requires a stone mason if they don't want to risk damaging it even more.

This may be a terrible idea, so I figured I'd throw it at the wall here and see if it stuck - if anyone know of a good epoxy to make it stick. I'm not afraid to tell the contractor what needs to be done, but these guys go out of their way to try to make my job easier in most cases. So I'm trying to explore more...exotic options for their benefit.

 

[dik]

Can you sawcut it 1/4" or 3/8" and insert and 'glue' an HDG steel plate, on edge? Less visual... I've done that a few times. Is the sound part of the stone at the supports in good condition? How large is the span and is there adequate arching action over it. You have to be careful with epoxies and zinc. Your approach with the plate on the flat works, using the epoxy to secure the plate to the stone.

Can you use epoxy injection to 'patch' the crack? or stainless steel?

and, why did the stone lintel crack?

like:

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[IRstuff]

Since you're willing to have the lintel sit on a bar, can you have something L-shaped, where the vertical of the L is between the lintel and the wall? That should increase the apparent stiffness of the support for the lintel.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[phamENG]

They don't want to cut the stone - it seems to be in fair condition, but without an experienced stone mason they're concerned that they could do more harm than good. Drywall is already staged, and windows arrive in 2 weeks, so ordering a replacement stone to be cut or to cast a replica would eviscerate their schedule. They're just "fortunate" that they picked this one to do the mock-up and we can solve it before it's a critical path delay.

Span is only about 38", and there's a good 40" of brick over it to the underside of the sill (that unmarked, long rectangle on my sketch), so it'll arch.

What kind of epoxy did you use? If the zinc might create a problem, stainless could be considered.

 

[phamENG]

IRstuff - trying to avoid cutting the existing stone. If it's what it takes, it's what it takes, but I'm exploring other options first.

 

[dik]

or (The things at the end are pins):

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[Enable]

I've never used it but a job I recently bid included the addition of tensile reinforcement to the underside of an existing underground parking garage concrete slab in the form of steel plates epoxied / anchored. The epoxy they specified was: Sikadur 32 Hi-Mod Bonding agent

The location was in an exposed above grade parking garage. Assuming the engineer wasn't off his rocker it'll probably work for your location as well then. Give your local Sika-Rep a call to see if it would work for stone. I suspect it should as the datasheet says masonry is acceptable.

 

[dik]

I don't recall the epoxy, but it was by Master Bond (that I do remember)... they have 'glue' to stick anything to anything... You might check with their customer service; they were extremely helpful. I'll see if I can dig up the info... I still likely have it, but scattered among 40,000 files...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[phamENG]

Enable - thanks, I'll look into that one.

dik - I'll check them out as well. I thought about the pins, but I hadn't satisfied myself on how to go about it. If the bottom were hidden I'd just have them bolt it, but I'm not sure about welding pins to the plate, drilling holes in the stone, filling them with epoxy and spreading epoxy over the surface and then dropping the plate into place. Maybe it could work well enough...

 

[IRstuff]

I wasn't suggesting cutting the stone; just to use essentially angle iron on the bottom instead of a flat piece.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[Ingenuity]

ProPoxy 300 by Dayton Superior. 1:1 gel epoxy, that you would butter-up the plate and press-apply to the stone.
SikaDur 'family' of resins by SIKA. Same as Pro-Poxy essentially.
Kemko by Chemco Systems. They have a range of products of varying consistencies/set times.
Master Builders/BASF have similar products too.

When we used to do steel plate bonding (before mid 1990's, when FRP took over), we used to inject low-viscosity resin into inlet ports with sealed perimeter OR pre-apply gel epoxy to steel and press-apply to concrete. NEVER use galvanized steel for bond-critical applications.

 

[phamENG]

IRstuff - right, but cutting the stone would be required. My sloppy electronic penmanship did no favors - there's no gap between the stone and the brick behind. And if the angle were turned down it would be in the way of the window installation.

Thanks, Ingenuity. I've got a call in to Sika, and I told them I want to discuss FRP options, too. I've spec'd it for concrete but not stone. And thank you for the advice on procedure.

 

[dik]

Generally good advice... but, there are some epoxies that work. Two different issues... the bond of the HDG to the steel, and the chemical reaction of some adhesives and coating systems to zinc... I was thinking of the latter.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

 

[jayrod12]

Could the stone not just be reinstalled the 1/4" or 5/16" of the angle vertical leg thickness? Or is all of the face lines that tight on the brick? It would look intentional almost and solve a whole bunch of issues.

 

[XR250]

What about using a carbon fiber strip like those foundation companies use to reinforce basement walls?

 

[phamENG]

The more I've thought about it the more I like just using an angle, so I've asked the contractor to do a little more exploratory demo once they have some shoring/sidewalk protection in place. The back is tight to the brick and the face is a continuous band around the building, so something has to give to get it in there, but I think that'll be preferable to epoxy.

XR - I told the Sika rep I wanted to discuss that when he calls me back, so we'll see how it works with the stone. I imagine it's okay - there are stone basement walls out there - I just need to be sure it can be adequately concealed.

 

[kipfoot]

Not an answer to your original question, but a replacing the timber lintel may be a clean approach. As a bonus you get rid of one of your timber lintels.

In one of my projects, there are shallow masonry arches constructed over the timber lintel, which would simplify the lintel swap.

 

[phamENG]

kipfoot - I do like that idea. No arch on this one. The wood is doing the work for the inner wythes while the stone is carrying the face on the facade. So we'd have to needle beam the wall above...I'll have to see if the scaffolding they're putting up (hopefully put up) has enough capacity to double as shoring to support it...the timbers are in shockingly wonderful shape given the application, location, and age, so replacing them may be a tough sell.