# carbon fiber



## music9704 (Nov 4, 2009)

Opinions on carbon fiber. Sorry if this has been covered. I searched the forum. 
To make a long story short. I'm trying to figure out how to do some work my foundation. I'm just wondering about strength, cost. I was thinking of covering a crawl wall, 30" x 30' then parge.


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## sunkist (Apr 27, 2012)

My opinion on carbon fibre, Its a great product to build light weight panels in race cars and super cars, It also a light weight and strong materail for light polls and masts. But a real crappy foundation material and expensive, Carbon fibre panels get there strengh from multi layers.


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## The Coastal Craftsman (Jun 29, 2009)

*Carbon Fiber*

What were them carbon fiber reinforcement strips someone used on here a few years back. They didn't look strong enough but I guess it's still standing. Sure it's not a cheap option though. It's strong for sure but $$$$$


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## tgeb (Feb 9, 2006)

Here is one of the products.

http://www.fortressstabilization.com/index.php

I don't know how well these work. The weak link is the bond to the wall, if that fails the wall moves again.

My personal thought is that there are better ways to repair a cracked wall.


Worst case scenario, you install these and a few years later, the wall fails anyway and you fix it correctly at that point.


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## The Coastal Craftsman (Jun 29, 2009)

tgeb said:


> Here is one of the products.
> 
> http://www.fortressstabilization.com/index.php
> 
> ...



As long as that surface is cleaned up correctly I would say that bond would never fail. I would have a guess at the block cracking under compression before the carbon fiber and adhesive failed. Some of these resins they use on CF are crazy strong. Same exact stuff aircraft wings are glued together with.


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## dom-mas (Nov 26, 2011)

BCConstruction said:


> As long as that surface is cleaned up correctly I would say that bond would never fail. I would have a guess at the block cracking under compression before the carbon fiber and adhesive failed. Some of these resins they use on CF are crazy strong. Same exact stuff aircraft wings are glued together with.


 As to your other post it was greg???47k???? that posted about the carbon fibre strap fix on a foundation wall.

Concrete block will almost never fail in compression I can't imagine a case in residential or even most commercial (under 10 story say) construction that it would. Even 10 story...20 story...masonry doesn't fail in compression


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## Fouthgeneration (Jan 7, 2014)

Eng-tips.com has some carbon fibre threads (the Punster strikes!) under the structural engineering topics...

"sure wall" would be much easier to get, and probably cheaper...

Even stucco mesh embedded in plaster would repair all but the most heavily loaded crawl space wall panel. the mesh being mechanically fastened to the existing CMUs every 8" or less, and within 2" of the edges... 1 1/4" tapcons, screw driver head and an oversized washer or tin pan washer. cheap skates can use kinked galvinized 16p nail clipped short enough to drive into a 3/16" hammer drill bit hole(s).

One could even screw the mesh to the spread footing if needed....

power wash the existing block, acid wash if needed, the dryer the old block- the greater the bond. add little bonding agent to the first plaster coat.


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## The Coastal Craftsman (Jun 29, 2009)

dom-mas said:


> As to your other post it was greg???47k???? that posted about the carbon fibre strap fix on a foundation wall.
> 
> Concrete block will almost never fail in compression I can't imagine a case in residential or even most commercial (under 10 story say) construction that it would. Even 10 story...20 story...masonry doesn't fail in compression



Masonry certainly does fail under compression. Of course it takes a lot but my example is that carbon strap would fail far after the blocks would fail under compression. I'm talking about compression from the side where dirt is pushing the blocks inwards like they are imploding. The blocks would give out before the carbon failed.


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## music9704 (Nov 4, 2009)

Fouthgeneration said:


> Eng-tips.com has some carbon fibre threads (the Punster strikes!) under the structural engineering topics...
> 
> "sure wall" would be much easier to get, and probably cheaper...
> 
> ...


Sometimes its hard to tap this is old brick. The mortar joints are super soft. Bolting thru the mortar joint with washer on backside should work, correct. Just make sure to fill the joints good.


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## dom-mas (Nov 26, 2011)

BCConstruction said:


> Masonry certainly does fail under compression. Of course it takes a lot but my example is that carbon strap would fail far after the blocks would fail under compression. I'm talking about compression from the side where dirt is pushing the blocks inwards like they are imploding. The blocks would give out before the carbon failed.


That's not really compression, that's a lateral load...masonry performs terribly in that sense


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## The Coastal Craftsman (Jun 29, 2009)

dom-mas said:


> That's not really compression, that's a lateral load...masonry performs terribly in that sense



It will be compression on the rear because the front can't give because of the reinforcement in place.


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## dom-mas (Nov 26, 2011)

There is virtualy no instance that i can imagine that it would happen. Masonry can take incredible loads in compression. The joint may crack, a chip may fall off but the unit won't fail. Masonry often fails AFTER compression is relieved, but almost never fails in compression, certainly not in any residential circumstance


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## The Coastal Craftsman (Jun 29, 2009)

That's not my example though is it. I said that the block would fail under compression before the carbon would. My example is explaining how strong carbon is not how weak blocks are.


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## dom-mas (Nov 26, 2011)

I don't know...I'm sure carbon fibre is strong in tension, but masonry is almost limitlessly strong in compression


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## concretemasonry (Dec 1, 2006)

No question on the compressive strength of CMU walls. - How about a 22 story loadbearing apartment building built out of partially reinforced 6" CMUs with clear height of the walls of 9'-4". The maximum reinforcement on the lowest floor was one grouted core at 32" or 48" on center depending on which wall it was. Considering the concrete floor slabs and wall weights that is a lot of load on a 6" CMU wall. - A project of about 20 building built in Brazil using the same codes as the U.S. When I asked the engineer what code they used, he said "We use your codes, but we use them better" since masonry was faster and cheaper.

The grout and rebar do virtually nothing to increase the compressive strength of a wall, except in the case of very tall walls. The compressive strength of the mortar also has very little effect on on the compressive wall strength.


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## The Coastal Craftsman (Jun 29, 2009)

dom-mas said:


> I don't know...I'm sure carbon fibre is strong in tension, but masonry is almost limitlessly strong in compression



That's my point. The carbon will be under tension whilst the block compression but knowing a bit about carbon I would take a wild guess at it not failing before the wall. The block will fail before the carbon ever will.


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## superseal (Feb 4, 2009)

You're only talking four course of block and it's failing to the point of considering carbon fiber? Is it buckling in I suppose? or just general deterioration? What's going on?...

If indeed it's buckling in, I'd be more concerned with the reason for failure in the first place and then formulating a plan from there.

Sounds like you need some blockwork and drainage. 

Probably shouldn't comment till I know the facts...


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## Inner10 (Mar 12, 2009)

BCConstruction said:


> As long as that surface is cleaned up correctly I would say that bond would never fail. I would have a guess at the block cracking under compression before the carbon fiber and adhesive failed. Some of these resins they use on CF are crazy strong. Same exact stuff aircraft wings are glued together with.


Don't they use Redux for airplane wings? Maybe it's the same resin but the activator for the wings is a powder and it gets pressed together.


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## greg24k (May 19, 2007)

When you dealing with foundation wall being a block, brick or concrete, etc that foundation is intended to support compression load of the building. Carbon fiber is not intended to make any repairs which occur due to material failure from the compression load because of material failure or deterioration.

With that said, if you have a solid foundation, the tensile strength and lateral forces create the weak point in that foundation. Even when reinforcing materials being used like re-bar, dura-wall, etc to increase lateral load capacity of the wall, in some situations these methods are not enough and lateral forces will force the wall to move and create cracks, bowing out, etc. 

Carbon Fiber repairs will stabilize the foundation wall and prevent further movement. There is various types of repairs as there is various types of cracks and different situations which cause this cracks. If you don't have any training in identifying this situation, and don't know how to design a repair for each situation, don't waste your time and money, and call a certify installer to design and perform the repairs.

In addition, if you have a crumbling foundation, which is deteriorated and material's structural integrity is failing, carbon straps are useless and you have to explore other options to repair that foundation with carbon-fiber Kevlar cloth,Peel ply, or Nylon cloth etc, before using straps.

Other then that, Carbon fiber will not fail under any condition, they guaranteed for life and the wall will fail before the strap will if properly installed.

Here is a few images from 2 jobs of the repairs I did about 5 years ago, ran into one of the HO's a few months ago, there is not a hairline crack since I did the repair. Both houses situated in a high water table area with excessive hydro-static pressure. The owners always had water problems and as you can see both foundations cracked and bowed.


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## music9704 (Nov 4, 2009)

superseal said:


> You're only talking four course of block and it's failing to the point of considering carbon fiber? Is it buckling in I suppose? or just general deterioration? What's going on?...
> 
> If indeed it's buckling in, I'd be more concerned with the reason for failure in the first place and then formulating a plan from there.
> 
> ...


Thanks for info. Yes drainage was a problem (fixed). It needs re grouted.
OK here goes, 100yr old house. The foundation wall is all brick with brick columns.
I want to add more columns, so I was thinking I could remove a section of brick, and tie in a column using 4" structural block.
I'll pour a pier footer, and there's no backfill on wall. 
I know it probably should just have a new wall laid. I'm doing a lot of work with little cash.


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