Crack Wood Column Fix With Sikadur 1

[TomWaggoner]

Does anyone have any information on which if any Sikdur product can be used to fix cracks in a wood column? Am thinking inject cracks then full wrap with carbon wrapped epoxy. For reference the column is an 8x8.

 

[XR250]

Why not just sister with some 2x8's?

 

[oldestguy]

If that crack is not clear through, it is typical radial shrinkage starting at the tree center. No problem usually.

 

[TomWaggoner]

Actually headed out to look at the columns for the first time in a couple hours. In knowing the columns are 8x8's I can assume the roof spans are fairly long. I'm not sure if drilling a bunch of holes in the column to through bold it is something I would recommend. I'm also not crazy concerned about the cracks unless I see them around the connections.

 

[TomWaggoner]

Good info oldestguy!

 

[XR250]

I agree with odestguy. I doubt the shear demand is very high for a relatively straight column.
if you were going to sister for peach of mind, I would consider using nails - not bolts.

 

[epoxybot]

From the epoxy perspective, this isn't a good application. Almost any epoxy installed in that thickness would actually behave as a wedge and be destructive over time. The wood will expand & contract because of temperature, moisture or both, far more than most serviceable epoxies can accommodate. It is an error that has already been done elsewhere. If for some reason epoxy had to be used, it could only be done in concert with thru bolting to provide confinement to resist the wedge behavior of the epoxy.

This isn't a architectural application but if it were, using some of the methods seen with old masonry, malleable washers & wrought iron strap would be worth consideration.

If you have two splits directly opposed to one another, when combined, represent the full section, you need to do further evaluation.

 

[NorthCivil]

I never liked filling wood cracks with glue, just didnt sit right with my gut, epoxybot here has helped put some words to my feelings.

Whenever I get hit with a problem like this I always recommend to clamp the section back together and then fix with a few fully threaded ductile timber screws (myticon or similar). pre-drill the hole.

but looks like your situation isnt aesthetically nor dimensionally sensitive, so you may just as well sister a couple 2x8's and bolt through as XR250 has mentioned.

 

[hokie66]

I agree with through bolting, but don't see the need for sistering additional members unless you are trying to add capacity. Just bolts with washers each side should suffice to tie it together.

 

[TomWaggoner]

Went to the site yesterday and the radial cracking is on most of the columns. Always on just one side and never extending through to the other side. I'm thinking of using a 12ga plate instead of the 2x8's. I've attached a detail. Any thoughts on this?

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1533050993/tips/20180731_S1_Details_Review_um3xxt.pdf[/url]

 

[TehMightyEngineer]

Unless you're deficient on capacity I wouldn't do a thing. Wood posts generally have checks (splits); it's normal and trying to "correct" it could just make the problem worse or cause the other side to split. Grading agencies typically don't limit checking in the wood for grading, so it's considered normal in the design allowable stresses.

If it's for appearance I'd simply nail a veneer over it. If you need more capacity I'd avoid a steel plate like you show; it will resist expansion and shrinkage too much and possibly cause further issues.

Ian Riley, PE, SE
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/

 

[hokie66]

I agree with TME about doing nothing. Tom's proposed detail will accomplish nothing.

 

[epoxybot]

I think you will find, if you do a keyword search of Eng-Tips for "timber splits" that the consensus in other threads is to leave it alone. One concern is that, if the split represents the natural state of the dried timber, then the addition of any mechanical restraint will induce the timber to seek stress relief by another path.