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Glulam Rot - Any Way to Remediate?

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CBSE

CBSE

Structural
Feb 5, 2014
309
US
Just got through providing details for a single story wood building modification. It is a complete removal of interior and exterior skin to the structural components. In the process, the contractor found extensive rot in this building. See attached images. The beams are all glulam beams. It appears the glue in the lamination's is probably almost all compromised.

I don't see any way to do a repair other than replace everything. Does anyone else have any less costly suggestions? The contractor is requesting a site visit, but I don't see the need based on the pictures.
 
 http://files.engineering.com/getfile.aspx?folder=a6e83bbc-0ca8-4634-9c59-20a12e58f6e2&file=Glulams.zip
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Normally, I'd suggest filling with epoxy, but that is pretty widespread rot and may be difficult and expensive to place so much epoxy.
 
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Thats some anti-wood propaganda.

I would replace everything sketchy if I were the owner. And determine a cause for this.
 
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Everything that caused the rot is being removed. It's a complete renovation.

Mike: What epoxy products would you use? I haven't had to do any rot repairs yet in my career...this is a first.
 
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I would beg to disagree here.

It does look bad, but if there is any chance of litigation here due to envelope breaches, I would conduct a site visit and document all the detail firsthand so you can talk to it - depth of deterioration, net remaining structural section, framing members deteriorated noted in a framing plan, etc, etc., etc.. You SHOULD write a report to address what you find too, with pictures.

Also, in the first picture, there looks like there is a joint in the framing at the left end of the edge glulam. What is holding it up?

Things like the above the contractor may not pick up. You physically need to be there. No Mr. nice guy on this one.

Mike McCann, PE, SE (WA)


 
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Any sense for the depth of penetration? With a fewer affected laminations, you might have been able to restore horizontal shear capacity with diagonally installed GRK screws or the like.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
 
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Check out this recent thread. There's some great info from Brad about epoxies.

Link
 
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I have considered epoxies in the past too, but you need to clean up the beams to see what good material is remaining to see if it is worth the effort.

Mike McCann, PE, SE (WA)


 
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We did a project about a decade ago to wood beams (not glulam) using epoxy paste resin and glass FRP to provide shear and flexural enhancement.

It was a historical structure and access around the elements enabled such a repair/strengthening.

Simpson Strong-Tie ( FYFE ( and SIKA ( have composite systems and epoxy systems for wood structures, but you case seems pretty extreme as far a extent, cost and practically.
 
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If the depth of rot is say, 1/4-1/2", how would you mitigate it? Shave it out and then do the epoxy solutions? The inside of the beams look good, but the outside is destroyed, or at least on the surface it looks destroyed.

mssquared48: I already sent a question to the contractor regarding the joint...I looked at it that picture and did the WTF double take.
 
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mike20793: thank you for the link
 
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Can what is remaining handle the load after the beams are cleaned up?

Mike McCann, PE, SE (WA)


 
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Not sure on that. I believe they are over-designed, based on experience of designing similar structures for this contractor. So, that being said, they can most likely handle the load if cleaned up. I just don't know how to clean the up. The remodel aspects I worked on were just adding some additional "skin" to exterior towers, it wasn't changing the actual structural system.
 
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Looks like a rebuild to me. How old is the structure? How did the leakage get that bad without being rectified sooner?
 
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The building is probably around 15-20 years old I'm guessing. I'm not entirely sure how the leakage went to this extent un-noticed. The contractor is completely removing the exterior. He wasn't going to remove the sheathing, but it looks like that will need to be replaced as well. I'm guessing it was just thrown up without much attention being paid to weather sealing.
 
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That's what I'm concerned about on my end with the extent of this.

I'm guessing the owner will want to do an insurance claim for damage.
 
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Then YOU document it, not the contractor.

Mike McCann, PE, SE (WA)


 
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msquared48: Yes. I'm arranging my flight to do a site visit. Back to the potential fixes, how do you remove the rot? I'm just not familiar with the process. I'm in construction as well, and I haven't dealt with this yet either.
 
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CBSE said:
how do you remove the rot?
Click to expand...

You have to be somewhat innovative, depending on the depth of rot and access to the work faces.

We used 5" electric grinders with wire-wheel attachments, small percussion-chipping tools, air-powered needle-guns, steel brushes, and all related items. Dry-vac up the cuttings, and then oil-free air blow with a needle point. Repeat as necessary.

Crude, but effective.

For glulam, if the laminations have separated, or the bond line has broken-down (assuming no rot to the subject laminations), it is possible to epoxy inject the laminations using traditional 2-components injection resin that are used for concrete repairs (i.e. injection ports, back seal, epoxy pump etc).
 
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