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Glulam Rot - Any Way to Remediate?

Glulam Rot - Any Way to Remediate?

Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

Normally, I'd suggest filling with epoxy, but that is pretty widespread rot and may be difficult and expensive to place so much epoxy.

RE: Glulam Rot - Any Way to Remediate?

Thats some anti-wood propaganda.

I would replace everything sketchy if I were the owner. And determine a cause for this.

RE: Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

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)


RE: Glulam Rot - Any Way to Remediate?

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.

RE: Glulam Rot - Any Way to Remediate?

Check out this recent thread. There's some great info from Brad about epoxies.

Link

RE: Glulam Rot - Any Way to Remediate?

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)


RE: Glulam Rot - Any Way to Remediate?

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 (www.strongtie.com), FYFE (www.fyfeco.com) and SIKA (www.usa.sika.com) have composite systems and epoxy systems for wood structures, but you case seems pretty extreme as far a extent, cost and practically.


RE: Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

(OP)
mike20793: thank you for the link

RE: Glulam Rot - Any Way to Remediate?

Can what is remaining handle the load after the beams are cleaned up?

Mike McCann, PE, SE (WA)


RE: Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

Looks like a rebuild to me. How old is the structure? How did the leakage get that bad without being rectified sooner?

RE: Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

Litigation potential? Insurance claim?

Mike McCann, PE, SE (WA)


RE: Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

Then YOU document it, not the contractor.

Mike McCann, PE, SE (WA)


RE: Glulam Rot - Any Way to Remediate?

(OP)
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.

RE: Glulam Rot - Any Way to Remediate?

Quote (CBSE)

how do you remove the rot?

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).

RE: Glulam Rot - Any Way to Remediate?

(OP)
Still getting pictures coming in....and it's getting worse.

The trusses that are bearing on the double top plate are rotten on the bottom chords as well.

RE: Glulam Rot - Any Way to Remediate?

(OP)
Ingenuity: Good ideas on removal. I was thinking along the lines of using hand planers...but that may take a while.

RE: Glulam Rot - Any Way to Remediate?

Quote (CBSE)

I was thinking along the lines of using hand planers...but that may take a while.

Planers work, but slow, as you stated.

Often the depth of damage varies substantially long the length of the beam, so a planer tends to remove to constant depth, taking out both good and bad wood.

We have found that a 5" electric grinder with wire wheels is very productive: daisy-wheel type for getting into local deeper pockets, and cup-type for larger flat surfaces. Also great for creating a rough bond texture if FRP is to be used for strengthening.

RE: Glulam Rot - Any Way to Remediate?

Take plenty of pictures and use your awl until it is a nubbin!

I was thinking a wire grinder of some sort.

If the remaining section is adequate, replacing the lost section may not be necessary.

Use a wood preservative in the areas where material was removed.

Mike McCann, PE, SE (WA)


RE: Glulam Rot - Any Way to Remediate?

If I were this owner, I would not want any of that rotted or repaired material to remain. But then some owners are not very scrupulous...

RE: Glulam Rot - Any Way to Remediate?

Quote (hokie66)

If I were this owner, I would not want any of that rotted or repaired material to remain.

Agree.

Quote (hokie66)

But then some owners are not very scrupulous...

Agree.

RE: Glulam Rot - Any Way to Remediate?

Best scenario Hokie, I would agree.

It will come down to what the insurance company will pay for and what the structural engineer recommends.

Mike McCann, PE, SE (WA)


RE: Glulam Rot - Any Way to Remediate?

It would depend on the conditions of the policy, but I believe most insurance companies would deny a claim for this degree of water damage, as the owner has taken no action to mitigate the damage over an extensive period. This even presupposes that water damage by failure of the envelope is covered at all.

RE: Glulam Rot - Any Way to Remediate?

True, but some policies have a provision for sudden failures regardless of any long term degredation. May not be the case here though...

Mike McCann, PE, SE (WA)


RE: Glulam Rot - Any Way to Remediate?

If you start taking off roof sheathing and trusses I suspect this is a rebuild. I would have suggested ultrasonic testing to map the degree of glulam rot, but this would seem largely pointless after looking at the pictures. The cost to engineer and implement a repair in this case is likely more or very close to the cost to replace. Do not underestimate your engineering time when looking at options. Each beam will be a unique design and when implementing the repair every time the contractor has a question they will want you to provide details or written clarifications (and I mean everything). I recommend you hire a contractor you like to prepare a repair estimate if required. This is not a case where we engineers shine at preparing estimates. We have fixed many glulams over the years for a variety of reasons.

When you go to site take a cordless grinder with a wire brush. A good cordless grinder will tell you a lot. I expect once you touch many of the areas with a grinder you will find a lot of more of the cross section will disappear very quickly. Rot is a lot like rust. Once you can see it you will find you have a lot more once you start repairing the problem.

A power planer works well to remove material if you intend to bond additional wood to the surface. It will leave a nice clean surface you can achieve a very good bond too and they can remove material quickly since they are 4" - 6" wide.

I trust you have figured out the aspect of the building envelope that failed.

RE: Glulam Rot - Any Way to Remediate?

I was called out to look at a house that had similar "simple water intrusion issues"... Three years, a giant report with 66 pages of pictures, and two days of depositions later, it was settled the week before I was to take the stand in court.

DOCUMENT EVERYTHING. Like Everything. Keep samples of whatever the contractor takes off the building, the beams you check, etc. Take a look at ASCE 11-99 (http://www.asce.org/templates/publications-book-de...), if you're in the States.

That looks like some serious water damage. I'd recommend shoring and sample testing at several locations. And yes, use that awl until there's none left!

Good luck.

Please remember: we're not all guys!

RE: Glulam Rot - Any Way to Remediate?

hey CBSE: the truss bearing pic you uploaded has a "&" in the title, and so I can't view it. Can you rename it to something simple, and reupload it?

Please remember: we're not all guys!

RE: Glulam Rot - Any Way to Remediate?

(OP)
Thank you for the recommendations! I'm flying, so packing a grinder and my awl will be cumbersome, and I don't particularly want to deal with the hassle. I will probably just buy an awl where I'm flying to and have the contractor supply a grinder.

RE: Glulam Rot - Any Way to Remediate?

(OP)
The more I see pictures, the more I'm thinking that this may be a complete loss. Who knows what the top chords of these trusses look like, and the rest of the plates, studs, etc.

The truss picture posted: obviously the bottom chord is gone at the bearing, and it looks like the top chord is probably compromised as well. The plate bearing below the truss is most likely a goner, as well as what looks like (or used to be) a simpson hurricane tie.

I will post pictures after my site visit. As I have said, I haven't dealt with rot before...fire damage yes, rot no. I will have a plethora of questions for the group.

RE: Glulam Rot - Any Way to Remediate?

OK UM.... did they cut the bottom chord, or has it sunk that much? And wow - the tie is gone, the top plate is gone, and what a mess.

Please remember: we're not all guys!

RE: Glulam Rot - Any Way to Remediate?

I've been involved with lots of dry-rot or more correctly brown rot projects.

Do a search on Eng-tips using 'dry-rot' and 'dik' as the handle. There are numerous hits with some excellent information from many posters.

Dik

RE: Glulam Rot - Any Way to Remediate?

Tear the building down and rebuild it. It is the prudent approach.

RE: Glulam Rot - Any Way to Remediate?

Was this one of those buildings clad with Dryvit fake stucco? If so, explains the rot!

RE: Glulam Rot - Any Way to Remediate?

We're not supposed to advertise, & I have no connection to these companies other than having used/seen their products on numerous projects so I don't think I am, but you should try Conserv Epoxy in Connecticut, Rotafix in the UK, & Rhinowood in Canada for solutions. I have done a pile of wood restoration in the past 35 years; this is bad but I have a couple of projects underway right at the moment that can compete with this for ugly. You're not going to fix these with epoxy alone but reinforcing strands (steel or FRP) and epoxy can do it if you really want to keep the building.

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