Glulam Rot - Any Way to Remediate?

[CBSE]

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.

 

[CBSE]

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.

 

[CBSE]

Truss bearing picture.

 

[CBSE]

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

 

[Ingenuity]

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.

 

[msquared48]

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)

 

[hokie66]

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...

 

[Ingenuity]

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

Agree.

But then some owners are not very scrupulous...

Agree.

 

[msquared48]

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)

 

[hokie66]

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.

 

[msquared48]

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)

 

[Brad805]

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.

 

[SLTA]

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-detail.aspx?id=8068),

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!

 

[SLTA]

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!

 

[CBSE]

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.

 

[CBSE]

SLTA: Yes, try this one.

 

[CBSE]

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.

 

[SLTA]

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!

 

[dik]

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

 

[chicopee]

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

 

[Sawbux]

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