×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Partially Rotted Top Chords Repair Advice Sorted

Partially Rotted Top Chords Repair Advice Sorted

Partially Rotted Top Chords Repair Advice Sorted

(OP)
Last night I found another area of my house with severe rot damages.  From the look of it there must have been a roof leak and the top chords of the trusses were damaged by water.  It is also quite apparent the roof deck was replaced and while they had the roof opened up and accessible, why they did not attempt a better repair puzzled me.

First, here is a picture of where the serious of trusses are tied to the concrete exterior wall.  The top chords actually extends four feet beyond the wall.  The trusses are numbered 1, 2, 3, 4 from right to left.



This is a view of the trusses from another angle.



First let me provide an overall sketch.  Each of these trusses have varying degrees of damages.  The rot happens at the top chord where the trusses are attached to the wall.



Replacing them is impossible unless I remove the roof deck, all the tiles above it, as well as the T1-11 soffit panel below, and the three layers of fascia and header on the end.  Above all, the top chords are all held down by this very thick metal strap that is buried into the solid concrete tie beam.  For these reasons I would prefer to repair/patch/mend if possible.

Now I will show the rot from trusses 1 to 4.

* TRUSS 1 - OK

This one is on the far right.  It has no rot and appear to be in good shape.





* TRUSS 2 - BAD ROT

This one is rotted pretty bad.  As you can see a repair was done previously when the roof deck was opened.  The roof deck is new.  The back side of this piece of rotted 2x4 wood is sistered with a 2x6, extended all the way to the header at the end of the overhang.  It is not really tightly attached to the rotted member due to the thick metal strap in between.  The bottom 2/3 of the top chord seem solid as I examined it.









* TRUSS 3 - MINOR ROT

This one seem to be only slightly rotted on the top edge.  Not too bad and there has been no previous repair done.





* TRUSS 4 - HANGING BY A SHOE STRING ROT!

This one is really bad.  The rot is almost 50% of the top chord and extends from two feet back of the concrete wall all the way to three feet on the overhang.  Must of the top is "mushy" and badly damaged.









I am thinking some repair is needed for trusses 2, 3 and 4.

My current thinking is to use wood epoxy to fix the existing members.  Probably using Abatron products to first soak the rotted areas with penetrating hardener or consolidant, then use liquid epoxy thickened with saw dust to the consistency of toothpaste and pack in the rotted area tightly.  Once they cured I will then use triangular shaped plywood gussets covering the top chord to the bottom chord.

Any thoughts and comments?  Thanks in advance!

RE: Partially Rotted Top Chords Repair Advice Sorted

(OP)
I just noticed on the last truss #4, the previous repair actually had cut the hurricane strap on the top.  The original strap was supposed to come out of the tie beam, wraps over the top chord and goes back down to the tie team.  They had cut it at the top and nailed it to the new sistered 2x5.



In any case I plan to leave the existing sistered members alone, as they were nailed in from the top through the plywood deck, and there are some lateral nails to the old rotted members, however I doubt I want to try prying those off and risk further damaging the original wood members.

Therefore my fix would have to be applied to the front side of the rotted members.

RE: Partially Rotted Top Chords Repair Advice Sorted

Wood trusses are an engineered product. You should have an engineer, experienced with the design of them, review the trusses and design the repairs for them.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

RE: Partially Rotted Top Chords Repair Advice Sorted

in addition, by the time visable 'dry' rot is observed, significant properties may be compromised.

Dik

RE: Partially Rotted Top Chords Repair Advice Sorted

If you've sorted it, why ask for help now?

RE: Partially Rotted Top Chords Repair Advice Sorted

Definetly, Rube Goldberg construction and repairs.

RE: Partially Rotted Top Chords Repair Advice Sorted

(OP)
The repair you saw was done by previous owner.  I just now discovered it.

RE: Partially Rotted Top Chords Repair Advice Sorted

miamicuse....sistering is probably your only option short of removing sheathing. Use "L" clips to attach sheathing to sistered chords.

Also, are you sure there hasn't been some localized fire damage here?  One of your shots (Truss 2) looks more like fire damage than rot at that location...the others are clearly water damage.

RE: Partially Rotted Top Chords Repair Advice Sorted

(OP)
Ron, I am not sure.  I am just discovering all this.  I assumed it's water damages because the sheet rock I took down had water stains on it, and the plywood above these trusses look new.

RE: Partially Rotted Top Chords Repair Advice Sorted

You might be able to go back to the:

    1. Real Estate Agent
    2. Owner
    3. Building Inspector

and sue them for either not disclosing or doing a bad inspection.

Also - you may have a mold problem??

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources