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How Termite Damaged Truss Members Reinforcement

How Termite Damaged Truss Members Reinforcement

How Termite Damaged Truss Members Reinforcement

(OP)
All my roof trusses have heels that rest on and hurricane strapped to walls, except three of them.

These three trusses, on one end it's connected to the concrete exterior wall, on the other end they are fastened to a set of perpendicular double 2x10 beam by nailing into it's end.

This set of double 2x10 beam are then in turn connected (via joist hangers) to a double trusses on each side, those trusses ran further and sit on load bearing walls.

Here is an illustration.



The blue lines are the three trusses connected to the double 2x10, and the double 2x10 are then connected to the double trusses.  There was done back then to go frame around the chimney for the fireplace I suppose.  The chimney is big and is lined with at least 16" of concrete block wall where it's thinnest.

The problem:  The double 2x10 is damaged by termites.

Here is a picture of the what it looks like now.  I have annotated 1, 2, 3, 4 so you can correspond the picture to the illustration above.



Here is a close up of each annotated section.  You can clearly see what is happening after I "scrubbed" real hard the surface with a metal wire brush.









I cannot tell what's going on in between the two 2x10, May be no damages may be the same type of damages.

Here is a view on how the connection is made between the 2x10 and the double trusses, as well as the space between the 2x10 and the chimney wall.



I poked the 2x10 with a screw driver, and the deepest damage is about 1/2", but it is practically all over.

While I have the sheet rock down and have access to these, I am wondering if I should try to reinforce what has been damaged.

The double 2x10 appears to be still solid, but with the load it is getting from the three trusses, I am a little worried.

I can think of two ways.

(A) Attach thin plywood to cover the surface of the damaged 2x10, then inject liquid epoxy wood from the top and let the epoxy soak and penetrate all these tubes and cavities.  This does not address the surfaces between the 2x10 and the back side of the other 2x10 however, and I am not sure these liquid epoxy "flex" with the wood, it may not add any strength.

(B) Insert a new piece of lumber between the 2x10 and the concrete wall of the fireplace, attach that to the wall using Tapcon or concrete anchor, and attach the 2x10 to that.  However I am thinking there must be a reason they didn't directly attach the 2x10 to the fireplace in the first place.

Any thoughts?  Or this is nothing to worry about?

RE: How Termite Damaged Truss Members Reinforcement

The reason for the separation is for fire protection....common in older codes.

I would temporarily support the existing 3 trusses by fastening or actually "underslinging" an aluminum shoring beam from the double trusses, remove the damaged 2x10's and replace them.  Fairly simple process and requires no additional shoring.

The damage you see is likely not all.  Termites like to bore inside and often between two sandwiched pieces of wood.  I've seen them bore through the center of a laminated engineered wood bent in a church...showing no damage from the outside, but a hollow column section on the inside!

Epoxy can be injected in some wood applications, but I wouldn't suggest it here.

RE: How Termite Damaged Truss Members Reinforcement

I would replace all damage lumber. Also, paint any undamaged (and the replaced) lumber in the area with termite protection. Take a good look at the trusses to see if they have any damage. I assume that these are the air termites (same would apply to ground) so you should have the whole house look at and/or treated.

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: How Termite Damaged Truss Members Reinforcement

(OP)
Ron, you are absolutely right it is not that difficult to replace those two 2x10s.  I have been so fixated on mending, sistering, patching and didn't even stop for a second to think of total replacement.

One other solution I was thinking of, since this 2x10 is not this far off the concrete wall, only about 6 to 7 inches, I am wondering why not actually frame a wood studded wall using 2x8s right against the concrete wall.  I can erect studs where the three trusses sit and the load would be partially transferred to the concrete slab foundation.  I can build shelves inside this wall for stuff I need storage of anyways.

Then I can cut out the 2x10s, replace with new, the trusses would sit on the wall and be supported by the double trusses, I have extra storage space...would that be a good solution?

RE: How Termite Damaged Truss Members Reinforcement

(OP)
woodman88, these are not active termites but old damages,  The house was tented in 2007 and I believe no termites, it just so happened I opened up the sheetrock to make other repairs and saw this, decided to widen the opening to see the whole thing.

Sometimes it's best to not open ceilings and walls you never know what you might find that you don't really want to know.

RE: How Termite Damaged Truss Members Reinforcement

Obviously you are in a termite "zone".  Removal and replace is probably the best advice here.  I might suggest you use a small I-beam or C-Channel - no more termite problems and price is probably comparable.....

You might design and install a "flitch" plate - say 1/4'' x 9'' tall and bolted to existing header - if you feel the truss to header connection is still OK. Hard to tell from here???

Also - check the trusses - termites move around a lot!!

RE: How Termite Damaged Truss Members Reinforcement

(OP)
The double 2x10 beams, how should they be fastened together?

It looks like they are simply nailed together in a few spots.  Is the front 2x10 (the one the trusses are attached to directly) the one taking most of the load and transferring to the double trusses?

I think the way they did it, was they erected one 2x10, hung them on the double trusses with the joist hangers.  Then they applied nails through the back side of that 2x10 to connect to the trusses.  Then they hung the second 2x10 behind that, use joist hangers again to attach to the double trusses, and nailed to the first 2x10.

If I redo this wouldn't it be better to use not two sets of 2x hangers but actually one set of 4x hangers?

should I actually use structure glue (PL Premium) to glue the two 2x10 together so they are snug and tight?) and may be even a couple of 1/2" hex bolts.

What is the best way to connect the three trusses to the 2x10? Right now it is nailed straight through the first 2x10.  I am thinking joist hangers would be good but I can't nail to the face of these trusses as the truss plates are right there.

RE: How Termite Damaged Truss Members Reinforcement

miamicuse....you can still use joist buckets for the trusses after you replace the 2x10's. You can then strap the trusses to the 2x10's for uplift.

Under your building code, you cannot support the trusses on a free standing chimney. Further, any combustible framing has to be at least 2 inches away from the chimney.

Your choice is to support the trusses just as they are....but replace the 2x10's.

RE: How Termite Damaged Truss Members Reinforcement

(OP)
After looking at this a bit closer I see a few challenges.  The best approach is definitely to replace the double 2x10 headers.

I have several questions on how best to execute it.

(1) I am thinking the safest approach is to put a beam, may be a 4x6 or two 2x6 across the bottom of the three trusses and prop it up with several 2x4 columns to the exact current level.  However, whatever contraption that goes from concrete slab to these trusses will probably be in the way of me removing and erecting the new headers as space is tight and I need to fit two ladders in there for two people.  I am wondering, will it be sufficient to nail/screw a 4x4 beam to the double trusses on each end, to hold up the three trusses in between while I make the repair, or this is a bad idea?  I am thinking this is a bad idea.



(2) The joist hanger used to attach the 2x10 headers to the double trusses is a special item.  It is a deep one that reaches mounts the header to both the bottom and top chords.  I do not see in the Simpson's string tie catalog.  Anyone recognize this or can recommend an equivalent?  Here is a closer look.



(3) As you can see, the double 2x10 are very loosely connected, actually almost half an inch between them.  I wonder how much load the one on the left is really taking.  The three trusses are connected to the 2x10 on the right by nails, and these nails do NOT run through the 2x10 on the left.  I definitely see a problem applying nails from behind the 2x10 to the trusses, there is simply not enough room to swing a hammer or even a palm nailer.



(4) This one is really puzzling.  If you look closely at the connection of the three trusses to the header, the nails are being applied from behind the 2x10 and straight into the ends of the trusses.  However, due to the fact that the end of the trusses are truncated and the vertical member there are set back about an inch, these nails DO NOT reach the trusses.  Some of it missed the trusses and some of it barely touched.  You might think there must be nails up top or at the bottom to hold them together, I checked, NONE!  Is this a miracle or what?  It seems they are standing up there via pure friction!  Here are the three truss connections from left to right.






 

RE: How Termite Damaged Truss Members Reinforcement

miamicuse...go back to my 1st post...here's what I said..

Quote (Ron):

I would temporarily support the existing 3 trusses by fastening or actually "underslinging" an aluminum shoring beam from the double trusses, remove the damaged 2x10's and replace them.  Fairly simple process and requires no additional shoring.

This is exactly what is shown in your sketch on the photo and included in your question #1.  It will work, but you have to use a strong beam and U-bolts to undersling the beam spanning from double truss-to-double truss.  That's why I suggested using an aluminum shoring beam...it will work perfectly for this application and you will not compromise any clearances.

When you remove the damaged 2x10's, the new ones will be supported by joist hangers on the double trusses and you'll put joist hangers to catch the three trusses.  Check the Simpson Strongtie website for the proper hangers...they have a variety of them so pick one that fits your loading.

RE: How Termite Damaged Truss Members Reinforcement

(OP)
Thanks Ron.  Thanks for the suggestion that makes sense.  The only part I am a bit confused still is the use of U bolts.  I assume you mean using squared U bolts to fasten the beam to the double truss where the bolts would be applied "diagonally" and tightened with a cross piece and nuts?

RE: How Termite Damaged Truss Members Reinforcement

(OP)
I think this is what you mean?



I use a pair of U bolts for each connection and I need a steel plate right?

RE: How Termite Damaged Truss Members Reinforcement

You have more problems here then you can imagine.  Seek the help of a Structural Engineer well versed in roof trusses.

They are available all over the country.  Or I will fly in!!??

RE: How Termite Damaged Truss Members Reinforcement

miamicuse...exactly.  Sketch is correct.  For safety, I would also tie the top chords of the truss together to reduce the temporary point load on the bottom chord and not overstress any nearby truss plates.  You could also consider doing this at a couple of locations to spread the load on the double trusses.

RE: How Termite Damaged Truss Members Reinforcement

(OP)
MiketheEngineer, care to elaborate?

I am not changing the design or the configuration of the actual truss and header.  I am replacing a member with an identical piece, why would I need an engineer?

I am an engineer myself, just that I do highway and drainage and have not practiced in timber design but I do remember my structures classes LOL.

RE: How Termite Damaged Truss Members Reinforcement

One for one replacement is no problem.  I do see a problem with the attachment.  If you can resolve that - you are good to go!!

RE: How Termite Damaged Truss Members Reinforcement

(OP)
I assume you are referring to the pictures showing existing attachments where the nails do not reach deep into the ends of the trusses?

Those are the existing conditions.

When I replace the 2x10 headers I will redo the attachments.

Right now, my plan is to use properly rated deep joist hangers from Simpson's strong tie, plus end nailing, if I can get the nails applied with the limited space from behind - there may be enough room, if I predrill the front 2x10, and pound in 1.5" of the nails, then erect the 2x10 into position, I may be able to fit a palm nailer into the space to apply the nails.   Then I will erect the second 2x10 behind it, I probably will use PL Premium adhesive to glue the two 2x10 together, with several 1/2" hex bolts.

I am sure I can do better than what's there already.

RE: How Termite Damaged Truss Members Reinforcement

Yes - I was speaking about the connections.   But to be sure - just make a check on the beams you are replacing.  Sometimes - they weren't right to begin with...  Just a thought!!

RE: How Termite Damaged Truss Members Reinforcement

(OP)
I got all the parts for this, waiting for the big day to do this project next week.

Meanwhile, I found another spot I have rotted trusses.  The problem with living in Miami is rain and termites, they don't know how to stay away from trusses!

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