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I had a new roof replaced recently and my whole house would shake when they would throw the shingle bundles down on my roof. I went to the attic the next day and noticed something I hadn't previously. 2 of my roof rafters had a split in the wood. The split is length wise extends the entire length of the beam.

I showed this to my roofer and he laughed and said it was "checking". He tells me there is no way that his guys could have done this.

So a couple questions: 1.) Is this really checking or could the roofer have caused the damage? 2.) How big of a deal is this? Do I need to get it fixed? 3.) How do I fix it? Or more likely, who do I call? A general contractor? Another roofer?

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    OT - if that circuit is live you should terminate it in a box. – CactusCake Jun 30 '17 at 14:27
  • Even if it isn't live now, box it or strip it back... you never know what someone will do in the future. – Aloysius Defenestrate Jul 1 '17 at 15:44
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That crack is not checking. It's called "double bending" resulting in "horizontal shear failure".

Truss chords do not react to loads like joists do. Trusses are designed with each chord in tension OR compression, but NOT both. When the roofers dropped the bundles of shingles, (or worse, when they stacked the shingles in a concentrated area,) they put the chord in double bending. That is to say, they made the top chord bend. When this happened, the top half of the chord is put in compression and the bottom half is put in tension. This action increases the allowable compression and causes "horizontal shear failure"...tearing the wood fibers horizontally along the length of the wood chord.

Now, just because the chord has failed in horizontal shear, doesn't mean the truss has failed...especially because it is being held in line by the plywood nailing. The key to the TRUSS failure will depend on how the crack ends. That is to say, does the crack end in the middle of the chord, or does it veer off to one side (top or bottom) of the chord BEFORE it reaches the end of the chord. If so, you have a major problem.

I'd suggest you contact a STRUCTURAL engineer (not a CIVIL engineer) and have him review it.

So, I'm curious. Does the crack end in the middle of the chord or not? If not, does it veer up or down?

  • If I tell a roofer to instruct his crew not to drop bundles of shingles on the roof and not to concentrate them in one spot, will this be seen as offensive meddling? Will they adhere to my requirements in this matter? I have a truss roof (2x4s double-Fink on 24" centers) and the decking is less than 1/2" plywood (3/8"?). The roof is springy. Should I tell the roofer to add to the price if necessary? I have had two roofs put on in the 39 years we have lived in our 47-year-old tract house. Under the roof 2500 sq ft incl attach garage. Straight gable 3-in-12 pitch. – Jim Stewart Jun 30 '17 at 14:30
  • Hmmm...I think some roofers are more susceptible to constructive criticism than others. I've done a lot of inspections in my career and I think discussions about your concerns seems appropriate before start of work. I usually start with a question to the foreman, "How do you handle loading the roof, dropping bundles, etc.?" They seem more likely to remind the crew. By the way, where I live, 5/8" plywood is minimum required for structural (span from truss to truss) and for shingle manufacturer's guaranty. Are you sure it's 3/8"? – Lee Sam Jun 30 '17 at 14:45
  • Our house in Dallas, Texas is a Fox and Jacobs tract house built in 1970. The roof decking is the thinnest allowed by code for 24" O.C. trusses. I think it is 3/8". I am virtually certain it is less than 1/2". – Jim Stewart Jun 30 '17 at 15:07
  • @JimStewart If you're doing a reroof, you might want to check with the roofing manufacturer's printed warranty. I think most require 5/8" to guaranty against "blow-off". If you're doing a tear-off, you could add another 3/8". Roofing guarantees are like tire guarantees. They're pro-rated. So, in 10 years on a 30 year roof, they pay 2/3 the ORIGINAL cost of the shingles (no labor) but the cost to do the work soars. Keep your home insurance paid...lol. – Lee Sam Jun 30 '17 at 16:37
  • The crack in the wood terminates at both ends of the wood. It zig zags a bit, but generally stays in the top half of the joist. I can take pictures of the crack at the ends if it helps. – bMcNees Jun 30 '17 at 19:27
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Yes, checking is common and doesn't usually compromise the strength of a board. That crack appears new due to the bright color of the newly-exposed wood. However, I see no reason for concern, especially considering the robust solid wood deck you have, which effectively spreads load to adjacent rafters.

Now, any "professional" who laughs at your questions shouldn't be called upon again. You don't know whether other issues you may raise will also be dismissed with such rudeness. They also should not have been dropping bundles on your roof if only as a measure of respect. It certainly is unpleasant, and it dislodges dust and can crack drywall or plaster.

  • It's hard to see in the picture, but the crack is definitely a lot brighter than the surrounding wood. Nothing else in my attic is the color of the wood inside that crack. – bMcNees Jun 30 '17 at 19:28
  • I looked at the full size image and I think I may have misinterpreted what I saw initially. It could be a new crack as Lee Sam describes. – isherwood Jun 30 '17 at 19:42

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