Wood plank torsion, plywood removal
Question No. 1
Robert,
We have a shade structure. The opening where it comes off the patio to the deck has a 4x4 that is 14 feet long, is twisted and there is sap coming out of it.
We asked the contractor about this and were told that this is normal for wood to do.
Are we OK with this or should we be concerned?
— Kim F.
Answer No. 1
Kim,
This is not a proper build. The twisting is called torsion and is due to the span of the beam being too long for its thickness. It is not strong enough to withstand the stresses of the loads at its size.
The rule of thumb for structure is 1 inch of height for every 1 foot of opening.
With a 14-foot span, you should have a structural beam that is 14 inches high by 4 inches by 14 feet.
It sounds like you hired someone without sufficient knowledge, and clearly, who didn’t pull permits. Had permits been pulled this would have never been allowed to be built as it was. The plan checker would have caught it immediately.
I have concerns about the remainder of your structure and its safety and integrity. If this was done, I am forced to ask what else may have been done incorrectly such as brackets and other techniques.
I highly recommend you get a qualified licensed and insured contractor to evaluate this, and perhaps go back to your contractor with new information, and work out getting this structure rebuilt properly for safety reasons.
Good luck to you.
— Robert
Question No. 2
Robert,
I recently had work done on my home. My wife told me that the contractor removed two sheets of plywood and, when he was putting the area back together, he used drywall. She asked him about it and he told her that due to the thickness being the same, this was acceptable.
Is this the case?
— Rafael M.
Answer No. 2
Rafael,
Absolutely not. This is a shear wall, which requires a specific nailing pattern. The field (center) is 8 inches and the perimeter is typically 4 inches on center, but the engineer will call this out.
Shear cannot be arbitrarily added or removed, as the entire structure was engineered with it existing, for its structural integrity.
When things like this get changed, the integrity lessens and, in events such as earthquakes like we have in Southern California, structures are more likely to twist and break apart if they aren’t built to the engineer’s standards.
Your contractor is lacking in either knowledge or integrity, either of which is concerning.
Be sure to get them back in to do proper repairs and be sure to oversee it.
As I always say, a licensed and insured contractor should always be used for such important projects.
Best of luck to you.
— Robert
Robert Lamoureux has more than 40 years of experience as a general contractor, with separate licenses in electrical and plumbing contracting. He owns IMS Construction Inc. in Valencia. His opinions are his own, not necessarily those of The Signal. Opinions expressed in this column are not meant to replace the recommendations of a qualified contractor after that contractor has made a thorough visual inspection. Email questions to Robert at robert@imsconstruction.com.