Sagging Exterior PSL Deck Beam 1

[XR250]

I have a project where a 10-year-old exterior 3 1/2x16 PSL beam is sagging. The beam spans 18’-8” and supports 10 foot span floor joists. The beam is measured to be sagging 11/16”. I calculated it should be sagging no more than 5/16” supporting dead load only using a modulus of 1.4E6 per Weyerhauser and including a long-term creep factor of 2. I do not know who actually manufactured this beam, however. I probed the beam and it does not appear to be rotten. As such, I assume it is pressure treated,
About 15 other beams in this townhouse community are sagging similarly.
The sagging echoes what I have seen in other exterior treated engineered beams and have heard anecdotally from other contractors.

I don’t want to be the guy to condemn this beam and then have all the other townhouse owners calling me about theirs. How would y’all proceed? I’m leaning towards doing nothing.

 

[Tomfh]

Yes, creep and deflection can vary, but in this case, the main issue has been missed by the wood rep: the beam is sagging because it’s starting to fall apart.

 

[Eng16080]

Based on the picture, that looks worse than non-PT lumber that I've seen exposed to weather. I've seen timbers after fires that look better. 3/4" deflection with presumably very little actual load is not good. I would have guessed that a non-PT beam had been used in error. I can't believe the supplier both confirmed that it's PT and concluded that this is acceptable. Will definitely never spec this shit.