Monday, June 29, 2015
A ROTTEN TRAGEDY IN BERKELEY
I assume everybody has seen in the news of the tragic accident that happened in Berkeley, where a balcony of an apartment building broke and fell to the ground killing six people. Indescribable tragedy, which I'm sure will be followed by lawsuits. But who is really to blame?
Preliminary reports say that the balcony, supported by the cantilevered floor joist, was designed properly. The code requires that balconies be designed for a "live load" supporting people, at 60 lbs./sq.ft. -- 50% more than floor loads of the same floor. Then what was the problem? Structural engineers visiting the site and looking at photographs said there were clear signs that the joists supporting the decks had rotted due to water exposure by the phenomena called "dry rot".
Dry rot is a condition of wood in which a fungus breaks down the wood fibers and renders the wood weak and brittle. Excess moisture is the root cause of dry rot. Dry rot is often confused with termite damage, because it is similar in appearance. Termite damage is, of course, visible by live termite galleries, termites swarming, termite droppings and it happens mostly in dry wood. In the case of balconies, the most likely scenario was that the waterproofing at or under the balcony door was insufficient, allowing moisture to penetrate this area and causing dry rot.
Is this avoidable? During my illustrious career I've been involved in numerous construction defect lawsuits -- mostly as an expert witness and not an engineer being sued. The majority of these lawsuits involved water leaking claims and damages caused by dry rot. Of course if a window is leaking and causing wood damage by dry rot, is not life threatening. It is a completely different situation with decks and balconies.
There were incidents in Santa Barbara and San Francisco before, where decks collapsed due to dry rot damage, injuring and killing people. Is there a way to avoid this? Yes and this is what I propose.
Everybody knows that if you build a flower bed you use pressure treated wood or "green wood" (not to be confused with the phrase "going green in construction" which is so popular these days). Pressure treating is a process that forces a preservative deep into wood products, preventing moisture from penetrating. These days there are no more "green wood" products, because the chemical used before is not "chromatid copper arsenate", but a less toxic borate based material. There are some other safer products as well. Arsenic is of course very toxic. (Do you remember the play by Joseph Kesselring, "Arsenic and Old Lace"?) Needless to say this process makes the wood quite unappetizing to all vermin, insects and fungus. So what am I saying with this? If pressure treated wood is more resistant to dry rot why not use it in construction in areas where it is more likely to get in contact with moisture? If Noah's Ark was made from this stuff, it would still be cruising the Mediterranean!
So, let's update the building code to use pressure treated wood products for all decks, bridges, balconies and similar areas, where potential damage by dry rot, termites, etc. can cause accidents injuring, or killing, people. It’s a safer, simpler, inexpensive way of construction!
Posted by Unknown at 1:25 PM