Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Why more Sheathing than in Zone 4???????

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Title: Message
I don't think we are comparing apples to apples. I understand that the additional cost of plywood is a consideration, but the point I am attempting to make is that while the developer benefits, the owner pays the price as performance is much lower on a home in California where the developer wants only the minimum sheathing to satisfy code and will not tolerate additional plywood. The other areas in the US, while not requiring as much plywood, provide it on new homes.
Sure, it costs more (marginally), but a home is dynamic. Its value changes and in most cases a new community constructed of lower income homes will become a community catering to up-scale middle class and will sell the same low income home at whatever the market will bear. This means that the new homeowners have proportionally higher out-of-pocket expenses to cover their deductible. The same home (roughly 1,500 square feet with a 400 square-foot garage) sold for $90,000.00 three years ago on a 50'x100' lot. Today, the same home is selling for $225,000.00 because of a new high-end gated community at the bottom of our hill (cove). The original owner, based on revised assessments will pay more than 15% ($13,500.00 to $33,750.00).
My complaint is that the engineering profession who is committed to protecting the public against death and "major structural damage" has backed down from efforts to work with the National Association of Home Builders and the Building Industry Association (both of whom have had enough of what they consider over designed engineered homes). The more conservative the engineering community attacks lateral loads for light-framing, the more incentive developers have to simplify their design to conform to conventional construction provisions (97 UBC 2320 or International Residential Code). In a high risk area, we are developing incentives to make homes perform worse than they had in the past and essentially bankrupting both the homeowner and the state run earthquake insurance fund.
Finally, engineers lose credibility with the public until it is too late. Trying to educate the public on residential construction is as useless as trying to explain the difference between Civil Engineers who practice structural engineering and Structural Engineers. I heard an ad on the radio today for the AIA - promoting hiring licensed Architects for your project. Why isn't the engineering community promote the same advertisement to attempt to lead the public into asking if the home is designed by an engineer or by simplified prescriptive methods?
We have  a long way to go before the public understands what we do for a living - for crying out loud, my parents don't even understand what I do for a living 20 years after I went into private practice (my dad passed away two years ago and he only understood a small portion of my work).
Sorry for the diatribe, but I hope you better understand why I believe that more care should be taken in higher risk zones to improve performance - something that is being done throughout the United States except where it really matters.
-----Original Message-----
From: Schwan, Martin K. [mailto:SchwanMK(--nospam--at)]
Sent: Saturday, September 27, 2003 3:46 PM
To: 'seaint(--nospam--at)'
Subject: RE: Why more Sheathing than in Zone 4???????

Dennis, I think the answer is it would cost more.  Labor: any one can pound nails but not everyone can lay bricks.  Time: a good crew can frame and sheath a house in less than two weeks; it may take more than twice that for masonry block. 


-----Original Message-----
From: Dennis Wish [mailto:dennis.wish(--nospam--at)]
Sent: Saturday, September 27, 2003 2:33 PM
To: seaint(--nospam--at); light_framing(--nospam--at)
Subject: Why more Sheathing than in Zone 4???????


I have just made my third cross-country drive from Southern California to Chicago since 1999. In my travels I look at construction in other areas and only in the highest risk area of Southern California do I find plywood or OSB sheathing used miserly. It is not uncommon to find entire homes - from the very basic to the most advanced, completely sheathed in Plywood or OSB including areas in low risk zones such as Oklahoma, Colorado, Iowa, Kansas and Missouri (west of the New Madrid Fault). So why are we in Southern California playing with fire. We have the highest average cost for a residential home and with a 15% deductible for Earthquake coverage, we will have the highest out-of-pocket expense to repair of all areas.

My cousin, who was a former Architect in California, moved to Charleston South Carolina and was on his way home when Isabel hit the coast of Georgia with the perimeter meeting South Carolina. When I contacted him, I found that his apartment, located on a small island west of Charleston, was constructed of masonry block and suffered no damage or property loss. I was also pleased at the performance of homes in area hardest hit which learned from Hurricane Andrew the importance of hurricane clips.

My question still remains - why, in an area of highest risk for earthquakes, do we allow homes to be designed so flexibly - either by engineering controlled by the desire of the developer or by conventional construction means - when we know that these homes - the majority of residential structures built and occupied by those who can least afford the deductible - will suffer more damage than we have seen in Northridge or Loma Prieta if all things are equal and more if the San Andreas moves with greater force.

I don't see the codes helping, except to drive developers to lower standards.


I heard the words from Gandhi" First they ignore you, then they laugh at you, next they become angered by you and finally change is brought about". Is the professional community still ignoring me or am I only a laughing stock?


Dennis S. Wish, PE