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RE: H3LP REQUESTED: Paper on "Structural Design for Residential: A Comparative Study"

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Bill- I’m in Charleston, SC. We see a lot of residential design projects but most of the clients don’t want anything more than a foundation plan and wall section- the two magic elements of the drawings package, as they are the only ones required for permitting.  It’s extremely frustrating to deal with those clients because they don’t have any idea that to design the foundation we have to essentially design the entire house to bring all the loads down. Most houses here are on piles or piers so it’s important to know the point loads.

The other frustrating component- as in any structural design- is the architect. They produce their house plans with some generic sizes on some of the wall/building sections. Not nearly enough information to adequately construct the house. We are in a high seismic zone (D) as well as a high wind zone (130mph gust). Typically the wind controls for residential because of the light weight framing.

The real kicker is that there are engineer’s out there on their own who will produce foundation plans for $500 – how can that be worth the liability???  So we’ve started (trying) to “educate” our clients on the framing aspects. To tell them what they are getting from us if they have us do the entire framing package vs. someone who just pops out a foundation plan. We give them options- either they give us the loads to do the fndn design or we do the entire thing.

 

Jen

 

-----Original Message-----
From: Bill Polhemus [mailto:bill(--nospam--at)polhemus.cc]
Sent: Monday, July 26, 2004 10:33 AM
To: seaint(--nospam--at)seaint.org
Subject: H3LP REQUESTED: Paper on "Structural Design for Residential: A Comparative Study"

 

…or words to that effect. I just came up with the working title two seconds ago.

 

I’ve been thinking about this for some time. Perhaps the most valuable lessons I’ve gleaned from participation here on SEAINT is the insights into how residential structures are designed more “seriously” on the West Coast compared to here on the “Third Coast.” It’s intriguing to an even larger extent because I understand that for residential structures, and probably “light commercial” low-rise construction as well, wind tends to govern the lateral design.

 

Wind is something we have a heckuva lot of here on the Texas Gulf coast. Compare, if you will, the design wind speed for Southern California with that of those states bordering the Gulf of Mexico. I’m sure you see what I’ve getting at.

 

Yet we do not require structural design for residential construction here in Texas, owing mainly to the fact that we have no code enforcement except in municipalities, and counties are specifically prohibited from adopting building codes and enacting code enforcement requirements. This is a political situation entirely: The homebuilding industry here has convinced the legislature that to allow wholesale building code enforcement would make homes unaffordable to a large number of people.

 

I could present the political arguments pro and con, ad infinitum, but that’s not my object. My object, rather, is to compare the practices of structural design in, say, California, Oregon, Washington, Nevada and Arizona, say, with those of Texas, and ultimately, to show a glaring disparity.

 

Further studies could be made (perhaps “Part 2”, etc.) of comparative property damage costs that can be inferred to stem from this difference in approach. I have no axe to grind; I’m simply interested to know why we do (or don’t do) what we do (or don’t do) when it comes to structural design for residential construction.

 

What I’d like is some input from anyone who does structural design for residential, wherever you might be (I specifically mention the West coast but I wouldn’t confine my discussion to there). I’d appreciate this very much.