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April 27, 2007
The Editor
The Island Packet
P.O. Box 5727
Hilton Head Island, SC 29938

Re: Sun City Homes
Island Packet Article

April 22, 2007

I read with great interest the article in Sunday’s paper regarding the concern that has arisen with regard to possibly faulty roof truss connection in Sun City houses. As the structural engineer for Del Webb/Pulte, I would appreciate the opportunity to comment about several points the author put forth. Furthermore, as an engineer licensed to practice by the State of South Carolina, I have an obligation to public safety in general and the residents of Sun City that exceeds my client loyalty.

•  I am very satisfied that when properly made, a two-nail connection provides a holding capacity generally exceeding the loads that may result from a 130 mile-per-hour wind velocity, and when nails are missing or poorly installed, the remaining fasteners may be very adequate to securely attach the roof truss assembly without exceeding the accepted load capacity. I am also of the opinion that commonly made connections using nails have a load capacity that very much exceeds recommended design values.

•  The writer refers to a published diagram by indicating the two (2) types of connectors, nails and “H4” clips, be installed at each and alternate truss-to-truss crossing points respectfully [sic]. This is not at all the case. The diagram is indicating the use of nails at each such crossing point, or clips at alternate crossing points, not both.

•  Where both nails may be missing, installation of a single 10 gage by 3 ½ inch long screw at the connection restores load capacity, but I am of the opinion that even with imperfect installations, the homes are not likely to require this additional connector.

•  Concerning my comment regarding the need to inspect each house, I do not believe it necessary or appropriate. Considering what I believe to be the inherent strength of the installed truss assembly, I am of the opinion that there would be little gain by conducting detailed inspections.

•  The article referred to one homeowner’s concern about a tornado. A tornado has wind velocities greatly in excess of even the most powerful hurricane. Wood framed residential structures, no matter how well constructed could not survive tornado velocity winds.

•  The article continually refers to inspectors, contractors and homeowners expressing concern for faulty connections, but the number of missing connectors is never mentioned except the two examples cited by the reporter of 51 and 54 connections. Connections may indeed be missing or incorrectly placed, but the completed structure is likely to nevertheless safely withstand the stipulated 130 miles per hour hurricane wind velocity.

In all the forty years I have practiced structural engineering, rarely have I observed a perfectly constructed building, and undoubtedly a close inspection of virtually any residential structure will turn up various faults and defects of the type this letter attempts to address. It is my opinion that these homes in Sun City have been thoughtfully designed, constructed by a very well established residential homebuilder and the construction was inspected and found acceptable by the local building authorities prior to issuance of a Certificate of Occupancy. Compared to older homes using less sophisticated building materials and construction techniques, and likely having no inspections, these homes are very well constructed. These qualities, together with the inherent “robustness” of modern wood framed construction offers little reason, in my opinion, to be concerned about the safety of these homes.

Charles G. Thom, Jr., P.E.

South Carolina P.E. 13111

Material found at the community web portal. WWW editor  - Steve Koehl.  Revised: September 29, 2007.