Need a book? Engineering books recommendations...
RE: History of conventional wood framing.[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>
- Subject: RE: History of conventional wood framing.
- From: "Dennis S. Wish PE" <wish(--nospam--at)cwia.com>
- Date: Sun, 28 Feb 1999 20:37:33 -0800
I have to agree with Don Carr in his response to conventional construction. I understand from past discussions with Don what his concerns are regarding Conventional framing. He is absolutely correct that Conventional framing complies to a prescriptive method in the building code (at least it does in the UBC). He is also right on the mark that you can not imply Conventional construction to be the same as poor quality construction. Where I do not agree with Don is his last statement that "the codes are conservative and frequently result in an overbuilt structure." If this were, in fact, true, the insurance industry would not have lost so much money to failures incurred in seismic, high wind and flood type damages. The building codes (with the exception of the Wood Conventional Framing section) represents the MINIMUM design standard from which to follow - not the conservative and frequently overdesigned methods. Conservatism is in the hands of the engineer hired by the client to use his professional judgement in the process of design. For example, a box system designed using plywood shear elements would allow an Rw of 8 to be used in the lateral analysis. However, few engineers in a high seismic zone would use an Rw greater than 6. This was evident in the threads that we had regarding this matter. The resounding reason why a professional engineer would use an Rw of 6 rather than 8 is the factor of safety against the unknown problems that arise in the field by POTENTIALLY poor quality construction. The chances of finding poor quality construction increases simply because we our clients award contracts to the lowest bidders. General contractors hirer sub-contractors based upon lowest bid rather than known ability in much of the work performed. The only time I have seen this to be different is in high-end custom homes. The problem here is one of perception. I am pleased that Don has taken an active interest in conventional framing issues on the SEAINT listservice. Don represents the National Association of Home Builders Research Center. NAHBRC has taken a position more supportive of the builders and with less intervention by professionals. The problems, as I had clearly stated to Don in my concerns with a private list of the NAHBRC for REACH (Residential Engineers and Architects Council on Housing) is that REACH is a closed list. The list requires a membership in REACH. The Mission statement of REACH is an admirable task but, in my opinion, is unreachable because it lacks the open honest debate across professional platforms that is required to make a truly responsible team of Architects, Engineers, Builders and Building officials. Finally, the truth is that we have not been able to find a middle ground - basically an understanding that could have been accomplished by REACH if they kept their list open to the professional public who have strong opinions and suggestions about residential construction. Because of this, building codes ARE starting to become more complicated and restrictive - but only because there is no attempt to seek a fair solution in the construction industry. Therefore, the public is the ones who pay for the lack of special education and certification of those who actually construct structural systems. Special education and certification systems seems to me to be the only reasonable solution to qualifying a framer's competency. We certify or license architects, engineers and inspectors - why not provide some assurance that the person who reads the plans and lifts the hammer understands how a structural system is suppose to work? Don, I hope you don't feel I am trying to attack you or REACH. I think that REACH is a truly great idea. However, I do not believe that it can achieve success without opening a dialog with engineers and architects who are not willing to pay for membership. What better proof that where you are not debating this issue - on a public/professional listservice, the SEAINT list. Sincerely, Dennis S. Wish PE -----Original Message----- From: Don Carr [mailto:dcarr(--nospam--at)nahbrc.org] Sent: Friday, February 26, 1999 8:15 AM To: seaint(--nospam--at)seaint.org Subject: Re: History of conventional wood framing. Reference History of concentional wood framing Mostly I just listen but Gary Wheeler's definition of conventional Framing forces me to jump in. Conventional framing, in my opinion, is perfectly legal and quite often quite appropriate, safe, durable, and totally in conformance with the applicable building code. Conventional merely implies that the construction is done in accordance with the prescriptive requirements of the residential building code. It does not even exclusively imply wood framing.When conventional construction is done, it is usually inspected for compliance with the applicable building code. Any construction can be done badly, even properly engineered designs. Any construction can be poorly inspected, even properly engineered designs. Bad framers and conventional construction are not the same thing. Poor quality construction and conventiona;l construction are also not the same thing. Let's not make conventional framing a bad thing. There are many areas outside of severe seismic and/or high wind areas where conventional framing is both legal and appropriate. Don't forget, the codes are conservative and frequently result in an overbuilt structure. Don Carr > "Conventional" as opposed to "Engineered" or specially-designed. > Conventional implies wood framing built by north american carpenters > using their "traditional" methods. 2x4 studs 16" on center, three > studs at each corner, stud walls with double top plate & single > bottom plate, 4' lap at plate splices, plate splices over studs > only, two 16 penny nails endnailed thru plate to each stud, 1x4 > let-in braces at each corner and say 25' apart, etc. Wood 2x > rafter and joists per the tables in the building code and toenailed > to the top plate. Vernacular construction. No special inspections. > No special plywood nailing patterns, no boundary nailing, no > collector ties or fancy seismic holdowns. The only bolts involved > are the 1/2" anchor bolts 6' on center holding the mudsill to the > foundation. No glulams or steel beams. No engineer or architect > involved usually, and carpenters can do whatever the owner doesn't > notice and the inspector okays. > > I guess we should not assume so much when we use the term > "conventional". > > > Gary M. Wheeler, AIA, Architect > American Architecture Service. Try our Portal at > http://home.att.net/~g.wheeler > > > > > -----Original Message----- > From: Rodrigo Lema <rodrigolema(--nospam--at)softhome.net> > To: seaint <seaint(--nospam--at)seaint.org> > Date: Thursday, February 25, 1999 9:22 PM > Subject: History of conventional wood framing. > > > > I hope you understand that, living in a country where wood is > not used > >as a structural material (at least not frequentrly and certainly not in > >framing), I'm not failiar with certain terms. > > I'd like to know what is conventional, I mean conventional as opposed to > >what? > > Thanks in advance. > > > > Rodrigo Lema. > > > > Donald L. Carr dcarr(--nospam--at)nahbrc.org NAHB Research Center, Inc. 400 Prince Georges Blvd. Upper Marlboro, MD 20774 301-249-4000 x575 http://www.nahbrc.org
- Re: History of conventional wood framing.
- From: Don Carr
- Re: History of conventional wood framing.
- Prev by Subject: Re: History of conventional wood framing.
- Next by Subject: HOT list for SEAOC Convention
- Previous by thread: Re: History of conventional wood framing.
- Next by thread: TPI