DCA09-DEC-025
Issue: Brad Weatherholtz, Director of Technical
Sales, Florida Roofing Sheet Metal & Air Conditioning Contractors
Association, Inc. seeks a clarification regarding Section 611.7.1 of the 2007
Florida Building Code,
Question 1: Is a 0.131 diameter nail, minimum 2.25” long,
acceptable as an existing nail in lieu of the above referenced .141 diameters
when re-nailing roof decks as per the 2007 FBC, Existing Building Volume,
section 611.7.1 and associated sections.
Question 2: Is .141 a typographical error?
Background:
2007 FBC, Existing Building with 2009 Supplement:
611.7.1 Roof decking attachment
for site-built
single family residential structures. For site-built single family residential structures the fastening shall be in accordance with section
611.7.1.1 or 611.7.1.2 as appropriate for the existing construction. 8d nails
shall be a minimum of 0.141 inch in diameter and shall be a minimum of 2-1/4 inch
long to qualify for the provisions of this section for existing nails
regardless of head shape or head diameter.
Situation:
The FRSA members have recently
discovered that the 0.141 diameter nail referenced above is not readily
available and research shows special ordering would be required as stated by a
large majority of distributors that were contacted. The commonly stocked diameter nail is .131
when using ring shank, 2.25” length, round head fasteners. Additionally it was stated that .0141 diameter
nails would not work in a majority of pneumatic guns as well.
The Florida Roofing Sheet metal
and Air Conditioning Contractors Association, Inc is requesting clarification
on behalf of Advanced Roofing Service of Ft Myers regarding existing nail
diameter requirements as listed above in section 611.7.1 Advanced Roofing Services is in the process
of undertaking a roof covering replacement project in Ft Myers involving a
single family home.
2007
Chapter 35 Referenced Standards - National Design Specification (NDS) for Wood
Construction- with 2005 Supplement
CHAPTER 23
WOOD
2306.1 Allowable stress design. The structural analysis and construction of wood
elements in structures using allowable stress design shall be in accordance
with the following applicable standards:
NDS National Design
Specification for Wood Construction
2306.3 Wood diaphragms.
2306.3.1
Wood structural panel diaphragms.
Wood structural panel diaphragms are permitted to resist horizontal forces
using the allowable shear capacities set forth in Table 2306.3.1 or 2306.3.2.
The allowable shear capacities are permitted to be calculated by principles of
mechanics without limitations by using values for fastener strength in the
AF&PA NDS, structural design properties for wood structural panels based on
DOC PS-1 and DOC PS-2 or wood structural panel design properties given in the
APA Panel Design Specification (PDS).
Referenced standard
2005 AF&PA National Design Specification for
Wood Construction
Table L4 p. 167
Staff recommendation:
Question 1: Is a 0.131 diameter nail, minimum 2.25” long,
acceptable as an existing nail in lieu of the above referenced .141 diameters
when re-nailing roof decks as per the 2007 FBC, Existing Building Volume,
section 611.7.1 and associated sections.
Answer: Yes. It appears that there is an internal conflict
within Section 611.7.1 with regard to the specifications for an 8d nails. According to the National Design Specification
for Wood Construction “NDS”, which is adopted by reference in the FBC, Building
Volume “See Table L4 above”, the minimum diameter for an 8d common nail is
(.131”). There are no technical bases or
justification available from the national standard of practice for the (.141”)
specification. Therefore, it is evident
that the diameter for a standard 8d Common nail is “.131 inch” and not “.141
inch”.
Question 2: Is .141 a typographical error?
Answer: See
above.