12
Technical BulleTin 2 – auGuST 2008
Notes
*
:
1 Unlled concrete block cells can create a reservoir that can hold water following a ood, which can make the blocks difficult or
impossible to clean if the oodwaters are contaminated.
2 Borate preservative-treated wood meets the NFIP requirements for ood damge-resistantce; however, the borate can leach out
of the wood if the material is continuously exposed to standing or moving water.
3 Not recommended in areas subject to salt-water ooding.
4 Examples of decay-resistant lumber include heart wood of redwood, cedar, and black locust. Refer to Section 2302 of the
International Building Code
®
(IBC
®
) and Section R202 of the International Residential Code
®
(IRC
®
) for guidance.
5 Using normally specied suspended ooring (i.e., above-grade) adhesives, including sulte liquor (lignin or "linoleum paste"),
rubber/asphaltic dispersions, or "alcohol" type resinous adhesives (culmar, oleoresin).
6 Examples include epoxy-polyamide adhesives or latex-hydraulic cement.
*
In addition to the requirements of TB 2 for ood damage resistance, building materials must also comply with any additional
requirements of applicable building codes. For example, for wood products such as solid 2x4s and plywood, applicable building
code requirements typically include protection against decay and termites and will specify use of preservative-treated or decay-
resistant wood for certain applications. Applications that require preservative-treated or decay-resistant species include wood in
contact with the ground, wood exposed to weather, wood on exterior foundation walls, or wood members close to the exposed
ground. In some cases, applicable building code requirements (such as those in ASCE 24-05 and IRC 2006) do not reect
updated guidance in TB 2 and specify that all wood used below the design ood elevation be preservative-treated or naturally
decay-resistant regardless of proximity to ground or exposure to weather. (Revision made in October 2010)
Fasteners and Connectors
The term “fasteners” typically refers to nails, screws, bolts,
and anchors. The term “connectors” typically refers to man-
ufactured devices used to connect two or more building
components. Joist hangers, post bases, hurricane ties and
clips, and mud-sill anchors are examples of connectors. Fas-
teners and connectors are materials and thus must be made of
flood damage-resistant materials in order to comply with the
NFIP requirements.
Table 2 does not specifically address fasteners and connectors.
However, it is clear that the performance of buildings that are
exposed to flooding is, at least in part, a function of the fas-
teners and connectors used to put the components together.
When preservative-treated woods are used, particular attention is required for fasteners and
connectors because some treatments are more corrosive than others, which could shorten the
service life of the fasteners and connectors. For example, alkaline copper quaternary (ACQ)
treatments are more corrosive than traditional acid copper chromate (ACC) treatments. If
corrosion occurs, buildings are less likely to withstand flood loads and other loads. Fasten-
ers and connectors made of stainless steel, hot-dipped zinc-coated galvanized steel, silicon
bronze, or copper are recommended for use with preservative-treated wood.
This Technical Bulletin, consistent with ASCE 24 and the International Code Series, recom-
mends that stainless steel or hot-dip galvanized fasteners and connectors be used below the
BFE in both inland (noncorrosive) and coastal (corrosive) areas. In coastal environments
where airborne salts contribute to corrosion, it is recommended that corrosion-resistant fas-
teners and connectors be used throughout the building where they may be exposed. For
Specications for fasten-
ers and connectors used in
buildings in SFHAs are in
ASCE 24, a standard refer-
enced by the IBC. Chapter
23 of the IBC has specic
requirements for connec-
tions and fasteners used
with wood, including pre-
servative-treated wood.
Similar specications are in
Chapter 3 of the IRC.