30A-014 (3) 30W old'
enalssance CORRESPONDENCE
Builders
P.O. Box 272,Turners Falls, MA 01376 Date of Transmittal: 04/04/2017
413-863-8316, fax 413-863-9712 Prepared By: Tricia Perham
Fax To:
TO City of Northampton PROJECT 2017012
212 Main Street
Northampton MA 01060 Lyman Deck Replacement
353 Florence Road
Florence MA 01062
Chuck,
Enclosed is the additonal information requested for the deck replacement project at 353 Florence Road. The
electronic copy has been emailed.
Thank you,
Tricia Perham
/ ( APR / °20.
/
/
.TECHNICAL BULLETIt -
M•� ' . .. SIMPSON
Installation Options for Deck Lateral Load Connections StrongTie
Background
When decks are supported by attachment to the primary structure,the International L° "
Residential Code`"(2000 through 2015 IRC)requires a positive attachment to that
building to resist lateral loads.These loads can result from wind or seismic forces ,i Band Joist
acting on a deck or from movements of the deck's occupants. If the hand joist, Floory
Sheathing e"9 g Deck Ledger
deck ledger or deck joists were to pull away from the primary structure as a result + nen"
of lateral forces,the deck would not be supported for gravity(vertical)loads and
would likely collapse(see Figure 1).
To help builders achieve proper attachment,an approved method was added to
the 2009 IRC to resist lateral loads by using holdown devices with a minimum
allowable load of 1,500 pounds in at least two locations per deck.The 1,500-pound •
holdowns connect a deck joist to a floor joist in the supporting structure that is . � } - }
nailed to the floor sheathing above(see Figure 2).The 2015 IRC now includes a Floor Deck Joist
second approved method that permits a holdown with an allowable load of 750 Joist
pounds in at least four locations per deck to fasten the deck joists to the top plate, Collapse lot
unsupported
studs or headers within the supporting structure using a fully threaded X"lag Deck
screw(see Figure 3).This new option allows a positive attachment for the deck that
is ideal when the house joists are inaccessible. $$$$ Figure 1
2Max. 7 . FIOOrL.. 5
Mar
si�nnr�reg ,}3%j4 tram End I.
I! -r,^e W It
s t ■
Deck
rt _,... The Simpson Strong-Tie®DTT1Z and
Loom 1 dg DTT2 deck tension ties have been
F u. DVS
wl u cost-e developed to Provide versatile and
Jori --r. = 3 a ' cost-effective solutions for these
r critical connections.The DTT1Z is
_ x= supplied with a ZMAX®coating;the
.,. .> J xSr`1• rYJ.>x ,1 DTT2 is available in ZMAX(DTT2Z)or
2111.1141717S44".1
` '-rstainless steel(DTT2SS)-
7111-1-49-14n1111-14.....-^ �,,��x ;+ '''Ff, :=--- - ' The DTT2 satisfies the 1,500-pound
----L J'="' requirement and is installed in pairs.
Figure 2(1,5011 lb.requirement) The DTT2 fastens to the wide face of
the deck and house joists with Strong-
Drives SOS Heavy-Duty Connector
Floor joists in supporting nmmore Equal screwsincluded , pair is
runt nnn.m mum be mmlplmgnpp PSIS Distances
screws(included),and the
anchored together with a Yi threaded
rod(washers included).
snppnnlnn b nom end r r me Fl,® r r mm e I The DTTIZ satisfies the 750-pound
motto( 1. e' L ; f.. requirement and fastens to the narrow
arts
L -=`� - _ — - �FLJ - or wide face of the deck lois(with
ons. I� �I to Strong-Drive SD Connector screws or
„tont
Dna a� nails and attaches to the supporting
roam `^' nang n0 structure with a fully threaded 2/8"lag
"' �"`" manv�r screw and washer(not included)or a
�— _E Strong-Drive SDWH Timber-Hex sWe screw with an integral washer.
JLL� s
Figure 3(750 lb.requiremem -
C2015 Simpson Strong Tie Company Inc.T-C-DECKLATI5 215 exp Se'
. ,. I°ns"dtr:xal7lfaop sins tofailick Lateral LoadC coons . ,;
h72 r mac. a�U . a .� < . 4G �7 a 144 %.
Allowable Loads
/dlo'nae tendon load pmtltsol •-.N
N",�-x, r k' ,v .FSSleado ; Of/SP 'SPFMF..-6WSPw 3PIAlf' ,
5-SD 09x1 w 840 840 840 755
DTP Z 1/4 or 6-10dx1Yi 910 i 640' 795 64O'
GDWH' 3-10dx1N 910 ' 850 910 850 1 7%. '—__3/4
1 OTT2Z/DTT2SS '8e 1x' 8-SOS'/4'x114' 1825 1800 1825 1 1615 T
1.Allowable loads have been increased 60%for shore-term loading with no further increase allowed.
2.Ory values are applicable to installations into wood with a moisture content that does not exceed 19%.
3.Wet values are applicable
e. allations unto Opd with a moisture content greater than l9%attime J� 4yiy
of installation or in service.Values include an NOSo wet service factor lotthefasteners.
4.MTV installations with allowable loads below 750 lbs.do not satisfy the 2015 IRC requirements for
deck-to-house lateral load connections. ,
5.OTTI Z installed with the Strong-Drive SOWN Timber-Hex HOG screw with a min.of 3'thread s
penetration achieves the lesser of the table load or 855WsSDW H installed with 3'of thread
p t r to dry lumber has an allowable ihd al load(IGO) f 1380 lbs to SP,1225 lbs. nto OFand lbs. nto SPE/HE D1T11
6 L d re valid I the productis flush th to nd of the fro q b r lnstallef away
from tM1 d. Ilsivie
�
1 FASTENERS-.SG e9xIH(model SO011210131 4 x 1W,10dxl1/20144 da-x 1W long. C4 4 F
.
DTT2Z
Conditions Not Shown in the IAC
The IRC details describe particular methods that are appoved and do not represent all common framing conditions.When
these are encountered,alternate methods of construction may need to be approved by the building official to ensure they
satisfy the intent of the code and are at least equivalent to the prescribed method.Several alternate construction methods
are shown here.
DT111 DTT1Z-750-Pound Assembly
- = Condition 1—Holdown Cannot Be Installed Flush
r " """ - with Wall Sheathing
E
'. 1?" Unlike some hoedowns,the DTT1Z seat is not =
• required to bear on sheathing or framing and can be nii
r installed away from the wall to account for non-
dm structural siding,g,foist hanger interference other
t re conditions.Longer screw anchors maybe required
- 10 ensure a minimum of 3"thread penetration by a re
-�4 ta4,5141214.: n. fully threaded lag screw or Strong-Drive°SDWH
fl"'"-----_ - Timber-Hex HDG screw into the wall framing.
--sY Dii12 Condition 2-Top of Wall Plate Does Not Align 21
Do not over-drive with Bonom of Deck Joest
anchoring screw
The 2015 IRC detail shows a hoedown installed on
Predrill%s diehole for fully threaded the bottom of the joist.However,the DTT1Z was
lag screw.Predrilling not required with tested and developed using 11/2'fasteners into
Strang-DriveeSDWH Timber-Hex HOG Screw. either the narrow edge or wide face of a 2x member,
(Siding not shown for clarity' allowing the DTT1Z to be installed at any location
along the depth of the joist.
Figure 4
2
.t Installation Options for3Deck Lateral Load tConnections, r' ',14
(house wall framing -- 24'
nm shown} en'Typ.Spacing OTT1Z—750-Pound A ,;ir,,,r.i ; • .)
tiro. 1W
Condition 8-Wall Plate Is
Joist Below Bottom of Deck Joi.
Extension
11,,4
Max.) wite h theIZ has hanbzen tstedl . L . shown in Figures 5A and 5B,
rw. ( which allows the holdown to
v (sSowngifnnot Mntyl V,'to Centerline be lowered up to 3%`below
or 0712 Anchor the bottom of the deck joist
6-Strong-Drives SOWS TIMBER Figure 5A Figure 5B in order to anchor into the
ScrewsiModei No SOWS2S0000B1 (side view) (end view) center of a wall plate.
2xex24'Blocking for Extensions up to iw
2x10x24'Blocking for Extensions up 10 33/4'
z3 Condition 4-Wall Stud Receiving MT LI
i —
, nstailotion orUecklatom( LoadC000rgons 5 _;
z % a „Si ,FYkz ..
•
DTT2—1,500-Pound Assembly
Condition 1-Floor Joist Framing Does Not
Line Up with the Deck Joist(Figure 9)
The D172 may be installed with a maximum allowable offset of 11/2" -=f, ORP btu floor Joists
when the ties are installed at(east 18"apart(see Figure 9).Larger ?d' eionlnt --
offsets may require an additional deck joist be added to line up with
the floor joist
ptu
Condition 2-Floor Joist Framing Is tIA'cme, r"'v0e0 m0 rare am
Perpendicular to the Deck Joist(Figure 10) wn4i"° Floor
Full-height blocking between Joists is a common constructiononP ' Band Jost Sheath
Band ost
a
method when lateral load is applied perpendicular to floor framing. , :The blocking for this application would have to extend into the -
--
floorframingfarenoughtopermit enough fasteners from the floor 1, I o
sheathing to transfer 1,500 pounds.An 8d common nail(0.131'X eck ed_� Ledger
r
21/2')through 751,2 wood structural-panel floor sheathing(6=0.50) omp oemtoiaiem
into SPF or better blocking(G>_0.42)has an allowable lateral design
value of 131 pounds(1.60 load duration factor').This installation om,oa,
would require 12 nails through the floor sheathing into the blocking. T
It is recommended that the blocking extend into the floor at least two
joist bays and the DTT2 be installed in the farthest blocked bay Figure 9 Figure 10
(see Figure 10).When nails into the floor sheathing cannot
be installed,see Condition 5 below.
'A load duration lector of l.60 corresponds to a 16minute da Fasteners Penmendecklme t
_..
duration of maximum load;adjust for other durations. 4`st supporting structure ex not shown For Canty
Condition 3-Floor Joist is a
Wood Truss or I-Joist
The DTT2 must be installed on a minimum 2x oaeeoam m
wood member.Some wood truss and lyoist
manufacturers have developed details to attach —
a horizontal 2x member to their product to 1
transfer a 1,500-pound lateral load Contact the -
manufacturer of the engineered floor component tin r •-.yg$
for more information. t AN)tun ter te e -
ncnoring and
Condition 4-Top of Deck Steps Down • taxma xamason
Below Top of Floor(Figure 11 and 12) xeanchor In
The DTT2 may be installed with as little as 4'of Figure 11 Figure 12
vertical overlap between the floor foist and deck
joist depths.Note that the code-prescribed connection between the deck ledger and band joist to support gravity
loads will require much more overlap When a step down results in a deck ledger that is attached lo a concrete
or grout-filled CMU foundation wall,the DTT2 may attach to a h'diameter anchor rod that is attached to the wall
(ledgers are not permitted to be supported by stone or masonry veneer).The anchorage and the wall should be
designed to support a 1,500-pound lateral load(see Figures 11 and 12).
Condition 5-No Access to the Top of the Floor Sheathing(Figure 13) SP
A
: 'ar
When the floor sheathing-to-Joist nailing specified in the IRC cannot be installed,an alternate connection
capable of transferring 1,500 pounds to the floor sheathing is required.Simpson Strong-Tie has evaluated 2.66..4%..
the A35 framing angle installed in K'minimum plywood or OSB sheathing with SPAR'M6 x 1/2'pan head %
full-thread screws.'The installation shown in Figure 13 has an allowable lateral load of 425 pounds per -.
A35(based on a 3.0 factor of safety).Use four A3S framing angles to meet the 1,500-pound requirement.
When fastened to full-height blocking(see Condition 2),use at least two A35 framing angles on each block. - - _.. ""m wuy'
'Available from Simpson Strongre in 200-count Poxes,Model Number SPAXX6xl/2'R200
Condition 6-No Access to Floor Joist Figure 13
When there is no access to the floor joists in the primary structure,the D717 750-pound assembly
(as shown in this technical bulletin)offers an easy-to-install solution.Where a positive connection to the
primary structure cannot be made or verified during inspection,the IAC requires the deck to be self-supporting.
'175'44?-1.):'
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