Plans •
Brian Doyle, PhD P.E.
DOYLE ENGINEERING INC. M 5 -r 2, 0 � a _ I `I � Ep PROf
Special Projects in Combustion, 1� N .5: ; O
Air Pollution, Environmental and t ia �p1 �
NMI AIM ' General Engineering 17,427
REVISED "WC
NE Ellis Lane
Newberg, Oregon 97132 � V`3 —� m SOREGQi
503.538.2380 9,�, FiO T. 28, ,g9
doyleb @asme.org • K'EB SI ��
Brian W. Doyle
OFFICE COPY Oregon PE #17,427
30 July 2012
Ed Murphy
9875 SW Murdock
Tigard, OR 97224
re: Roof support for solar panels
When I did my original analysis, I was informed that the ceiling joists were 24" on center,
when they are actually 48" on center. So I re- evaluated the necessary reinforcement.
The new solar panels add less than 3 psf dead weight to the roof— which is quite small, but
the existing structure may not meet the current building code design requirements. The problem
is that rafter ties (2x12 ceiling joists) are 4' on center and the attachment between the rafters and
the joists may be weak. By adding nails or screws to this joint the roof will be strengthened
sufficient to bring the roof design up to current bui Id i ng code requirements. There should be a total
of 20 nails at each joint. Alternatively you could add 8 TimberLok, TrussLok or HeadLok screws
to each joint.
I will be available if there are additional questions.
end ofjiie
d�
. a.'� d
v�i� Existing 2x6 rafters @ 2' o.c.
- - - -
( Existing 2x12 Ceiling joists @ 4' o.c. NEREO PRUFEf
,,V 04 GINE .1%
/ 17,427 9 ,
Minimum of 20 nails (including existing nails) at each end
of ceiling joist. Add 16d nails as necessary
OR � ,ORE („e.
Minimum of 8 2%" HeadLok or 3%" TrussLok screws. �'�, F Ar 28. ® 0 ��
EBSTev
24' P 3
NOTES:
This drawing shows reinforcement of the existing roof to support
the small additional weight of solar PV panels. Existing tied rafters Solar Roof Supports
are 4' o.c. and original nailing is probably insufficient to meet
current code. Add nails as shown here will strengthen the roof Murphy residence
sufficiently to support the solar panels with a 25 psf snow load.
9875 SW Murdock, Tigard
scale: 1" = 2' 30 July 2012
DOYLE ENGINEERING INC 24001 NE Ellis Ln Newberg, OR 503 - 538 -2380 doyleb@asme.org