----- Original Message -----
Sent: Wednesday, May 16, 2001 1:14
Subject: Structural Adhesive
Here's the SHORT
We are looking for a structural adhesive
conforming to ASTM D2559 or D4689 for a field-constructed shear connection
from plywood-to-plywood or OSB-to-OSB (face-to-face).
Here's the LONG
Our firm performs many Lateral-Force-Resisting
System (LFRS) designs for single family residences in Washington and Oregon
States utilizing the 1997 UBC.
A standard detail that we include is a shear
transfer at the roof eave. This detail transfers roof diaphragm shears
to the shearwalls:
- Nailing through roof sheathing to bird
- Simpson A35 clips from the bird blocking to the
double top plate.
Occasionally (more often than we would
like) a contractor will ignore this detail. Upon inspection by the
local building official (always AFTER the roofing material has been
applied) it will be discovered that the nailing through the roof
sheathing to the bird blocking has not been completed, then we are contacted
for a 'fix'.
The two obvious options we come up
1.) Remove the roofing and add the nails,
the replace the roofing. This can be very expensive and time consuming,
especially if the roofing is tile.
2.) Provide the contractor or owner with a
Obviously the client never wants to tear the
We would like to provide a retrofit detail to our
clients for this shear transfer. The retrofit detail utilizes a
structural adhesive rather than nails to transfer the shear from the roof
diaphragm to a retrofitted wood assembly as follows:
- Roof sheathing, typically 1/2" CDX, to
sheathing between trusses/rafters, say 1/2" x 6" x 22 1/2"
CDX, via structural adhesive (set in place with wood screws)
- Sheathing between trusses/rafters to 2x blocking
via nail (assembled prior to glue application)
- 2x blocking to bird blocking via pneumatic
- Bird blocking to double top with Simpson A35
In the past we have specified a 3M
adhesive,ScotchGrip 5230, which is no longer available. According to the
APA technical note Number Y391C Structural Adhesives for Plywood-Lumber
Assemblies, we are looking for a glue that would meet ASTM D4689
Standard Specification for Adhesive, Casein-Type or ASTM D2559
Standard Specification for Adhesives for Structural Laminated Wood
Products for Use Under Exterior (Wet Use) Exposure
Does anyone have any recommendations of a
structural adhesive that would meet either of these ASTM specs?
Jeffrey T. Flansburg, EIT
John W. Parkin
500 Washington St.
Vancouver, WA 98660
694-8378 ext. 104
(360) 694-3376 fax