Return to index: [Subject] [Thread] [Date] [Author]

Re: Structural Adhesive Wood-to-wood

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Jeff,
 
The 3M company recommends using their 3M5200 as a substitute for 3M5230.  Both are one-part synthetic elastomer based adhesives with very similar performance characteristics.  The 3M5200 was tested at 125% of the shear strength and 92% of the tnesile strength when compared to the old 3M5230.
 
Feel free to contact me if you need additional information.
 
Brian M. McMahon, E.I.T.
Universal Building Specialties, Inc.
Auburndale, Florida 33823
Phone (863) 967-1131 Eastern Standard Time
----- Original Message -----
Sent: Wednesday, May 16, 2001 4:14 PM
Subject: Structural Adhesive Wood-to-wood

Here's the SHORT story:
 
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 story:
 
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 blocking.
  • 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 with;
 
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 retrofit detail.
 
Obviously the client never wants to tear the roofing off.
 
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 nailing
  • Bird blocking to double top with Simpson A35 clips.
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 Conditions.
 
Does anyone have any recommendations of a structural adhesive that would meet either of these ASTM specs?
 
Jeffrey T. Flansburg, EIT
John W. Parkin Engineering
500 Washington St.
Vancouver, WA  98660
(360) 694-8378 ext. 104
(360) 694-3376 fax