Need a book? Engineering books recommendations...

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


[Subject Prev][Subject Next][Thread Prev][Thread Next]


For that depth, you will need a backer rod, which is placed in the joint first and provides a “foundation” for the joint sealant to be poured against. I have copied a typical spec for the backer material:


1.1              General:  Provide joint-sealant backer materials that are nonstaining; are compatible with joint substrates, sealants, primers, and other joint fillers; and are approved for applications indicated by joint-sealant manufacturer based on field experience and laboratory testing.

1.2              Round Backer Rods for Cold- and Hot-Applied Sealants:  ASTM D 5249, Type 1, of diameter and density required to control sealant depth and prevent bottom-side adhesion of sealant.

1.3              Backer Strips for Cold- and Hot-Applied Sealants:  ASTM D 5249; Type 2; of thickness and width required to control sealant depth, prevent bottom-side adhesion of sealant, and fill remainder of joint opening under sealant.


Round Backer Rods for Cold-Applied Sealants:  ASTM D 5249, Type 3, of diameter and density required to control sealant depth and prevent bottom-side adhesion of sealant




Hope this helps,


Randall H. Collier, P.E.


From: Rich Lewis [mailto:seaint04(--nospam--at)]
Sent: Thursday, March 08, 2007 9:53 AM
To: seaint(--nospam--at)


I have a 12” thick slab on ground.  I’m wondering how deep the saw cut joints should be.  ACI 302.1R-04 “Guide to Concrete Floor & Slab Construction” does not have a recommended saw cut depth.  I have a 1989 version of the same standard where the recommended cut depth is 1/4 the slab thickness.  In this case the cut is 3” deep.  The joint then needs to be filled with a semi-rigid joint filler.  The tables I see for joint filler only go up to a joint depth of 1.75 inches.   Is anyone aware of other recommendations for shrinkage control joint depth for thick slab? 


Thanks for your help.


Rich made the following annotations
Attention: The information contained in this message and/or attachments is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any views, opinions, or thoughts expressed in this email reflect those of the sender, and do not necessarily express those of the company. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please contact the sender and delete the material from any system and destroy any copies. Thank you. ---------------------------------------------------------------------