Ungrouted PEMB baseplates

[cec17]

I am reviewing some old projects and noticing where PEMB baseplates are called out with a note saying something like "Omit grout at PEMB baseplates". I am trying to remember why we did this, all I can remember is that it was directly requested by the contractor or PEMB supplier.

These are very lightly loaded, small PEMB columns. I don't see a load-related concern with omitting grout in this instance. Just wondering if anyone has info to the effect of why grout tends to be omitted at PEMB baseplates? Is there a technical reason (beyond cost savings)? Reading through Newman, it could be to more establish a pin base, or facilitate lateral slip. They don't say too much beyond "it's common practice".

TIA

 

[Aesur]

Grout would offset the foundation potentially affecting anchors (size and grade by the PEMB typically, embed by foundation designer) due to eccentricity, resulting in a field tolerance that isn't necessarily in their control. This would probably result in spending a few pennies more and PEMB's are designed to cut every bit of material out as possible. Additionally, these are also installed after the foundations are done, so maybe the trades are no longer even on site after the PEMB is installed. These are just a few ideas, however I agree, I have never seen one on a grout pad.

 

[JAE]

If you add grout - say 1" to 2" - all the PEMB door frames will be elevated off the floor - remember: the entire PEMB system works together and always ties into a theoretical base elevation of 100'.
If you raise the entire framing up an inch, you now have a gap to deal with.

This may also apply to their exterior metal siding which extends down to 100' as well.