Commercial girts sizing questions

[jumbinidaho]

I suspect this may be a really stupid question, so take it easy on me! I've decided to use commercial/bookshelf girts in an upcoming pole barn build. It looks like there are two main options - girts the depth of the columns, and upsizing the girts to stick out past the exterior column edge and then blocking on flat on the columns for an even plane between the girts and the grade board. The questions I have are:

1. I am planning on using 3 ply laminated 2x6 columns, which are listed as being 4.5" x 5.5" dimensions. With the narrow end facing the exterior, I have 5.5" wall depth. When upsizing the girts, everything i've read says "upsize to a 2x8 and stick the remaining 1.5" past the exterior edge". Now, a 2x8 is 7.5" wide, and my column is 5.5" deep. That's 2", so my girts would then be 1/2" proud of the on flat blocking on the columns. What am I missing here?

2. With the flush method, (2x6 the same depth as the column), it looks like I have to notch in the grade board. Are there any other issues that make the flush method inferior (other than 1.5" less depth for insulation)? I am planning on insulating and finishing the interior walls, but it's not going to be a constantly conditioned home, just a relatively small shop (750sq ft). 2x6 depth for insulation seems more than adequate for a smaller shop build no (I also plan on using house wrap and possibly 1" spray to seal it up pretty well)? Or is it worth the relatively low cost (would be a few hundred extra) to upsize, not have to notch the gradeboard, and gain the r-value (I am in a quite cold, long winter area)?

3. The other option seems to be to run the girts flush, and then run 2x4 on side on the exterior. It seems to be a highly opted for option in the commercial girt builds I can find examples of - is there a reason for this? Seems like adding a bunch more material just to avoid notching in the grade board? Is this just a remnant from when lumber was cheap that it was quicker to just run an extra layer around the whole thing?

 

[Daveyclimber]

Man, just do the girts flush, no need to over complicate. Some 2x8's can range from 7-1/4, 7-3/8 or 7-1/2. If you are thinking of doing this due to lack of insulation, consider using foam board or spray foam for better values. Both are far superior to fiberglass and stone wool Imo.

 

[dfiler2]

We used to set the grade board even with the top of the concrete so it wasn't an issue. Then you could toenail the bottom board in or use another girt on the outside that would give you what you want on the inside.

 

[racecougar]

I'm not following what you mean by notching the grade board.

I stuck with 2x6's for my commerical/bookshelf girts, which made insulating and sheeting a breeze. R-19 in the walls and ~R-55 worth of blown fiberglass in the ceiling has worked out very well here in MO. The building is quite efficient.