Best shim/block for support beam?

[cholland]

What's the best material for shimming up a support beam in the foundation?

I'm placing a built-up beam, made of 3 - 2x8s down center of foundation. It's a perimeter wall with beam pockets and 5 piers spaced down the center.  The beam pockets are about 1 1/4" - 1 1/2" deeper than than needed. I was planning to block in the pocket with PT wood, maybe plane it down a bit if needed to let beam sit level with mud sill.
The piers have Simpson PB6 post bases set in them. I'll be using 1/2" ply gussets at each connection to fill I the space. I will also stagger any needed splices in the 2x8s. The post bases vary slightly and sit between 7/8" - 1 3/8" low.

I planned on using PT 2x6 blocks, planed to fit the gaps and level the center beam. I pulled a string yesterday and started taking some measurements. Then began thinking about other types of material that might prove to be a better shim. Or something even easier to get the right spacing.
I've read about different shim/block material, including hardwood, steel and high strength plastic. The beam pockets need PT or steel to give at least 1" space for the beam because it is not treated. The pier brackets already have 1" steel spacers built in, so any material should be okay.

Softwoods like a PT 2x6 may compress? Steel plates would need to be galvanized and maybe welded. I would need to have to get them cut, etc. since my welding buddy moved to Idaho. Oak hardwood? Redwood? Plywood?

I also read about using high strength plastic blocks. Used mostly for precast concrete stuff but seems like it would be great for wood too. Varying thicknesses can be stacked and glued together to make the perfect spacer.

Anyone have experience with the plastic shims/spacers? Recommendations for best material to use in this case?
I've got a PT2x6 ready to plane down for what I need but thinking I might look for some of those high strength plastic spacers.

[Squirl]

Every book and contractor I had ever talked to used PT wood for the beam pocket.  2x pt wood is used for the perimeter of the rest of the sill plate.  It was the exact pieces I had to cut out from the sill plate.

I placed the pt sill and  j-bolts in wet mortar.  I used a level and a 2x8 cut end so that I could measure and keep the beam level with the upper sill plate.



Passed code inspection.

[Don_P]

typically planed wood is sufficient... if we're worried about crushing a wood shim then we should be equally worried about crushing the bearing point on the beam. i've used steel but like to put a piece of tarpaper or something along those lines between the wood and steel to prevent condensation problems from affecting the wood. UHMW plastic is fine. Basically anthing with a compressive strength higher than about 350 psi should do it. technically you should know the compression load in the bearing seat and check it against the allowable compressive load of the beam material and its' bearing area.

For wood blocks I like to find roughly quartersawn grain in a dense piece. Remember in a masonry beam pocket to allow air around the ends and sides of the girder, don't mud a wood beam in solid. It is not required to anchor bolt the shim, doesn't hurt anything, the perimeter walls carry the lateral.

[Squirl]

BTW, I know 1/2 ply is the standard spacer many use to reach x6 size.  I went with a 1x8 board.
It matched the x6 size.
I didn't have to do any ripping of plywood.
Albeit small, I got the extra strength of a 1x board in there.
I had a little extra to nail the floor joists into.
I didn't have to worry about any of the warpage or delamination issues with plywood till I got my floor on.

It is not a big difference, but it adds a little strength and saved me a lot of effort.  I just thought I would pass it along.

Also make sure the splices in the beam are over a post.  It is a common error that people post.