Wonder what the preferred method of installing multiple 2x6 to create a support column is when the existing 1939 wall (bottom plate, studs, top plate) is 2x4 construction? These columns are to carry the load from girder trusses carrying the new SIP roof and attic trusses to the foundation.

I.e, may the 2x6s be installed parallel to the wall, so that two of them fit within the existing 2x4 cavity? Or is letting the 2x6 "overhang" the bottom/top plates OK other than making the wall thicker?

Per the engineer, (2) 2x6s may be replaced by (3) 2x4s, and (3) 2x6s by (4) 2x4s. But no replacing (4) 2x6s with 2x4s - must stay with 2x6 or 4x4x1/4" tubular steel post?

Thanks,

Rick Gregory

The preferred method would be the 4x4 steel post to keep your wall planes flat and avoid trimming a bump out in the wall. You wouldnt overhang the plates, a shim should be installed along with crush blocks below.

In some older homes with full 4 studs, lath, and other typical situations of the old home era, you could actually bury a 2x6 into an old 2x4 wall, for example an old exterior wall might be 3/4 board, full 4 stud, 3/4 board, 3/8 lath and 1/2 plaster. Thats 6 3/8", enough room for 7/16 ply, 2x6 stud, 3/8 gyp.

Thanks for the reply Greentree.

Not sure how a 4x4 steel column can fit in the existing wall without some 'fudging', since the column is really 4" not a nominal figure like 2x4. The actual wall is 1-1/16" lath & plaster, 3-1/2" 2x4 and 3/4" solid wood sheathing, for a total of 5-5/16". Per the engineer, the solid wood sheathing has to go, to be replaced with 4x8' OSB panels due to earthquake codes here on the Wasatch Fault.