Builders Cottage beam question

[Shawn B]

I plan on building a 1 1/2 story 14' x 28' builders cottage with 12' sidewalls. The foundation will be 12" sonotubes with a approx 20" diameter x 6" thick footer spaced 7' apart. My floor joist will be 2x10 (for more insulation) and I want to have a 6" overhang, too make skirting the foundation easier/more attractive.

My question: Is the 1/2 plywood piece in the beam per the plans have any structural importance, or is it just a spacer? Can It be omitted?

The reason I ask, I was given several brackets that were custom fabricated with 1/4" plate steel. The problem, if it is one, the inside measurement is only 4.5", only enough for the 3 2x12.

I would like to use these because they are well made and the price (FREE) was right. But if these won't work I'll buy Simpson or a knockoff. 

Thanks,

Shawn

[Shawn B]

Well, after going back through several posts ( and years ) worth of questions I believe that the plywood is not needed and is just filler to accommodate dimensional lumber to fit the brackets.

Is 7' spacing of the sonotubes acceptable w/ the above mentioned platform design?

[John Raabe]

Yes, you can eliminate the plywood and the girder will have almost the same structural strength. Plywood helps weld the sections together and fill it out to fit dimensional lumber brackets. Make sure any joints in the 2x's fall over the piers.

You should be fine with your pier spacing.

[Shawn B]

Thanks for confirming that John. Just wanted to make sure my thinking is on the right track.


Now for the sonotubes, I'm planning on them at approx 18" above grade,  (My lot is almost level so they shouldn't very too much) to provide around 30" of clearance for installing DWV, insulating under the floor, etc.  Is there any issues with the piers at this height? I do plan to have the piers braced with treated 2x4's, then treated plywood over that for skirting. Then finish it with stone, rock, metal, etc.

[John Raabe]

With braced piers at that height it would take some outlandish forces to topple or twist your foundation.

That is not to say that there won't be a hurricane or tornado somewhere in the country in the next 50 years that could do the job.

Triangulating your bracing with a well nailed PT skirting will go a long way towards a lock on the foundation. Remember to also reinforce the connections at the floor to wall, and wall to roof if you are in an exposed wind environment.