Built up center beam and the mysteries of life

[mreynolds]

As I was pondering how I am going to complete my first floor decking for my new house I had some main beam questions. My main beam is made of 3, 2x10's nailed and glued together.

My first thought was, using standard dimensional lumber, how do I ensure this built up beam is straight while I put it all togther (50 foot long)? Are there any carpenter tricks here or do I need to eyeball it? :roll:
How important is it that the butt joints of this beam meet over a support column? I had no idea I needed to do this until I caught it in a construction detail in a framing book. :wink:
Finally, this is an assumption, so I need a check here. I have 8 inch beam pocket and 1 1/2 inch sill plate (for 9 1/2 inches total). When I drop the 2x10 built up beam it will only be 9 1/4 inches. I am assuming I have to shim the beam pockets to get the 1/4 inch, so my I-Joists will lie on the center beam. What is the best way to do this? :roll:
Thanks again!!!!

[Rich]

For your main beam straightness I would eyeball it while you're building it. Then when you go to place it put a stringline on it to get it closer to straight. There should be no true butt joints. The outside 2 2x10's should hit on a column of some sort and the center 2x10 should be spliced at mid-span.
To shim your beam up the 1/4" I would line the inside of the beam pocket with 30LB tar paper and then shim with 1/4" hardboard which is the closest thing to uncompressible material. One thing to check before getting too far along is how level is the top of your foundation? You may need to shim more or knock down some concrete to get it all the same.

[mreynolds]

Thanks for the advice. That makes sense. I will definetly check that last course. I am really excited because I just priced the difference between the I-joists and regular 2x10, $400-$600 more, and one piece construction on the floor joists. Pretty neat stuff.

[Rich]

I love I-joists. It's been shown to decrease the amount of labor involved in floor framing by a considerable amount.

[mreynolds]

The other good part is it seems like the APA is pushing their use, so to do this they have tons of resources out there. This website http://www.apawood.org/level_c.cfm?content=pub_joi_libmain provides a whole list of free articles on how to detail and hand these materials.

[Rich]

www.trusjoist.com also has manuals on sizing of their I-joists and microlam beams. Included in the manuals are all the specifications for cutting holes and how to frame just about any condition you can think of.