Addition garage and shop build: column or no column?

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Hi all, loving this forum and learning a ton. Time to ask a question!

I'm designing an addition with garage and shop on the bottom floor, and bedrooms on the second floor. The second floor layout demands an extra-wide 2 car garage (27'). I'm using I-joists, I really want to run them right-to-left due to the number of mechanicals that run that direction. This requires a beam down the center of the garage.

Since it is supporting a full second story, the loads require a pretty good sized beam. I can use an 5x18" beam to make the full 20' span and that gives a beam deflection of L/534 which is .462".

I can also drop in a post in the center of the garage which would drop the beam to 3.5x9.5" and give a similar (but lower absolute) deflection of L/537 which is .235". This reduces the cost of the beam from about $1250 to $350 (plus the cost of a column).

I'll get an engineer to do my final load calcs, but I need to know what I actually want first. What do you think? Most people are usually asking how to get rid of columns, I'm asking if I'm going to hate my decision to add one. The extra overall width would leave a bit more room for car doors than a normal garage with columns. I guess another option is to add a full wall between the two, but I'm not sure I like that option any better.

Thanks
Evan

 

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Can't seem to attach a full resolution link, but here is an actual attachment.

 

[cdestuck]

Money wise, I’d spend the extra 900 bucks not to have a post. The 18” height is a good bit of drop thought. What would be the distance from the floor to the bottom of the beam. And can the beam be recessed up into the ceiling and your joints tied into it?

 

[nadogail]

!. Welcome to the Forum from Southwestern California.

2. Have you considered a steel beam? With the current value of scrap, repurposed steel might be attractive.

 

[johnnyradiant]

Not having the post would be worth every penny of the added expense if it were my project. I think you (truck driver?) and car passengers would be thanking you, as the designer, if they knew what they were missing (pun intended). Over the life of the building how much is $800ish really? I think the only reason you aren't in the position of asking how to get rid of the post is because you don't have it built yet. And the cost of designing without the post is going to be significantly less than re-designing afterwards. i-Joists come in many sizes. What would the next size up get you in cost versus ability to downsize your centre beam? Is there a cost benefit in shrinking your joist spacing to save on beam size? If it were me I don't even think I would be looking at the whole post - no post thing. To me that $1250 beam is part of the cost of the project. If you're paying to get it built look at areas where you do some of that paid out work to recoup your $800ish.

 

[tarmy]

That post will be in the way of about half of your projects...the other half will be removing the post.

No post.

 

[makemenuconfig]

Thanks all for the feedback, no post it is! (The wife agrees)

Upsizing the i-joists won't eliminate the beam, so I'll stick with a very beefy beam. A 18" drop from a 9' ceiling is acceptable to me. I don't want to make it a flush beam for the mechanicals that need to run across it.

Thanks for the suggestion to consider steel. I hadn't because I'm much more familiar framing with wood. But I will ask my engineer to consider that as an option.