Hello, I am new to this forum and hope to find some interaction and help here. Here is my project: My wife and I are going to be building a cordwood shop (with an upstairs apartment) this coming spring in Montana. I have a building and carpentry background, but have never built a structure this big before. The structure size is 35' long by 27' wide. The kicker is that we are striving to do this debt free. So, to me that means saving money wherever possible. However, I see no purpose in building an affordable structure if it means sacrificing safety or structural integrity. Here is a link to my plans below. https://www.dropbox.com/sh/shuqh8epf6dox18/AAASZoMgF0xjU-9_AsG0GuF-a?dl=0 I have most everything else figured out except for the beams I'll need. I will need 3 beams total.. (1) 26' & (1) 22' beams - equally dividing the length of the garage, & spanning the width. (1) 21' beam - upstairs vaulted ceiling running lengthwise from the right exterior wall to the center wall next to the bedrooms. My questions: What type(s) of beams are the most affordable / attainable without sacrificing structural integrity? What are the optimal dimensions and type(s) of wood that would be best for my application? Additional note: I am not opposed to using full logs. I also have an Alaskan saw mill, so I am able to mill whatever dimensions I need. Thanks everyone!

These beams are supporting the apartment above the garage? That's a lot of load without any kind of posts below to break it up. At any rate, you're into an engineered design. You might be able to get a lumberyard (a real one, not a big box store) to engineer the structure if you buy from them. I took my design to a lumber yard, and they spec'd the LVL beam and associated joists for our house. You don't say whether or not you are getting a permit or subject to inspections. Most inspectors are going to want some kind of proof that it is a safe design. In many areas you can't use your own lumber for structural use unless it is professionally graded and has a stamp on it.

If you can install posts next to the stair, you could use two cross beams of multiple LVLs (designed & spec'd by a full service lumber yard as jdebree says) with smaller joists which you could cut, attached or above. If you truly want no posts, redesign the plan so the stairs are straight and parallel to the floor joists. This will greatly simplify the beam & joist layout. If you really want to use your own lumber, you could probably cut large beams for all the floor joists, but sizing those beams to conform to structural standards is difficult.