Re: ECO FRIENDLY POLE BARN
Welcome to CBN.
Use your plans and work accordingly. Just remember the dimensions of your wood and adjust. It may be best if you went through the plans and changed all of the dimensions. To give yourself that feeling of comfort lay out a couple of pieces on the ground following the dimensions in the plan and then following the adjusted dimesions and you will see it isn't all that difficult.
Good luck to you and post a picture or two of your project.
Re: ECO FRIENDLY POLE BARN
As welding said, make sure you adjust any plans you use for the non-standard lumber dimensions. It's a lot easier to do it 2 or 3 times on paper. It's actually not as bad as it seems.
Main components are the columns (posts), headers and the roof. Girts need to match the width of the header material for a straight wall.
You just need to make sure that your critical dimensions account for the different dimensions. I.e. a 24 ft width barn means the outside of the wall is 24 ft from the outside of the other wall, so you subtract girt width (usually 1.5" for a 2x4) and 1/2 the post long dimension (usually 1/2 the length of a 4x6 or 6x6, .5x3.5 or .5x5.5) from the outside wall line to get the exact center of the post hole. You'll have to adjust the above based on the exact dimensions of your material.
What are you planning to use for the roof? Trusses are the typical choice today but they are usually built from standard lumber by companies. I don't imagine a truss company would mess with non-standard sized lumber. Unless you're planning to build your own, but that is not a good idea unless you're getting an extremely good deal on the lumber.
Also, the (columns) posts and skirt boards are usually pressure treated. In fact, may be required by code in your area. I'm assuming (maybe incorrectly) that your locally milled lumber won't be pressure treated, so that may be a problem.
What about your barn will make it "eco-friendly"? If it's the locally milled lumber, I'm not sure I understand. If you don't use pressure treated lumber, you will have to take steps to ensure they don't rot prematurely (if code allows it as I stated above).
I would not be afraid to build a barn from locally milled lumber if, in fact, it was cost effective. My experience is that if you go to several lumber supply houses (or even online) you can have them quote a complete barn package very reasonably.
ps,
welcome