a BONUS PBG for Friday, May 31st — Column Spacing, Raised Floors, and a Self-Build
DEAR POLE BARN GURU: I have spoken to my architect and he is saying to do my column spacing 8′ with truss every 4′. I have looked at your videos and several other videos. I noticed 10′ or 12′ Columns with double truss is more than enough. This is going to be my house for now and later turn into my garage when my actual house it built. The size is 30x60x12. Also I will be using shingles for my roof since my HOA doesn’t allow metal. I am wanting to be efficient and save money but also have this built safely. ANGEL in SEALY
DEAR ANGEL: In our country, there are several places where post frame standard is just as your architect describes, however this is not necessarily most efficient for use of materials, structural sufficiency or ease of construction. We have provided roughly a hundred fully engineered post-frame buildings to our clients in Texas and I can assure you, columns every 12 feet with double trusses works admirably. While shingled roofs do not have longevity like steel roofing, we have clients who opt for this option.
DEAR POLE BARN GURU: I read your article about raised floors in post frame homes. I live in a flood prone area an was considering something like this. Do you have any other information or details? https://www.hansenpolebuildings.com/2018/03/raised-floors-post-frame-homes/ SEAN in PRAIRIEVILLE
DEAR SEAN: Thank you for your interest. One of our team members will be reaching out to you shortly, as we do need some very specific information in regards to your building site. This will include actual elevation of site, as well as your potential flood data.
DEAR POLE BARN GURU: Hey there! I’m wanting to self build a 50×70 or a 48×72 which is probably more cost savings. 16′ height and I’m leaning towards 10′ spacing. It’s a 3 sides equipment storage building. One of the 70′ sides being open. I need any help you can give on post spacing, 3ply or 4ply , truss spacing and a double header if I’m not locking into the post with the truss because the spacing won’t allow. I’m open to any suggestions. ERIK in SEYMOUR
DEAR ERIK: We do offer a 5% discount on buildings with multiples of 6′ in width and 12′ in length (read more here: https://www.hansenpolebuildings.com/2024/04/13-can-be-very-fortunate/). You will probably find columns every 12 feet on your open sidewall to be most ideal for equipment storage – as trying to maneuver even a full sized pickup or SUV through 9’8″ between posts can prove a good way to lose a mirror. Our typical engineered design is going to place trusses directly aligned with columns, so dealing with headers between columns becomes a non-issue. Your Hansen Pole Buildings’ Designer Cory will be working with you to make sure you get your best possible value for your investment.
In our system widths of 12’, 18’, 24’, 30’, 36’, 42’, 48’, 54’ and 60’ are most cost effective. For lengths, 24’, 36’, 48’, 60’, etc., providing building length is no greater than three times building width. Heights – even number multiples of two feet (10’, 12’, 14’, etc.).
DEAR RON: Lots of possible design solutions available. To begin with, I would recommend wood trusses – should you ever want to finish a ceiling, or if you want to have a product fabricated under strict quality control standards, then wood trusses are your best choice. On to options…. #1 My favorite. Make your building tall enough to have a full second floor. This will give you greatest usable space and best resale value. By using prefabricated wood floor trusses, you can still have a clearspan floor (no posts below) and it provides an unencumbered space below without columns to dodge. Yes, it will be a greater investment, but one you will probably never regret. #2 Prefab wood ‘bonus room’ trusses. With a steep enough slope (roughly 8/12) you can end up with an eight foot ceiling height at center and a room roughly 10-12 feet in width. For amount of space being gained, this is a fairly costly design solution. #3 Increase sidewall height and use scissor trusses to allow for a central mezzanine supported by columns. While likely to be your least expensive design solution, you will be faced with columns below (unless opting to again add in floor trusses.
DEAR ANNIE: As you get closest to square, your costs per square foot will decrease slightly. This is due to having less exterior wall surface, although it does not necessarily lend itself best to layout of rooms. For post frame construction, your most efficient use of materials typically comes from multiples of 12 feet in width and length. Work from inside out – do not try to fit your wants and needs within a pre-ordained box just because someone said using a “standard” size might be cheaper. Differences in dimensions from “standard” are pennies per square foot, not dollars. Post frame will always be your most cost effective structural design solution: 
DEAR JEFF: If erecting a roof only “pavilion” style post frame building, column dimensions are often dictated by L/d ratio as there is no wind load on totally open sidewalls. “L” is unsupported length of column (grade or top of concrete slab to bottom of truss connection), divided by least dimension of column. Playing a part in this is a factor known as Ke. Ke is determined by fixity of columns. On a roof only structure, columns act as cantilevers (think of a diving board), so Ke = 2.1. Looking at your 5-1/2″ square 6×6, 5.5″ x 50 / 2.1 = 130.95″ (or just under 10’11”). This means at an unsupported length of 11 feet, a 6×6 would fail. Obviously, truss span, spacing, and loads from dead, wind and any snow must be properly factored into equations to be verified by your building’s engineer. Adding an eave sidewall (or sidewalls) with open endwalls will cause bending forces to fail most 6×6 columns at lesser heights.
