Tag Archives: wood trusses

A Wood Frame Basement, Inside Dimensions, and Steel vs Wood

This week the Pole Barn Guru about building a wood frame basement with “daylight space,” the inside dimensions of a 40′ x 80′ structure, and a debate between steel vs wood construction.

DEAR POLE BARN GURU: I’d like to build a post frame building with a daylight basement space. I’d been researching permanent wood foundations and thought I could likely do the same using the post frame method instead of stick building basement walls. If properly engineered and waterproofed according to the wood foundation folks, do you see any reason why this couldn’t or shouldn’t be done this way? The first-floor walls would be about 4 feet below grade except at the garage entry at grade. The site is level but the street slopes down to allow the grades to work out. In this condition would you use a shallow post footing or wet set a bracket? I like the idea of minimizing the concrete, especially the footings and stem walls of conventional stick framing. ROB in PORTLAND

DEAR ROB: We are actually going to be inventorying 2×6 and 2×8 #1 SYP treated to FDN requirements in just a few months – one reason being exactly for cases like yours. To minimize concrete required, once site has been graded to level, glulam columns would be embedded with a concrete bottom collar (roughly 18″ deep of concrete), with balance of hole backfilled with compactible fill to grade. Permanent wood foundation walls would then be placed between columns on top of gravel.


DEAR POLE BARN GURU: If I build a 40′ x 80′ pole barn as a home, what would the interior dimensions be? FRANK in STERLING

DEAR FRANK: When your new Hansen Pole Buildings’ barndominium is all framed up ready for interior finish, inside dimensions will be 39′ 0-1/2″ x 79′ 0-1/2″ assuming a single story and fairly typical climactic loads.


DEAR POLE BARN GURU: I am building a 30X50x14 Pole building. I am stuck on a couple things. Steel vs wood and thickness of the concrete. I will be putting in radiant heat and also plan of having an auto / truck lift in the building. Another reason I am thinking of steel is an overhead chain hoist. Thank you for your help and time. ROB in BEAVER FALLS

DEAR ROB: Steel vs. wood – if this is about how your building will be structurally framed, prefabricated wood roof trusses can be engineered to support any sort of concentrated load you may be considering – we just need to know in advance how much weight and where load will be picked up from (steel frame needs this information as well – just because it is steel, does not mean one can arbitrarily hang greater loads from it). In order to achieve greatest value for your heating dollars – wood trusses allow for you to have a ceiling you can insulate above, rather than having to heat air space far above where you actually need it to be comfortable. Concrete thickness – your lift provider can advise as to what thickness of concrete will be necessary to support their equipment. Keep in mind – slab only needs to be made thicker where lift will be positioned, so it isn’t like your will have to make entire floor thicker. You can easily ‘step’ your under slab insulation down where concrete needs to be thicker.



Dear Pole Barn Guru: Wood or Steel Trusses?

Welcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: Should I go with wood, or 12 or 14 gauge steel trusses? DELIBERATING DEE

DEAR DELIBERATING: I came from the prefabricated wood roof truss industry, having spent nearly two decades either having built them myself, been a designer, managing or owning roof truss manufacturing plants.

 In my experience I learned prefabricated wood trusses are amazing products. Not only can they be utilized for a myriad of different application, they also are a highly engineered product. Every component of a wood roof truss is put through a rigorous computer analysis, which verifies all members are capable (when properly installed and braced) to be able to withstand not only the snow loads to which they will be subjected, but also wind loads. The entire process is remarkably complex, involving the most up-to-date research available. Because of this, wood roof trusses just do not experience failures, within the parameters of the design loads.

 Besides all of this, pre-fabricated roof truss manufacturers are required, by the Building Codes, to be inspected quarterly by an independent firm for quality control. These inspections are done without any advance notice – the inspector just shows up unannounced. The truss company must supply the engineer sealed drawings for every truss the inspector wants to review. No engineering and the trusses must be destroyed. The inspectors are so thorough, they even take a micrometer to the steel roof truss plates, to confirm they are the correct thickness! The size and grade of every piece of wood in the truss is verified to meet or exceed what is specified on the drawings, and all of the joints between the wood members are checked to make sure they are tight. Even the placement of the steel plates must match what is shown on the drawings.

 The inspector also looks to make sure completed trusses are adequately stored to prevent deterioration of the wood members and to prevent damage to the truss plates.

 In other words, the inspections are rigorous.

 When I owned my first business, in Oregon, we hired a very nice gentleman to be a pole building sales person for us. Originally from Arkansas, Stan’s father built light gauge steel truss frames for “pole” buildings (in their case, the entire structural framework was made of steel, so they actually were not pole buildings – but rather light gauge steel frame buildings).

 Stan discussed with me his interest in building the same type of frames and distributing them in the Pacific Northwest. While I didn’t see this as a fit for our particular niche (we were pole buildings only), I did give Stan my blessings to head out on his own and start his own business.

 Apparently things were a little different where Stan was from – the steel truss frames there were made of steel angle iron for the top and bottom chords, and rebar was welded in between for the internal webbing. Engineering was never a requirement, Stan’s daddy just built them using seat-of-the pants – with the assumption if they worked in the past, then they would work in the future.

 The Pacific Northwest was not quite the same as Arkansas, as Stan quickly found out. In order to acquire building permits (required on most uildings in the West), Building Departments required engineer sealed drawings for the steel truss frames. Having to engineer the trusses resulted in upgrades to the designs – no more rebar for truss webs, they had to use angle iron there as well. Plus, it required certified welders having to do the fabrication. These requirements added exponentially to the cost of the frames, and made them have to play by rules similar to the prefabricated wood roof truss industry.

Stan long ago sold his interest in the company he founded, but it continues to fill a place in the market. The buildings are generally 15-20% more than post frame construction.

 As to the choice of trusses, most people are very comfortable working with wood as wood tends to be very forgiving. Attaching wood roof purlins to a steel framework is not as easy or straightforward as wood to wood.

 Part of the answer to your question is – what is it going to cost? In order to get a direct comparison, make sure the proposed light gauge steel trusses being quoted come with wet sealed (not photo copied) structural drawings. The drawings should also include the requirements for bracing. Steel trusses normally take diagonal steel struts from the bottom chord of the truss, up to the roof purlins, to prevent buckling of the trusses in the weak direction. The bracing, as well as any connectors should be included in the price. Detailed instructions should be provided so the trusses are adequately attached to the columns, and for installation of the bracing.

DEAR POLE BARN GURU: Do you have someone to install your buildings? TEXAS JEFF

DEAR TEXAS: Hansen Pole Buildings is a supplier of pole building kit packages only.

 You do not need to hire a contractor to build your pole building. Our buildings are designed for the do-it-yourself person. Most of our clients do their own construction. We believe our drawings and industry-leading Construction Guide are clear enough to make the task relatively simple, even for the first-time builder. Keep in mind this is a material kit, not a completely pre-fabricated structure. Assembly, including measuring and cutting, will be required. You will be required to have (or borrow or rent) various hand tools. If you are not comfortable with putting up your own building, a contractor should be available at a reasonable price. We have found the average person who can read and understand English can, and will, build a better building for him or herself than most contractors. Why? Because it’s YOUR building and you will take the time and care to do it “right”.                                                                                  

We are clearly not contractors in any sense of the word. We do not construct, build or repair buildings (or portions of buildings) anywhere for anyone. Should you need a builder, we DO have a list of builders for nearly anywhere in the country. Please call our office to receive a builder referral.

 Keep in mind, a referral is not an endorsement on Hansen Pole Buildings part of the particular builder’s skills or lack thereof, As none of them work directly for us, we can’t guarantee the quality of their work, We DO have a “one strike and you’re out” rule for our referral list. Simply, if we receive even one verifiable and legitimate negative complaint about any particular builder, we will no longer give out their name to our clients. While this is not a fail-safe method, it does afford some degree of protection, it is always a good idea to speak with other customers the builder has done work for in the past, to get an idea of the builder’s professionalism.



Pole Barn Truss Spacing

What do you mean they are not 2 feet apart?

Back in the day (early 1990’s) I was on the National Frame Builders Association (NFBA) Board of Directors. One of my fellow board members from the Midwest wanted to take a peek at how pole barns were constructed in the West, so I invited him out for a tour.

After spending a day looking at several of our building projects, his comment to me was, “The inspectors in our area would never let a pole building be constructed with roof trusses placed every 12 feet”.

Twenty years later, I beg to differ. Hansen Buildings has buildings in each of the 50 states and all of them have roof trusses on what my board member friend would describe as being “widely spaced”.

Modern truss design is highly computerized. Enter the span of the truss, bay spacing and load conditions and the engineering programs will design a truss which will meet the design criteria. The lumber and steel plates the trusses are constructed from, have no idea how far apart they are going to be placed.  They are inanimate! Yet, somewhere in the deep, dark reaches of history, lies the theory wood trusses must be spaced no more than 24” on center, or maybe 48”, or perhaps even eight or ten feet? The reality is, there is no magic number.

Framed Pole Barn

36′ long garage with 12′ bays

While D. Howard Doane is credited with being the innovator of the modern pole barn, it was his Agricultural Service farm manager, Bernon Perkins, who is credited with refining the evolution of the modern pole building to a long-lasting structure.  It was Perkins who pioneered roof purlins being placed on edge. With this design change, roof trusses could be placed 12 feet apart, making it possible for roofs to support the loads to which they would be subjected.

I’ve had roof truss manufacturers try to convince me it is impossible to place wood trusses at spacings of over every 4 feet. Their defense is, “Our engineers will not allow us to”. The manufacturers of the steel roof truss plates (also referred to as gussets or Gang-nails), provide the engineering design for pre-fabricated wood trusses. Their programs will allow for trusses to be placed on 12 foot or even 16 foot centers, and their engineers will place their engineer’s seal on the drawings to verify.

The practicality, cost effectiveness and ease of construction of pole buildings is based upon efficient use of the fewest amount of materials, to do the most work, within safe engineering design. Hundreds of thousands of pole barns are in use today with trusses spaced every 12 feet, or even more. They stand as a tribute to the ingenuity of modern pole building design.