Ask ten people how a pole barn is held together and you will hear about posts, trusses, and steel. Very few mention the thousands of nails and screws that actually tie those parts into one building. Fasteners are small, but they decide whether a truss stays put in a straight-line wind, whether a treated post stays strong for decades, and whether your roof stays dry through a Minnesota winter. This guide explains where nails belong in pole barn construction, where screws do the job better, and what to ask your builder before the first post goes in the ground.
Why Fasteners Matter So Much in Post-Frame Buildings
Post-frame buildings work as a system. Wood posts carry the roof and resist wind. Wood trusses span the width of the building. Girts and purlins run horizontally to stiffen the frame and give the steel something to attach to. Every one of those connections depends on a fastener, and each connection sees a different kind of force.
Some joints mostly resist sideways shear, like a girt nailed to the face of a post. Some resist pull-out, like a truss that wind is trying to lift off its post. The steel skin sees all of it plus daily expansion and contraction. In east-central Minnesota, where our service area spans Climate Zones 6A and 7, buildings swing from humid summer heat to deep winter cold, so fasteners are working year-round.
That is why the honest answer to the nails versus screws debate is not one or the other. Good post-frame construction uses each where it performs best, and follows the engineered drawings for the rest.
Where Nails Still Earn Their Place
Nails get a bad reputation because people picture a smooth nail working loose from an old shed. The nails used in professional post-frame construction are a different animal.
Ring-Shank Post-Frame Nails
Ring-shank nails, often called pole barn nails, are hardened steel nails with annular rings along the shank. Those rings lock into the wood fibers and resist withdrawal far better than a smooth nail. The National Frame Building Association notes that post-frame ring-shank nails are produced to the ASTM F1667 standard, which is referenced in the National Design Specification for wood construction, and that they have exceptional withdrawal resistance.
Nails are also very good in shear. Because they are ductile, they bend before they snap, which is useful when a building flexes under wind or snow. They go in fast, which keeps labor time reasonable on framing connections where hundreds of fasteners are needed.
Nail-Laminated Posts
Many modern pole barns use laminated posts built from several layers of lumber rather than one solid timber. NFBA guidance specifies that the layers of mechanically laminated posts are joined with ring-shank nails according to the design calculations or the manufacturer's engineered nailing pattern. This is factory or engineered work, and the nailing schedule is not something a crew should improvise.
Where Screws Do the Job Better
Screws hold by threading into the material, which gives them strong pull-out resistance and lets them clamp parts tightly together. That makes them the right choice in several places on a pole barn.
Steel Roofing and Siding
Exposed-fastener steel panels are attached with self-drilling screws that have a sealing washer under the head. The washer is what keeps water out, so installation matters. Screws should be driven straight, into solid framing, and tightened until the washer seals without being crushed. Roofing guidance commonly warns that overdriving splits the washer and underdriving never seals.
Washer material matters too. Many builders prefer EPDM washers over neoprene because EPDM holds up better under sunlight. Ask what your builder uses and how long the fastener manufacturer expects it to last.
Heavy Structural Connections
The connection between a truss and its post is one of the most important joints in the building. It carries the roof's weight and has to resist wind uplift. Depending on the design, it may use bolts, structural screws, ring-shank nails, steel brackets, or a combination. NFBA technical material notes that self-drilling structural screws of roughly a quarter inch in diameter have become popular for truss-to-post connections because they install quickly and consistently. Whatever the method, the engineered drawings should spell it out, and the crew should follow it exactly.
Treated Wood Changes the Rules
The posts in a pole barn are pressure-treated so they can sit in the ground without rotting. The preservatives that protect the wood can also corrode ordinary steel fasteners, which is why the code is specific here.
The 2020 Minnesota Residential Code, adopted in Minnesota Rules chapter 1309, is based on the 2018 International Residential Code. Section R317.3 of that code requires fasteners in preservative-treated wood, including nuts and washers, to be hot-dipped zinc-coated galvanized steel, stainless steel, silicon bronze, or copper, with limited exceptions such as half-inch or larger steel bolts. It also requires staples in treated wood to be stainless steel. The MNRC governs one- and two-family homes and their accessory structures, so it applies directly to post-frame homes, shouses, and many residential garages and shops.
For the in-ground portion, NFBA guidance calls for posts treated to Use Category UC4B or better and fasteners galvanized to ASTM A153 or made of stainless steel. Post embedment depth is set by the building's engineering and local frost depth. Under Minnesota Rule 1303.1600, Aitkin, Kanabec, Mille Lacs, and Pine counties fall in the 5-foot frost zone, while Isanti and Chisago counties fall in the 3.5-foot zone.
Minnesota is also reviewing an update to the residential code based on the 2024 IRC. The Department of Labor and Industry has an open rulemaking docket with the effective date still to be determined, so for now the 2020 MNRC remains the code to plan around.
Common Fastener Problems and How to Avoid Them
Most fastener trouble on pole barns traces back to a handful of causes. Knowing them helps you ask better questions and spot issues early.
- Backed-out roof screws. Steel panels expand and contract every day, which can slowly work screws loose and leave a gap under the washer.
- Over- or under-driven screws. A crushed washer or one that never seated is a leak waiting to happen.
- Screws that miss the purlin. A screw that only goes through steel will not hold or seal for long.
- Wrong coating against treated wood. Non-rated fasteners in treated posts can corrode out of sight.
- Skipped engineering details. Missing nails in a laminated post or a lighter truss connection than the drawings call for weakens the whole frame.
When a roof screw does back out, simply snugging it down is usually a short-term fix because the wood around it is already compressed. A common repair is to replace it with a slightly larger screw and a fresh washer driven into solid wood. A twice-a-year walkaround, in spring after the thaw and in fall before freeze-up, catches most problems while they are small.
What Affects Fastener Choices and Cost
Fasteners are a small part of a building's total cost, but the choices behind them affect long-term maintenance. Several factors shape what goes into your building:
- Building use and size, which drive wind and snow loads and the strength of every connection.
- Residential versus agricultural use, which affects which codes and inspections apply.
- Exposed-fastener versus hidden-fastener steel and the washer type selected.
- Coating level, from hot-dipped galvanized to stainless steel in harsher conditions such as livestock barns.
- Post type, whether solid-sawn or laminated, and the engineered connection details.
Because each project is different, the best way to understand these choices for your building is to request a quote and walk through the details with a builder.
Frequently Asked Questions
Are screws stronger than nails in a pole barn?
It depends on the joint. Screws resist pull-out and clamp tightly, while hardened ring-shank nails perform very well in shear and bend instead of snapping. Good post-frame construction uses both where each performs best.
What fasteners are required in treated posts in Minnesota?
Under section R317.3 of the 2020 Minnesota Residential Code, fasteners in preservative-treated wood must be hot-dipped galvanized steel, stainless steel, silicon bronze, or copper, with limited exceptions such as half-inch or larger steel bolts. Staples must be stainless steel.
Why do metal roof screws back out?
Steel panels expand in the sun and contract at night. Over the years that movement can loosen screws, especially ones that were over- or under-driven. Regular inspections and replacing failed screws with properly sized new ones keep the roof sealed.
How often should I check the fasteners on my pole barn?
A visual walkaround in spring and fall is a good habit, plus a check after any major windstorm. Look for raised screw heads, cracked washers, rust streaks, and loose trim.
Can I use regular deck screws to fix my pole barn?
Not for steel panels. Roofing and siding need screws made for steel cladding with a sealing washer. For connections in treated wood, use fasteners rated for treated lumber. For structural repairs, follow the building's engineering or talk to your builder.
Talk Through Your Pole Barn Details With Sherman
The best pole barns are built right in the details you never see once the steel goes on. If you are planning a shop, garage, barn, or post-frame home in Kanabec, Pine, Mille Lacs, Isanti, Chisago, or Aitkin County, stop by our Mora office or request a free, no-pressure quote. We will walk you through how your building goes together, from the posts in the ground to the screws in the roof, and answer your questions along the way.
