Where DIY Post-Frame Builds Go Wrong: Girts, Purlins, and Bracing Explained

If you’ve spent any time online, you’ve probably seen someone claim that building a post-frame (pole barn) structure is a simple DIY project. And while the concept is straightforward, the execution is where things often go wrong, especially when it comes to girts, purlins, and bracing.

These three components are critical to the strength, longevity, and safety of your building. When they’re done incorrectly, the results can be costly, or even dangerous.

Let’s break down where DIY builders commonly miss the mark.

1. Girts: More Than Just Something to Screw Steel To

Girts are the horizontal framing members attached to the posts, and they carry wind loads from the walls into the structure.

Where DIY Builds Go Wrong:

• Incorrect spacing
  Too wide, and your steel will flex, oil-can, or even pull loose in high winds.

• Wrong orientation
  Many DIY builders install girts flat instead of on edge, dramatically reducing their strength.

Why It Matters:

Improper girts can lead to wavy walls, fastener failure, and reduced structural integrity in wind events.

2. Purlins: Your Roof’s Backbone

Purlins run horizontally across trusses and support your roof steel. They play a huge role in handling snow load and preventing sagging.

Common DIY Mistakes:

• Running purlins flat instead of on edge
  This is one of the biggest structural mistakes. On-edge installation greatly increases load capacity.

• Poor spacing
  Too far apart, and your roof panels can sag or fail under snow load.

• Inconsistent layout
  Uneven spacing leads to weak points across the roof system.

Why It Matters:

In northern climates like the Midwest, snow load is no joke. Improper purlin installation can result in roof deflection—or worse, collapse.

3. Bracing: The Most Overlooked (and Most Important) Piece

Bracing is what keeps your building square, rigid, and able to handle wind and shifting loads over time.

Where DIY Builders Cut Corners:

• Skipping diagonal bracing
  Without it, your building can rack (shift sideways), especially during high winds.

• No truss bracing
  Trusses are strong vertically, but weak laterally without proper bracing.

• Temporary bracing only
  Some builders remove bracing after construction, not realizing permanent bracing is required.

Why It Matters:

Without proper bracing, even a well-built structure can fail prematurely. Doors won’t close right, walls shift, and over time, the building loses structural integrity.

Real-World Consequences of Getting It Wrong

When girts, purlins, and bracing aren’t done right, you may see:

• Wavy or loose steel panels

• Roof sagging under snow

• Doors and windows going out of square

• Structural failure in high winds

• Costly repairs that exceed the original savings of DIY

The Bottom Line

DIY post-frame buildings can work, but only if they’re built with a clear understanding of structural principles. Girts, purlins, and bracing aren’t just “extra lumber”, they’re what make the entire building perform.

Cutting corners here doesn’t save money. It just delays the cost.

Thinking About Building?

If you're planning a post-frame building in the Twin Ports area or surrounding communities, make sure you're building it to handle local wind and snow loads, not just what “looks right.”

Need help or want it done right the first time?
Reach out today to discuss your project, get a quote, or get on our upcoming build schedule.