How to Build a Pole Barn — Getting Started Guide for Eastern Washington Homeowners & Contractors
Getting Started: What Every Eastern Washington Pole Barn Owner Needs to Know
If you’re planning a pole barn anywhere from Airway Heights to Kettle Falls, you’re dealing with a very different animal than a barn kit designed for Kansas or even the wet side of the Cascades. Our snow loads swing wildly by elevation, our winters get genuinely cold, and our soils range from sandy valley loam to rocky foothill ground. After decades of helping folks across Eastern Washington plan and build these structures, we’ve learned that the builds that go smoothly all start the same way — with good information before the first post ever goes in the ground.
This guide walks through the questions we hear most at our Colville, Kettle Falls, and Airway Heights counters, the local code and climate realities that trip people up, and the mistakes that turn a simple pole barn into an expensive headache.
Questions We Hear Every Week at the Counter
Design & Engineering
The most common question is some version of “what snow load do I actually need?” It’s a smart question, because Eastern Washington isn’t one climate zone — it’s several. Spokane County’s basic minimum roof snow load runs around 30 psf, but head up in elevation and you can hit 150 psf. Stevens County (Colville and Kettle Falls) sees some of the heaviest snow accumulation in the region, and a kit engineered for Spokane-area loads may be seriously undersized once you get up into the higher elevations north of town.
Right behind that comes: “Will the kit’s standard plans be enough, or do I need stamped engineering?” For anything beyond the most basic prescriptive pole building, you want site-specific, stamped engineering that accounts for your actual county, elevation, and exposure — not generic plans pulled from a catalog.
Permits & Codes
Customers are often surprised that “agricultural exempt” doesn’t mean “no rules.” Most counties still have size limits for simplified pole building approval — commonly a maximum truss span around 36 feet and a total area cap near 3,000 square feet before you’re required to bring in full engineering. Beyond that, you’re looking at footing, framing, and final inspections regardless of how rural your property is.
Cost & Budgeting
Everyone wants a number. We’ll give you real ranges below, but the honest answer is that cost is driven almost entirely by your snow/wind engineering, concrete, and door package — not just square footage.
Site, Soil & Future Use
We also get a lot of “will my soil hold embedded posts, or do I need piers?” and “can I insulate this later if I don’t need it now?” Both are worth planning for upfront, because retrofitting a barn is almost always more expensive than building it right the first time.
Eastern Washington Climate & Code Realities That Change Your Build
This is the section that separates a barn that lasts 40 years from one that has problems in year five. Eastern Washington’s climate isn’t gentle on outbuildings, and the code requirements reflect that.
Snow Load Varies More Than People Expect
In the Spokane area, minimum ground snow loads generally start around 39 psf with a 30 psf minimum roof snow load, but that number climbs fast with elevation. Once you’re up toward Colville, Kettle Falls, and the surrounding foothills and mountain fringes, roof snow loads can be dramatically higher than what a big-box or mass-market kit is engineered for. Always confirm your site-specific number with your county before you buy anything — don’t assume the barn down the road has the same requirement as yours, even if it’s only a few miles away and a few hundred feet higher.
Wind and Seismic Loads
Basic wind speeds in our region typically fall in the 85–110 mph range depending on exposure category, with most suburban and rural sites falling under Exposure B or C. Most of the Spokane area sits in Seismic Design Category C, meaning post connections, truss uplift resistance, and lateral bracing all need to be designed with both snow and seismic loads combined — not one or the other. This is exactly the kind of detail that a generic online kit calculator won’t get right for your property.
Frost Depth
Frost depth in the Spokane County area is typically around 24 inches, though it can run deeper in colder pockets to the north. Posts and piers need to be embedded below that frost line, full stop. Skimping here is one of the most common causes of heaving, racking, and doors that stop closing right a couple winters down the road.
Hot Summers, Cold Winters, Dry Air
Our summers bring intense UV exposure and heat, while winters bring sustained cold and ice. That combination means:
- Heavier-gauge steel roofing and siding hold up significantly better than thin, budget-grade panels that oil-can or dent under snow load and hail.
- Good roof drainage design and, in some assemblies, ice-shield underlayment help prevent ice-dam related damage.
- Heated shops need proper insulation and air sealing to avoid condensation forming on the underside of metal roofing — a common complaint we hear from owners who skipped this step.
- Rural properties should keep defensible space around the structure given our dry-season wildfire risk.
Soil and Site Conditions Across the Region
Valley floors around Airway Heights and the Spokane area tend to have workable loamy or sandy soils, while properties up toward Colville and Kettle Falls often run into rockier, shallower soil profiles. Neither is automatically a problem, but both require you to actually test and plan for what you’ve got rather than assume standard embedded posts will work everywhere. Poorly drained sites need swales, culverts, or French drains designed in before construction — not added after the pad starts holding water.
Permits Differ by County and City
Spokane County, the City of Spokane, and the more rural jurisdictions around Stevens County don’t all apply identical rules. Before you commit to a design, call your local building department and confirm permit requirements, any agricultural exemption limits, and whether your planned dimensions fall inside prescriptive limits or require full engineering review.
Mistakes We See Most Often — and How to Avoid Them
These are the issues that come up again and again with customers who are troubleshooting a barn that’s already built, or trying to fix a plan before it’s too late.
1. Buying a Kit Engineered for the Wrong Climate
The single biggest mistake is purchasing a pole barn package without confirming it’s engineered for your actual county’s snow load, wind exposure, and seismic category. A kit that passed permitting in a mild-snow region will not automatically work in Stevens County. Always ask directly: “What ground snow load is this engineered to, and does that match my elevation and county?” If a supplier can’t answer clearly, that’s a red flag.
2. Going Cheap on Steel Gauge
Thinner metal saves money upfront but dents easily, oil-cans under temperature swings, and has a shorter service life under our heavy snow and hail conditions. Heavier-gauge steel roofing and siding cost more initially but are worth it for a structure meant to last decades.
3. Skipping Real Site Prep
Grading, drainage, and compacted gravel base work needs to happen before posts go in — not after settling reveals a problem. A pole barn is only as solid as the pad underneath it. We see far more structural headaches from poor site prep than from framing errors.
4. Building Too Short
Eave height and door height are the number one long-term regret we hear about. If there’s any chance you’ll want to store an RV, larger truck, or add a lift down the road, plan for that height now. Going from a 10-foot to a 14-foot eave during initial construction is a minor upgrade; retrofitting it later is essentially a rebuild.
5. Trusting Online Price Calculators
Generic online pricing tools rarely account for your specific county’s snow load, wind exposure, or site conditions, so the numbers they generate often don’t reflect what you’ll actually pay in Eastern Washington. Use them for rough ballparking only.
6. Assuming “Ag Exempt” Means No Permits
Even agricultural buildings often have size thresholds, setback requirements, and inspection requirements. Skipping this step can create real problems later with insurance, financing, or resale.
7. Not Planning for Future Use
If there’s a reasonable chance you’ll insulate, heat, add electrical, or add a mezzanine later, it’s far cheaper to rough that in during the original build than to retrofit a finished structure.
Budgeting Realistically for an Eastern Washington Pole Barn
Most pole barns in Washington run somewhere between $25 and $55 per square foot depending on materials, engineering complexity, and finish level. Some bare-bones metal shell packages can come in lower, closer to $17 per square foot, but that’s typically shell-only pricing without concrete, insulation, or doors. National averages you might see quoted around $10–$40 per square foot rarely account for our snow and seismic engineering requirements, so it’s smart to budget toward the middle-to-upper end of the local range.
What Actually Drives Your Cost
- Engineering: Higher snow loads and Seismic Design Category C requirements increase truss and connection costs, but stamped plans are non-negotiable for a safe, permittable structure.
- Concrete: A full slab is often one of your largest line items, especially with reinforcement or insulation for a heated shop.
- Envelope quality: Heavier-gauge steel, better paint systems, and insulated doors cost more upfront but pay off in durability through our freeze-thaw cycles.
- Site work: Flat, well-drained sites near Airway Heights may need minimal grading, while rural or sloped properties near Colville and Kettle Falls can require significantly more excavation and drainage work.
- Height and size: Taller eaves and wider clear spans require larger posts and more substantial bracing.
DIY vs. Hiring a Pro
A hybrid approach works well for a lot of our customers: hire professionals for engineering, permitting, site work, and the primary shell, then handle interior finishing — insulation, wall liner, electrical rough-in, shelving — yourself. Smaller, simpler buildings (24×36 or 30×40, unheated storage, simple gable roof) are realistic full DIY projects for someone comfortable with layout and framing. Larger structures, anything approaching or exceeding the 3,000 square foot prescriptive limit, heated shops, or barndominium-style builds are where we strongly recommend bringing in experienced local contractors familiar with Eastern Washington snow and seismic requirements.
Your Next Steps
Before you buy a single post, walk through this checklist: confirm your use and desired eave height, check your site’s snow/wind/seismic requirements with your county, talk to your local building department about permits, get stamped engineering matched to your actual location, and plan your site work and drainage before anything goes in the ground. Getting these steps right from day one is what separates a pole barn that serves you for 40 years from one that starts causing problems in year five.
Our team at Builders Supply & Home Center has been helping Eastern Washington property owners plan and build pole barns since 1979, and we stock the posts, trusses, heavy-gauge steel roofing and siding, doors, insulation, and fasteners you need to do it right — whether you’re building near Airway Heights, up in Colville, or out toward Kettle Falls. Stop by any of our three locations to talk through your project with someone who understands our local snow loads and soil conditions, or browse our current inventory online at https://bldrsupply.epicor-inet.com/departments.