How to Prepare Your Roof for Snow Loads Guide for Eastern Washington Homeowners & Contractors

Why Snow Load Prep Matters for Eastern Washington Roofs

If you’ve lived through a few winters in the Spokane area, Colville, or Kettle Falls, you already know our snow isn’t always the light, fluffy stuff you see in ski resort brochures. We get heavy, wet snow events, followed by hard freezes, followed by more snow on top of ice — and that combination is exactly what stresses a roof structure. Add in our region’s swing from bitter winters to hot, dry summers, and you’ve got a roof that’s working hard year-round.

Most homes in valley areas around Spokane are built to handle a ground snow load somewhere in the 20–40 psf range, but that number changes with elevation, and if you’re up in the hills around Colville or Kettle Falls, your actual design load could be considerably higher. The problem is, most homeowners have no idea what their roof was actually engineered to hold. That’s the first thing we tell customers who come into our Airway Heights, Colville, or Kettle Falls locations asking about roof prep — find out your number before you assume anything.

Understanding Snow Load Basics

Snow load design in Washington follows ASCE 7 standards and the Washington State Building Code, with local jurisdictions adopting specific ground snow load values based on elevation and historical data. As a rough rule of thumb, one inch of fresh, light snow can weigh around 0.5 psf, while wet, heavy snow can run 1.5 psf or more per inch. So a couple feet of dense, wet snow sitting on your roof after a warm spell can add up to serious weight fast — sometimes exceeding what an older roof was ever designed to hold.

Warning Signs Your Roof Is Under Stress

You don’t need to be a structural engineer to catch the early warning signs of a roof struggling under snow load. Walk your property after a heavy snow event and look for these red flags:

Visible Structural Signs

• Sagging ridge lines — the roof peak should be straight; any noticeable dip or bow is a serious concern
• New cracks in drywall, especially near where interior walls meet ceilings
• Doors or windows that suddenly stick or won’t latch properly, which can indicate the frame is shifting under load
• Popping or cracking sounds coming from the attic or roof during heavy snow accumulation

Drainage and Ice Dam Warning Signs

• Icicles forming in thick, heavy rows along the eaves — often a sign of an ice dam building up behind them
• Water stains appearing on interior ceilings near exterior walls
• Gutters visibly pulling away from the fascia under ice weight

If you see any of the structural signs, stop what you’re doing and call a contractor or licensed engineer. This isn’t a DIY situation — a compromised roof structure under active snow load is a safety issue, not a weekend project.

Prepping Your Roof Before Winter Hits

Fall is your window to get ahead of winter in Eastern Washington, and it’s a shorter window than a lot of folks think. Here’s what we recommend walking through before the first real snow of the season.

Get an Inspection

Have a contractor or roofer walk your roof and attic before the snow flies. This is especially important if your home is older, if you’ve added a second layer of roofing at some point, or if you’re in a higher-elevation area around Colville or Kettle Falls where design snow loads run higher than in the valley. A pre-season inspection should check:

• Overall condition of shingles, flashing, and roof penetrations
• Signs of existing sagging or stress in the framing
• Attic insulation depth and condition
• Ventilation — are soffit and ridge vents clear and functioning
• Gutter and downspout condition

Clean Gutters and Downspouts Thoroughly

This sounds basic, but clogged gutters are one of the biggest contributors to ice dams in our region. When gutters back up with leaves and debris, melting snow has nowhere to go, refreezes, and builds an ice dam that forces water backward up under your shingles. Clear everything out in the fall, and if you can, do a second check after leaves finish dropping.

Check Attic Insulation and Ventilation

This is the piece people underestimate most. If your attic is under-insulated or poorly ventilated, heat escapes into the attic space, warms the underside of your roof deck, and melts the snow sitting on top. That meltwater runs down to the cold eaves and refreezes — that’s your ice dam. Balanced soffit-to-ridge ventilation combined with adequate insulation keeps your roof surface temperature more consistent, which is one of the most effective things you can do to prevent ice dams across a Spokane-area winter.

Install Ice-and-Water Shield in Vulnerable Areas

If you’re re-roofing or doing repairs, self-adhered ice-and-water membrane along the eaves and in valleys gives you a real line of defense against ice dam backup. This is standard practice for anyone building or re-roofing in our climate, and we stock these underlayment products at all three of our locations.

Choosing the Right Roofing Materials for Snow Country

Not all roofing systems perform the same under heavy, repeated snow loads, and this is a conversation we have a lot with customers planning a re-roof.

Standing Seam Metal Roofing

For homes and outbuildings in the higher-snow areas around Colville and Kettle Falls, standing seam metal roofing is often the better long-term choice. Its smooth, slick surface sheds snow more readily than shingles, reducing the accumulated load sitting on the structure at any given time and cutting down on ice dam formation. If you install snow guards, they should be spaced according to your roof’s expected snow load and pitch — mounting them incorrectly can create hazardous slab-release situations near entries or walkways instead of preventing them.

Asphalt Shingles — Do It Right

Asphalt shingles remain common across Eastern Washington and work fine when installed on a properly insulated, ventilated roof. The mistake we see most often: homeowners adding a second layer of shingles over the old ones during a re-roof to save money. That extra layer adds dead weight to framing that may already be near its design limit for snow load — not a good trade-off in our climate. If your roof already has one layer, tear it off before adding new material.

Low-Slope and Flat Roofs

If you’ve got a shop, garage, or addition with a low-slope or flat roof, drainage is everything. Roofs like this need a minimum slope of about 3/8 inch per foot to avoid ponding, and ponding combined with a fresh snow load — especially during a rain-on-snow event — is one of the fastest ways to overload a structure. Keep drains and scuppers completely clear going into winter.

Safe Snow Removal Practices

Once winter’s here and the snow starts piling up, how you remove it matters just as much as whether you remove it.

Use a Roof Rake — Stay on the Ground

The safest way to remove roof snow for most homeowners is a long-handled roof rake, worked from ground level. A few practical pointers:

• Work from the edges of the roof toward the center, not the other way around
• Remove snow in layers rather than trying to clear it all in one pass
• Keep removal balanced — don’t clear one side of the roof and leave the other side heavily loaded, which can twist the structure unevenly
• Leave about 2–3 inches of snow on the roof surface to protect the shingles from rake damage
• Never use salt or de-icing chemicals on the roof — they can damage shingles and corrode metal flashing and fasteners

Avoid Walking on a Snow-Covered Roof

We can’t stress this enough: don’t climb onto a snow-covered roof unless it’s absolutely unavoidable. It’s slick, it’s dangerous, and your added body weight in one concentrated spot is exactly the kind of localized overload that can cause problems on a roof that’s already near capacity. If rooftop access is genuinely necessary — steep pitch, multi-story, hard-to-reach areas — that’s a job for a professional with proper fall protection equipment, not a ladder and a shovel on a Saturday afternoon.

Know When to Stop and Call a Pro

If you see sagging, hear cracking, or notice doors and windows suddenly binding during a heavy snow event, stop any DIY removal immediately and call a structural engineer or experienced contractor. This isn’t the time to save money — it’s the time to make sure everyone in the building is safe.

Costs and What Drives Them

Pricing varies by contractor and by year, but here’s a general sense of what affects cost for snow-prep-related work in our area:

• Pre-season inspections — cost depends on roof size and whether you need a basic roofer’s walk-through or a full engineering review; the latter costs more but is worth it if you have any doubt about your roof’s capacity
• Roof rake services — priced per visit, rising with roof pitch, complexity, and snow density
• Rooftop snow removal — significantly more expensive due to the fall-protection equipment and labor required, and rates climb fast during active storm periods
• Re-roofing with metal — a bigger upfront investment than shingles, but often pays off over time in high-snow areas through reduced ice dam issues and easier snow shedding
• Structural reinforcement — sistering joists or adding support members after an engineer’s assessment; cost depends heavily on attic accessibility and how much reinforcement is needed

Building a Winter Prep Checklist

Here’s how we’d summarize it for anyone in the Spokane area, Colville, or Kettle Falls getting ready for winter:

Before the Snow Flies

• Get a roof inspection and find out your roof’s design snow load if you don’t already know it
• Clean gutters and downspouts completely
• Check attic insulation depth and ventilation flow
• Pick up a roof rake and basic safety gear
• Confirm drains are clear if you have a low-slope roof

During Winter

• Monitor snow accumulation and watch for structural warning signs
• Use a roof rake for ground-based removal when accumulation gets heavy
• Never walk on a snow-loaded roof
• Call a professional at the first sign of sagging, cracking, or misaligned doors/windows

Planning Ahead

• When it’s time to re-roof, consider standing seam metal for better snow shedding, especially at higher elevations
• Never add a second shingle layer without a structural review
• Work with a design professional for any new construction or major roofing changes to make sure you’re meeting current Washington snow load requirements

Getting your roof ready for an Eastern Washington winter isn’t a one-time task — it’s a combination of knowing your numbers, staying ahead of maintenance, and using the right materials for our specific climate. We carry ice-and-water shield, roof rakes, ventilation products, standing seam metal roofing components, and everything else mentioned in this guide at our Airway Heights, Colville, and Kettle Falls locations. Stop in or shop online, and our team can help you figure out exactly what your roof needs before the next storm rolls through. Browse our full selection at https://bldrsupply.epicor-inet.com/departments.

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