Snow Load Ratings, Explained

Snow is the patient load. Wind hits a structure and moves on; snow lands, stays, and accumulates — quietly adding weight for days or weeks. That's why snow gets its own rating on a structure's spec sheet, and why the units are different: not miles per hour, but pounds per square foot. Our kits are engineered to a 60 PSF snow load rating. Here's how to read that number like an engineer instead of like an ad.

What PSF actually measures

Pounds per square foot is exactly what it sounds like: the weight sitting on each square foot of roof. The tricky part is that snow depth tells you surprisingly little about snow weight. Density is everything — a foot of dry powder and a foot of saturated, late-season snow are wildly different loads, and rain falling onto an existing snowpack can add weight faster than any snowfall. This is why engineers and building officials talk in pounds, not inches, and why "it never snows that deep here" is not a load analysis.

Ground load versus roof load

Building codes start from a ground snow load — the design weight of snow on open ground in your area, based on decades of records. From there, engineering translates ground load into roof load, which is usually different: wind strips snow from some parts of a roof and piles it into drifts on others, sloped surfaces shed, and nearby taller structures can dump or shadow snow onto a lower roof. The translation from ground to roof — including drifting and unbalanced cases — is generally performed under ASCE/SEI 7, the load standard that model building codes reference.

The practical takeaway for a buyer: the number that governs your project is assigned locally. Your building department — the authority having jurisdiction — sets the design snow load for your address, and mountain jurisdictions in particular can require values that flatland buyers would not believe.

What our 60 PSF rating means

When we say our kits carry a 60 PSF snow load rating, we mean the engineering — frame, connections, and anchorage as a system — is performed to that design load, and the result is documented in the engineer-stamped, permit-ready drawings that ship with every kit, from carports to gazebos. It's the same system logic behind our wind rating, which we unpacked in What a 185 MPH Wind Rating Means: a rating describes what the engineering targets, and the stamped drawings are what make it usable at a permit counter. If a permit is in your future, our walkthrough of how carport permitting works covers the rest of that counter visit — the call, the paperwork, the inspections.

And the same honesty applies. A rating is not a guarantee against every winter, and it assumes the structure is assembled and anchored per the drawings. If your jurisdiction's required load exceeds the standard rating, site- and state-specific engineering is available — heavy-snow country is exactly what that option exists for.

The roof material question

Snow country buyers choosing between roof options should think about shedding. As a general matter, smooth metal roofing tends to release snow more readily than granular shingle surfaces — one factor among several in the choice. Our carport and gazebo kits take either metal or asphalt-shingle roofing, both pre-engineered to attach (the roofing itself is sourced separately — it is not included in the kit), and our metal vs. asphalt roofing guide walks through the full comparison beyond snow behavior alone.

Questions worth asking — anywhere you shop

• What snow load rating is the structure engineered to, in PSF?
• Is that rating documented in engineer-stamped drawings a plan reviewer will accept?
• What design snow load does my building department assign my address?
• If my required load is higher than the standard rating, can the seller engineer for it?

Any seller of engineered structures should answer all four without flinching. Ours: 60 PSF, yes, ask your AHJ, and yes — site- and state-specific engineering where conditions require it. Request a free quote and tell us what winter looks like where you are; we'll spec the structure to match.