Shed Roof (Monoslope) Snow Load Calculator
A shed or monoslope roof has one continuous slope, so the slope factor Cs applies straight to the flat-roof load. Single-slope roofs can also collect a windward drift along the high wall.
The worksheet
ASCE 7-22The balanced load of 25.2 psf governs (it exceeds the 20 psf minimum).
≈ 37,800 lb total on 1,500 sq ft of roof plan
Flat-roof load Pf = 0.7 × Ce(1) × Ct(1.2) × Is(1) × Pg(30) = 25.2 psf. Sloped-roof balanced load Ps = Cs(1) × Pf = 25.2 psf.
| Ground snow load, Pg | 30 psf | site input |
| Exposure factor, Ce | 1 | Table 7.3-1 |
| Thermal factor, Ct | 1.2 | Table 7.3-2 |
| Importance factor, Is | 1 | Table 1.5-2 |
| Slope factor, Cs | 1 | Fig. 7.4-1 |
| Snow density, γ | 17.9 pcf | Eq. 7.7-1 |
| Settled depth at design load | 17 in | design ÷ density |
- 01Estimated snow density ≈ 17.9 pcf, so 25.2 psf is roughly 17 in of settled snow.
- 02At roof steps, parapets and against walls check drift loads (§7.7) with the drift calculator, and check sliding snow (§7.9) where this roof sheds onto a lower roof, walk or equipment.
- 03Ground snow load Pg is set by your local building department / the ASCE 7 Hazard Tool. Always confirm the value for your exact site before you build or submit.
Sheds & barns rated for snow
Your design roof snow load is 25.2 psf. Metal and resin shed kits list a roof snow-load rating. Confirm it clears the design load above, especially for an unheated shed (Ct = 1.2).
Arrow, Suncast and Lifetime shed kits. The heavier-gauge and peak-roof models carry more snow.
Shop shed kitsTruss and rafter reinforcement kits that raise a kit shed's snow rating in a heavy-snow region.
Shop reinforcement kitsSome links are affiliate links: if you buy through them we may earn a commission at no extra cost to you. These are starting points, not engineering endorsements. Always confirm a product's rated snow load meets the design load above.
Notes for shed / monoslope roof roofs
- Sheds are usually unheated (Ct = 1.2), so they carry more snow than a heated house of the same slope.
- A monoslope roof against a taller wall can pick up a drift, so check the drift case if there's a roof step or parapet.
Notes & questions
01How do I calculate snow load on a shed roof?+
Use the ASCE 7 method: flat-roof load Pf from your ground snow load, then multiply by the slope factor Cs for the single slope. Sheds are usually unheated, so use Ct = 1.2. Enter the values above.
02Is a shed roof good for snow?+
A steeper monoslope sheds snow well in one direction, but it can throw a lot of snow off the low edge and drift snow against a tall wall on the high side, so plan where the snow goes.