Tennessee Roof Snow Load Calculator
Ground snow load across the populated parts of Tennessee runs roughly 5 to 20 psf (low). The calculator below is pre-loaded with a typical Tennessee value of 10 psf. Change it to your confirmed site value and adjust the roof.
The worksheet
ASCE 7-22At 18.4° the §7.3.4 minimum does not apply, so the balanced load of 7 psf governs.
≈ 10,500 lb total on 1,500 sq ft of roof plan
Large gable roof (W > 20 ft): windward side at 0.3·Ps, leeward side at Ps plus a drift surcharge from the ridge.
surcharge 11.7 psf over 6.13 ft · hd 1.33 ft · γ 15.3 pcf
Flat-roof load Pf = 0.7 × Ce(1) × Ct(1) × Is(1) × Pg(10) = 7 psf. Sloped-roof balanced load Ps = Cs(1) × Pf = 7 psf.
| Ground snow load, Pg | 10 psf | site input |
| Exposure factor, Ce | 1 | Table 7.3-1 |
| Thermal factor, Ct | 1 | Table 7.3-2 |
| Importance factor, Is | 1 | Table 1.5-2 |
| Slope factor, Cs | 1 | Fig. 7.4-1 |
| Snow density, γ | 15.3 pcf | Eq. 7.7-1 |
| Settled depth at design load | 5 in | design ÷ density |
- 01Estimated snow density ≈ 15.3 pcf, so 7 psf is roughly 5 in of settled snow.
- 02The §7.6.1 unbalanced (leeward-drift) case is computed above for this gable/hip roof; at roof steps, parapets and walls also check drift loads (§7.7) with the drift calculator, plus sliding snow (§7.9) onto anything below.
- 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.
Reduce the load on an existing roof
Your design roof snow load is 7 psf. If the design load is close to your roof's capacity, the cheapest fix is to keep snow off it. These are the tools that do that.
A long-handled rake pulls snow off from the ground, cutting the load before it builds up. The first thing to buy in a heavy winter.
Shop roof rakesSelf-regulating heat cable along eaves and valleys stops the ice dams that trap meltwater and add weight.
Shop heat cableSome 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.
Finding your exact Tennessee ground snow load
The number above is a planning value, not a permit value. For Tennessee, get your site's design ground snow load from the ASCE 7 Hazard Tool or your local building department. Many Tennessee jurisdictions adopt a published county or town value. Because elevation drives the value here, two nearby sites can differ a lot, so always use the value for your exact address.