Union County, TN Roof Snow Load - 10 psf
Union County, TN roof snow load, translated
A typical heated home in Union County is designed to carry 10 pounds per square foot of snow on its roof, per ASCE 7-22. The physics-based figure alone would be 7 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 10 psf for flat and low-pitch roofs here, which is the number that actually governs.
On a roof that means 22 in. of fresh snow, 8 in. once it packs down, or 2 in. of solid ice - three very different piles for the same load. A modest addition to standard roof loading. Ordinary residential construction handles this without extra bracing.
Snow on Union County's roofs right now?
Union County in numbers
- Design roof snow load10 psf
- Ground snow load, ASCE 7 map10 psf
- National rank#1,900 of 2,758
- Tennessee rank#68 of 95
- Population21,064
- Annual snowfall, NOAA normal3.1 in.
- FIPS47173
Where Union County ranks
#68 of 95 Tennessee counties by design load, top 69% of 2,758 nationally - that's Union County's spot. That's 0.3 psf below Tennessee's own county-average design load of 10.3 psf.
FIPS 47173, population 21,064, centered near 36.2841°N 83.8361°W. ASCE 7's underlying ground snow load here is 10 psf before the code's exposure and importance factors bring it to the 10 psf design figure above.
Union County: average annual snowfall
Union County sees about 3.1 in. of snow most winters, per the NORRIS, TN US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Union County's figure
The figure above assumes the case ASCE 7-22 treats as typical: a heated, ordinary-occupancy home on a partially exposed site. Change any of those - exposure, heating, roof pitch, occupancy category - and the real design number moves.
A building permit needs the number at your exact address, not the county average - the free ASCE 7 Hazard Tool returns that from your coordinates in about a minute and produces a PDF a plan reviewer will accept. Details: the calculation guide.