Jones County, IA Roof Snow Load - 20 psf
Jones County, IA roof snow load, translated
A typical heated home in Jones County is designed to carry 20 pounds per square foot of snow on its roof, per ASCE 7-22. The physics-based figure alone would be 17.5 psf, but ASCE 7's own low-slope minimum (§7.3.4) sets a floor of 20 psf for flat and low-pitch roofs here, which is the number that actually governs.
On a roof that means 44 in. of fresh snow, 16 in. once it packs down, or 4 in. of solid ice - three very different piles for the same load. This is a meaningful design load - most modern-code homes handle it fine, though an addition, a carport or a flat-roofed section can be a weak spot.
Jones County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#946 of 2,758
- Iowa rank#63 of 99
- Population21,116
- Annual snowfall, NOAA normal31.1 in.
- FIPS19105
Where Jones County ranks
#63 of 99 Iowa counties by design load, top 34% of 2,758 nationally - that's Jones County's spot. Iowa counties average 21.7 psf; Jones County runs 1.7 psf lower than that.
FIPS 19105, population 21,116, centered near 42.1251°N 91.1169°W. ASCE 7's underlying ground snow load here is 25 psf before the code's exposure and importance factors bring it to the 20 psf design figure above.
Jones County: average annual snowfall
Jones County sees about 31.1 in. of snow most winters, per the CASCADE, IA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Jones 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.