Jasper County, IA Roof Snow Load - 20 psf
Jasper County, IA roof snow load, translated
A typical heated home in Jasper County is designed to carry 20 pounds per square foot of snow on its roof, per ASCE 7-22. ASCE 7's low-slope-roof minimum (§7.3.4) raises the governing figure to 20 psf - higher than the 17.5 psf the ground-load formula alone would give, and the code says use the larger one.
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.
Jasper County, IA: quick facts
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#795 of 2,758
- Iowa rank#55 of 99
- Population38,107
- Annual snowfall, NOAA normal27.7 in.
- FIPS19099
Where Jasper County ranks
#55 of 99 Iowa counties by design load, top 29% of 2,758 nationally - that's Jasper County's spot. 21.7 psf is Iowa's typical county figure - Jasper County comes in 1.7 psf under it.
FIPS 19099, population 38,107, centered near 41.6856°N 93.0541°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.
Jasper County: average annual snowfall
Jasper County sees about 27.7 in. of snow most winters, per the GILMAN, IA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Jasper 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. (How this figure is calculated.)