Grundy County, IA Roof Snow Load - 21 psf
Grundy County, IA roof snow load, translated
A typical heated home in Grundy County is designed to carry 21 pounds per square foot of snow on its roof, per ASCE 7-22.
On a roof that means 46.2 in. of fresh snow, 16.8 in. once it packs down, or 4.2 in. of solid ice - three very different piles for the same load. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Grundy County at a glance
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#467 of 2,758
- Iowa rank#39 of 99
- Population12,405
- Annual snowfall, NOAA normal32.3 in.
- FIPS19075
Where Grundy County ranks
#39 of 99 Iowa counties by design load, top 17% of 2,758 nationally - that's Grundy County's spot. That's 0.7 psf below Iowa's own county-average design load of 21.7 psf.
FIPS 19075, population 12,405, centered near 42.4033°N 92.7902°W. ASCE 7's underlying ground snow load here is 30 psf before the code's exposure and importance factors bring it to the 21 psf design figure above.
Grundy County: average annual snowfall
Grundy County sees about 32.3 in. of snow most winters, per the GRUNDY CTR, IA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Grundy 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.)