Scott County, IA Roof Snow Load - 20 psf
Scott County, IA roof snow load, translated
A typical heated home in Scott County is designed to carry 20 pounds per square foot of snow on its roof, per ASCE 7-22. Flat and low-pitch roofs in Scott County are actually governed by ASCE 7's §7.3.4 minimum of 20 psf, not the 14 psf the ground-load formula alone would produce.
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. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.
Scott County at a glance
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map20 psf
- National rank#597 of 2,758
- Iowa rank#45 of 99
- Population175,601
- Annual snowfall, NOAA normal28.7 in.
- FIPS19163
Where Scott County ranks
#45 of 99 Iowa counties by design load, top 22% of 2,758 nationally - that's Scott County's spot. Iowa counties average 21.7 psf; Scott County runs 1.7 psf lower than that.
FIPS 19163, population 175,601, centered near 41.6421°N 90.6223°W. ASCE 7's underlying ground snow load here is 20 psf before the code's exposure and importance factors bring it to the 20 psf design figure above.
Scott County: average annual snowfall
Scott County sees about 28.7 in. of snow most winters, per the DE WITT, IA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Scott 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.