Delaware County, IA Roof Snow Load - 21 psf
Delaware County, IA roof snow load, translated
A typical heated home in Delaware 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.
Delaware County at a glance
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#458 of 2,758
- Iowa rank#34 of 99
- Population17,609
- Annual snowfall, NOAA normal34.7 in.
- FIPS19055
Where Delaware County ranks
#34 of 99 Iowa counties by design load, top 17% of 2,758 nationally - that's Delaware County's spot. 21.7 psf is Iowa's typical county figure - Delaware County comes in 0.7 psf under it.
FIPS 19055, population 17,609, centered near 42.473°N 91.3668°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.
Delaware County: average annual snowfall
Delaware County sees about 34.7 in. of snow most winters, per the MANCHESTER #2, IA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Delaware 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.)