Perry County, PA Roof Snow Load - 20 psf
Perry County, PA roof snow load, translated
A typical heated home in Perry County is designed to carry 20 pounds per square foot of snow on its roof, per ASCE 7-22. 17.5 psf is what the ground-load formula alone gives; Perry County's 20 psf low-slope minimum (§7.3.4) beats it, so that figure is the one that governs on flat and low-pitch roofs.
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.
Perry County in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#745 of 2,758
- Pennsylvania rank#35 of 38
- Population46,816
- Annual snowfall, NOAA normal27.7 in.
- FIPS42099
Where Perry County ranks
#35 of 38 Pennsylvania counties by design load, top 27% of 2,758 nationally - that's Perry County's spot. That's 0.9 psf below Pennsylvania's own county-average design load of 20.9 psf.
FIPS 42099, population 46,816, centered near 40.3978°N 77.2663°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.
Perry County: average annual snowfall
Perry County sees about 27.7 in. of snow most winters, per the CARLISLE WTP, PA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Perry 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. See the methodology guide.