Washington County, RI Roof Snow Load - 21 psf
Washington County, RI roof snow load, translated
A typical heated home in Washington 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. 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.
Washington County, RI: quick facts
- Design roof snow load21 psf
- Ground snow load, ASCE 7 map30 psf
- National rank#414 of 2,758
- Rhode Island rank#3 of 5
- Population130,333
- Annual snowfall, NOAA normal34.5 in.
- FIPS44009
Where Washington County ranks
#3 of 5 Rhode Island counties by design load, top 15% of 2,758 nationally - that's Washington County's spot. That's 0.7 psf below Rhode Island's own county-average design load of 21.7 psf.
FIPS 44009, population 130,333, centered near 41.3968°N 71.6203°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.
Washington County: average annual snowfall
Washington County sees about 34.5 in. of snow most winters, per the KINGSTON, RI US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Washington 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.