Manassas city, VA Roof Snow Load - 20 psf
Manassas city, VA roof snow load, translated
A typical heated home in Manassas city 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; Manassas city'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. Modern-code homes carry a load like this without issue; an older addition, a carport, or any flat-roofed section is where it is worth checking first.
Manassas city in numbers
- Design roof snow load20 psf
- Ground snow load, ASCE 7 map25 psf
- National rank#767 of 2,758
- Virginia rank#30 of 110
- Population43,616
- Annual snowfall, NOAA normal21 in.
- FIPS51683
Where Manassas city ranks
#30 of 110 Virginia counties by design load, top 28% of 2,758 nationally - that's Manassas city's spot. 18.3 psf is Virginia's typical county figure - Manassas city beats it by 1.7 psf.
FIPS 51683, population 43,616, centered near 38.7468°N 77.4826°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.
Manassas city: average annual snowfall
Manassas city sees about 21 in. of snow most winters, per the WASHINGTON DC DULLES AP, VA US station's 1991-2020 NOAA normal. See the density guide.
Read this before you use Manassas city'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.)