SnowLoadCheck

Johnston County, NC Roof Snow Load - 15 psf

What ASCE 7 says about snow load in Johnston County

Moderate
15 psf

That's Johnston County's design roof snow load per ASCE 7-22, for a typical heated single-family home - the number a permit reviewer starts from. §7.3.4's low-slope minimum of 15 psf is what actually governs on a flat or low-pitch roof here - higher than the 10.5 psf the base ground-load formula gives.

Converted to something you can actually eyeball on a roof: about 33 in. of fresh powder, 12 in. once it settles and packs down, or just 3 in. if it's turned to ice. A meaningful design load. Most homes built to modern code handle it, but additions, carports, and flat-roofed sections are worth a second look.

Johnston County at a glance

Where Johnston County's figure sits nationally

Out of 2,758 rated US counties, Johnston County sits at #1,322, the top 48% nationally - #14 of 100 within North Carolina. North Carolina counties average 12.9 psf; Johnston County runs 2.1 psf higher than that.

Near 35.5134°N 78.3673°W, FIPS 37101: Johnston County counts 249,794 residents and a 15 psf map value, which the code's own factors turn into 15 psf.

How much it actually snows in Johnston County

Most winters bring Johnston County roughly 3.2 in. of snow - NOAA's normal at CLAYTON WTP, NC US, 10.3 mi off. (fresh vs. packed vs. ice explains why.)

Read this before you rely on it

Johnston County's number above is ASCE 7-22's default case, not a custom calculation: ordinary residential occupancy, heated, sited on ground that's neither fully sheltered nor fully exposed. Any one of those changing - pitch, exposure, heating, occupancy - moves the real figure.

Nothing here substitutes for an address-level number. Get one free, in about a minute, from the ASCE 7 Hazard Tool using your own coordinates rather than Johnston County's county-wide figure. See the methodology guide.