What Are HUD Snow and Roof Load Zones for Manufactured Homes?

HUD roof load zones for manufactured homes divide the country into three areas based on how much downward weight from snow, ice, and rain a home’s roof must be built to carry: 20 pounds per square foot in the South Zone, 30 psf in the Middle Zone, and 40 psf in the North Zone. The zones are set at the county level under federal regulations, and a home rated for one zone cannot legally be installed in a zone with a higher requirement.¹

The Three Zones and Where They Apply

The structural requirements at 24 CFR 3280.305(c)(3) define “live load” as the weight of snow, ice, rain, and similar temporary pressures on the horizontal projection of the roof, separate from the weight of the roofing materials themselves.¹

The South Zone is the default at 20 psf. Every state and county not specifically listed in one of the other two zones falls here, which covers the largest geographic area: the southern, southeastern, and much of the western United States.

The Middle Zone requires 30 psf and applies to specific counties in 15 states across the upper Midwest, northern New England, and parts of the Rocky Mountain region. Those states are South Dakota, Minnesota, Iowa, Wisconsin, Michigan, New York, Massachusetts, Maine, Montana, Idaho, Colorado, Wyoming, Utah, Vermont, and New Hampshire. Only certain counties within each state qualify, not the whole state.

The North Zone requires 40 psf and is the most restrictive. It covers all of Alaska and eight counties in northern Maine: Aroostook, Piscataquis, Somerset, Penobscot, Waldo, Knox, Hancock, and Washington.

Because the boundaries run along county lines, two neighboring towns can sit in different zones. The regulation includes maps that manufacturers and installers use to confirm which zone applies to a given address.¹

What Each Rating Means for the Way the Roof Is Built

The 20 psf floor in the South Zone doesn’t assume zero snow. It covers occasional light accumulation, heavy rain, and the maintenance loads of workers walking on the roof. Manufacturers hit this number using standard truss spacing and lighter-gauge materials.

The 30 psf Middle Zone rating is a 50% increase over the South Zone and usually means closer truss spacing, heavier lumber grades, or both. It reflects areas where a few moderate snowfalls a year are expected and snow may sit on the roof for days or weeks during cold stretches.

At 40 psf, North Zone homes use the heaviest truss configurations the standard calls for, engineered for regions where sustained snowpack is a winter-long reality. Forty psf is a minimum, and manufacturers can build to higher ratings when a customer or site requires it.¹

Where 40 psf Is Not Enough

Plenty of high-altitude and mountain West locations see ground snow loads well above what even the North Zone covers. The regulation addresses this at 24 CFR 3280.305(c)(3)(ii): when recognized snow records or state and local authority requirements show loads significantly above the standard zones, HUD can establish more stringent requirements through rulemaking. For snow specifically, the rule uses 60% of the ground snow load in wind-exposed areas and 80% in sheltered areas as the basis for a higher roof load requirement.¹

A community that believes its conditions warrant a higher standard can petition HUD to reconsider the applicable zone. That is the proper channel; local governments generally cannot impose their own construction standard on the home itself.

How to Check Your Home’s Roof Load Rating

Every manufactured home has a Data Plate permanently attached inside the unit, usually near the main electrical panel or in another visible, protected spot like the inside of a kitchen cabinet door or a bedroom closet wall. The plate is required by 24 CFR 3280.5 and lists the home’s key specifications, including the roof load zone and wind load zone it was designed for, the manufacturer’s name and address, the serial number, model designation, and date of manufacture.² It also includes small reproductions of the HUD load zone maps.¹

If the home was built to exceed the standard zone load, such as a custom order rated for 60 psf, the actual design load appears on the plate instead of just the zone name.

The Data Plate is not the same thing as the HUD certification label, which is a small aluminum tag riveted to the exterior of each transportable section, typically near the taillight end about a foot up from the floor. That label certifies federal compliance and carries a unique number, but it does not list the load ratings. For the ratings, you need the Data Plate inside.³

If the Data Plate Is Missing

You can order a replacement Data Plate or Performance Certificate through the Institute for Building Technology and Safety, which maintains records on manufactured homes. Fees range from $125 for standard seven-business-day processing to $250 for same-day service. If the exterior HUD certification label is missing instead, a Label Verification Letter costs between $75 and $250 depending on turnaround. Orders arrive by email as a PDF; a mailed hard copy costs an additional $10.⁴

Getting this documentation matters beyond curiosity. Lenders, insurers, and local permitting offices routinely require proof of the home’s design specifications before approving financing, writing a policy, or issuing an occupancy permit. A missing Data Plate can stall a sale or installation for weeks.

Moving a Manufactured Home Between Zones

The installation standards at 24 CFR 3285.103(b) prohibit placing a home in a roof load zone that exceeds its design rating. A South Zone home rated for 20 psf cannot legally be installed in a Middle or North Zone location. That applies whether the home is new or being relocated.⁵

For sites with snow loads above 40 psf, additional installation requirements kick in under 24 CFR 3285.315. The foundation must be designed by the manufacturer or a licensed professional engineer to handle the extra load, and the home’s installation instructions must include specifications for the special snow load conditions. If the standard instructions do not cover the situation, an engineer or registered architect must certify the foundation design.⁶

Before moving a home, check three things: the roof load zone on the Data Plate, the zone designation for the destination county under 24 CFR 3280.305(c)(3), and any local foundation or anchoring requirements. Professional installers should verify all three, but the responsibility ultimately rests with the homeowner.

Local Building Codes and Federal Preemption

Manufactured homes differ from site-built houses here in a way that surprises many buyers. Under 42 U.S.C. §5403(d), federal manufactured home construction standards preempt state and local law. No state or local government may establish or enforce a construction or safety standard that differs from the federal standard on the same aspect of performance, and the statute directs that this preemption “shall be broadly and liberally construed” to protect the uniformity of the federal system.⁷

So a local building department cannot look at a North Zone home rated for 40 psf and demand it be rebuilt to 60 psf. The proper path is a petition to HUD to reclassify the area.

Two carve-outs matter. First, each state retains authority to set standards for the stabilizing and support systems (anchoring and tie-downs) and the foundations under manufactured homes, as long as those standards are consistent with the manufacturer’s design.⁷ Second, local governments can require onsite mitigation measures for geographic and climatic conditions, such as extra foundation support or site grading, as long as those measures do not alter the home’s design and construction. A locality can require your foundation to handle heavier loads. It cannot require a different roof at the factory.

Warning Signs Your Roof Is Overloaded

Manufactured homes with flat or low-slope roofs are especially vulnerable to snow accumulation because they shed snow slowly and hold moisture. Even a properly rated roof can be overwhelmed by an unusual storm or by snow that melts and refreezes into much heavier ice. FEMA identifies these warning signs:

Sagging ceiling tiles or boards, or panels dropping out of the grid
Popping, cracking, or creaking sounds from structural members
Doors or windows that suddenly bind and won’t open or close
Visible bowing of truss members in attic spaces, including curved bottom chords or bent webs
New stress cracks in walls where none existed
Roof leaks that start during heavy snow rather than rain

If you notice any of these, evacuate first and clear snow second. A collapsing roof gives very little warning once it reaches the failure point. When snow does need to come off, FEMA recommends leaving a couple of inches on the surface to avoid gouging the roofing, using plastic shovels or non-metallic rakes rather than metal tools, and working from a long-handled roof rake on the ground when possible. Remove drifts first, especially at elevation changes and around rooftop equipment, and never pile removed snow onto another section of the roof.⁸

1
eCFR. 24 CFR 3280.305 – Structural Design Requirements
2
eCFR. 24 CFR 3280.5 – Data Plate
3
eCFR. 24 CFR 3280.11 – Certification Label
4
Institute for Building Technology and Safety. Manufactured Home Certifications
5
eCFR. 24 CFR 3285.103 – Site Suitability With Design Zone Maps
6
eCFR. 24 CFR Part 3285 – Model Manufactured Home Installation Standards
7
Office of the Law Revision Counsel. 42 USC 5403 – Construction and Safety Standards
8
FEMA. Snow Load Safety Guide