Manufactured Homes in Idaho: A Unique Inspection List

Manufactured (mobile) homes are a popular, affordable housing option across Idaho. However, they are built to a different standard (HUD Code) than site-built homes (IRC Code) and have unique maintenance requirements.

1. The Structure and Tie-Downs

Unlike a house on a concrete foundation, a manufactured home sits on a steel chassis. In Idaho/wind zones, these homes must be securely anchored to the ground to prevent tipping or sliding during high winds.

We check for:

• Tie-down straps: Are they present? Rusted? Loose?
• Piers and pads: Are the concrete blocks cracked or sinking?
• Leveling: If the home isn't level, doors won't shut and windows may crack.

2. The Crawlspace (Skirting)

The space under a manufactured home is vulnerable. The skirting (the material covering the gap between the ground and the home) acts as the home's "foundation walls."

Common issues:

• Inadequate Ventilation: Without proper vents, moisture builds up, rotting the floor joists from below.
• Rodent Holes: Skirting often gets damaged by weed eaters, providing a perfect highway for mice, skunks, and cats to move in and tear up insulation.
• Vapor Barrier: The ground underneath should be covered with plastic to stop soil moisture from rising up.

3. Plumbing Quirks

Older manufactured homes (pre-1995 especially) often used Polybutylene piping. This grey plastic pipe is notorious for failing and causing catastrophic floods. Many insurance companies will not cover a home with Polybutylene.

We also check the belly board (the heavy plastic sheet under the floor insulation). If plumbing leaks occur, they often pool in the belly board, sagging down like a water balloon and causing massive hidden rot.

4. Roofing Challenges

Many older units have "rumble roofs" (metal roofs that are often coated/sealed repeatedly). We look for:

• J-Fan leaks: The vents often leak.
• Coatings: Has the roof been coated properly, or is it peeling?
• Over-roofs: Has someone built a heavy wood roof over the original structure? This can crush the walls if not supported properly.

5. Modifications and "Additions"

This is the big one. We often see DIY additions (porches, extra rooms) bolted to the side of the home. Manufactured homes are engineering marvels designed to support their own weight—not the weight of an extra room hanging off the side. Improper additions can torque the frame and cause structural failure.

TL;DR Summary

• Anchors are key: Check the tie-downs for safety.
• Guard the skirt: Keep rodents out and ventilation open.
• Watch the pipes: Polybutylene is a deal-breaker for many insurers.
• Beware DIY: Additions must be self-supporting, not leaning on the home.

Manufactured homes can be great, safe housing, but they require a specialized eye for inspection.