Mobile home skirting is the wall of the crawlspace under your home. It closes the gap between the bottom of the siding and the ground so wind, weather, animals and debris stay out, and it sets how air and moisture move under your floor. It is not trim. The federal model installation standard, 24 CFR Part 3285, treats it as part of the installation, and two failures cause most of the trouble: wind gets behind it and lifts it off, and it traps moisture against a floor that cannot dry downward.
Almost every page that ranks for this term sells panels. This one explains the system the panels belong to, and points you at the rule that governs your own lot.
Why a manufactured home has a skirted crawlspace at all
Your home is not sitting on a foundation wall. It sits on a steel chassis, two long I-beams with cross members, resting on piers set on footings. Under the floor is the belly board, also called the bottom board, a membrane that holds the floor insulation up and wraps the ducts and water lines. Between it and the dirt is an open air pocket, and skirting is the curtain around that pocket.
That is why crawlspace advice written for a site-built house does not transfer. A masonry crawlspace wall carries load and sits below the frost line. Skirting carries nothing, so it cannot brace, support or level anything, and no amount of skirting fixes a pier problem. What it does control is air, water, animals and debris, which turns out to be most of what goes wrong under a manufactured home.
What the HUD installation standard actually says about skirting
The section is 24 CFR 3285.504, "Skirting," part of the Model Manufactured Home Installation Standards. It is four sentences long, and it explains most of the skirting failures you can see from the road. Subsection (a) reads:
"Skirting, if used, must be of weather-resistant materials or provided with protection against weather deterioration at least equivalent to that provided by a coating of zinc on steel of not less than 0.30 oz./ft.2 of surface coated."
The other three matter just as much. Subsection (b) says skirting must not be attached in a way that can trap water between the siding and trim, or force it up into the wall cavities. Subsection (c) says all wood skirting within 6 inches of the ground must be pressure-treated to AWPA Standard U1 for Use Category 4A, or be naturally resistant to decay and termite infestation. Subsection (d) says skirting must not be attached in a way that impedes the contraction and expansion of the home's exterior covering.
Read those together and a pattern appears. Skirting is supposed to hang, shed water outward, and move. Most of the fixes people reach for do the opposite.
What the standard says about the space behind the skirting
The next section, 24 CFR 3285.505, is titled "Crawlspace ventilation," and no page on the first results page quotes it. It says a crawlspace with skirting must have ventilation openings, and sets their minimum net area as a ratio to the home's floor area. That area can be reduced when a vapor retarder is laid on the ground under the whole floor. The exact figures, and a worked example for your home, get their own guide, because the numbers on the retail pages disagree with each other and with the text.
The rest of the section is plain, and you can check it yourself in an afternoon. Openings go as high above the ground as practicable, on at least two opposite sides for cross-ventilation. They are covered full height and width with a perforated, corrosion-resistant and weather-resistant covering designed to keep rodents out, and where freezing occurs those covers must be the adjustable type that can open and close. There must be an access opening, sized and placed so utility connections under the home can be reached. And dryer vents and combustion air inlets must pass through the skirting to the outside.
Which rule actually applies to you
This is where most articles quietly mislead. 24 CFR 3285 is a model standard, and 3285.1 says what it covers: minimum requirements for the initial installation of new manufactured homes. A state that runs its own installation program must give residents protection that equals or exceeds the model standards, and may write its own rules to do it. Where a state has no program of its own, the model standards are the minimum. The standards also say plainly that they do not relieve anyone of other applicable codes, ordinances and laws.
So there are usually four layers, and you have to find yours:
- The HUD model standard, 24 CFR 3285, for the original installation. Construction of the home itself is a separate rule book, 24 CFR 3280.
- Your state installation program, run by a state administrative agency, which may adopt the model standard, replace it, or exceed it.
- Your county or city building department, which may want a permit or an inspection for skirting work.
- Your park lease, if you are on a leased lot. On a rented lot the park is often the first authority you answer to, ahead of the town.
Replacing skirting on a home installed years ago is a retrofit, not an initial installation, so the layer that governs it is usually the state, the county or the lease. Never assume a rule you read online is the rule on your lot.
The four ways mobile home skirting fails
It blows off. Wind does not usually rip panels apart. It gets underneath the home, pressurizes the crawlspace, and pushes the panels out of their channel from behind. The instinct is to screw the tops tight to the siding, which works against 3285.504(b) and (d) at the same time: it traps water, and it stops the siding moving.
It traps moisture. Close the vents, skip the ground vapor retarder, or seal the skirting into the dirt, and ground moisture has nowhere to go but up into the belly board and onto cold duct surfaces. HUD's research publication "Moisture Problems in Manufactured Homes: Understanding Their Causes" names ground moisture as the largest single moisture load on a home. Condensation under a home in dry weather is physics, not a leak.
Animals get in. A gap at the bottom track, a missing access door, or a vent cover that has rusted through is an invitation. 3285.505(d) calls for vent coverings designed to prevent rodent entry for exactly this reason. Exclusion is a perimeter job, not a question of what you put under there afterward.
It rots or rusts at the ground. Untreated wood in contact with soil fails, which is what 3285.504(c) exists to prevent. Metal skirting wicks and corrodes along the bottom edge where water sits, and vinyl goes brittle at grade after enough freeze and thaw cycles.
Choosing a material, without ranking one
Vinyl skirting, metal skirting, insulated skirting, faux stone panels and poured or block masonry can all meet the weather-resistance test in 3285.504(a) when they are installed the way they were designed to be. The real trade-offs are elsewhere: how exposed your lot is to wind, what will hit the skirting (a weed trimmer, a mower, a snow plow, kids), how much your ground moves through the year, and whether the system still leaves you the ventilation openings, the adjustable covers and the access opening the standard calls for. Insulated skirting adds one more question, because anything that slows heat loss also moves where the dew point sits under your floor. Each of these gets its own comparison, and none of them gets a winner.
Installing, repairing and getting through winter
Installing. Most systems are the same three parts: a top rail fastened near the bottom of the siding, a bottom track or ground channel, and panels that sit loose between them so they can expand and contract. In exposed locations, wind rods or braces go behind the panels to hold them in the channel. Panels rigidly fixed at both ends are the ones that crack.
Repairing. A single cracked or missing panel is usually a panel job, not a re-skirt, as long as the tracks are straight and the ground has not moved under them.
Winter. Adjustable vent covers exist because the standard requires them where freezing occurs, but closing them is a decision with moisture consequences, and it depends on whether you have a ground vapor retarder. Heat tape on water lines under a home is its own subject, with a Consumer Product Safety Commission fire warning attached, and it is not something to guess at.
Here is where you stop
If your skirting gaps are changing along one wall, if panels that used to meet the siding no longer do, or if the top rail is pulling away, that is often the home moving rather than the skirting failing. Leveling, blocking, piers, footings, straps and anchors are the work of a licensed manufactured home installer working under your state installation program. Do not shim, jack or tighten anything yourself, and never loosen, tension or cut an anchor strap.
Under the home, the same rule holds. Ducts, wiring, water lines, and gas or propane lines run through that space. If you find a damaged or disconnected gas or propane line, leave the area and call your LP supplier or a licensed plumber. Damaged wiring goes to a licensed electrician. Standing water or sewage goes to a licensed plumber, and the source gets found before the skirting is closed back up. Crawling under a manufactured home is low-clearance work with poor air movement. If you cannot see and reach what you need to without lying under the chassis, hire it out.
Deep dives in this series
This page is the map. Each of these gets its own guide, and this page will link to each one as it goes live.
Ventilation and moisture: How Many Vents Mobile Home Skirting Needs · The Ground Vapor Barrier Under a Mobile Home · Moisture Under a Mobile Home: The Condensation Cycle Nobody Explains · Should You Close Skirting Vents in Winter?
Install and repair: How to Install Vinyl Mobile Home Skirting So It Stays On · Skirting Blew Off Again · Repairing a Cracked, Dented or Missing Skirting Panel · Skirting on a Sloped or Uneven Lot · The Skirting Access Door
Materials: Vinyl, Metal, Insulated, Faux Stone or Concrete Skirting · Insulated Skirting: When It Helps, When It Traps Moisture · Skirting That Touches the Ground: Wood, Termites and the HUD Treated-Wood Line
Under the floor: Belly Board Repair · Sagging or Wet Underbelly Insulation · A Twice-a-Year Look Under Your Mobile Home · Water Under a Mobile Home With No Rain · A Soft Floor Near the Outside Wall · Your Dryer Vent Must Exit the Skirting
Winter: Heat Tape on Mobile Home Water Lines · Frozen Pipes Under a Mobile Home · Winterizing the Underside of a Mobile Home
Animals and park rules: Keeping Mice, Cats, Skunks and Snakes Out From Under a Mobile Home · Skirting Rules in a Manufactured Home Park
Frequently asked questions
Is mobile home skirting required?
Not by the sentence most people expect. The federal model standard's skirting section opens "Skirting, if used, must be…", so it sets conditions on skirting rather than requiring it. The requirement to have skirting at all usually comes from your state installation program, your county or city, your lender or insurer, or your park lease. Check those four for your own address.
How much ventilation does skirting need?
24 CFR 3285.505 sets a minimum net area of ventilation openings as a ratio to your home's floor area, and allows that area to be reduced when an acceptable vapor retarder covers the ground under the entire floor. Openings must also sit as high above the ground as practicable, on at least two opposite sides. The results page gives several different vent counts and none of them matches the text, so the ratio gets its own guide.
Can I use plywood for mobile home skirting?
Only with care, and possibly not where you live. 24 CFR 3285.504(c) requires all wood skirting within 6 inches of the ground to be pressure-treated to AWPA Standard U1 for Use Category 4A, or naturally resistant to decay and termite infestation. Untreated plywood sitting on soil is the failure that sentence exists to prevent. Your park lease or local code may prohibit wood skirting outright.
Why does my skirting keep blowing off?
Usually pressure from behind, not weak fasteners in front. Air gets under the home, the crawlspace pressurizes, and panels pop out of the track. Fastening the tops harder to the siding makes it worse and works against two parts of 3285.504 at once, trapping water and blocking the siding's expansion and contraction. Panels are meant to sit loosely between a top rail and a bottom track, with wind bracing where the site is exposed.
Sources: 24 CFR 3285.1 (Administration), 3285.504 (Skirting) and 3285.505 (Crawlspace ventilation), Model Manufactured Home Installation Standards, read via the Cornell Legal Information Institute. HUD User, "Moisture Problems in Manufactured Homes: Understanding Their Causes." Consumer Product Safety Commission guidance on heat tape.
{
"@context": "https://schema.org",
"@type": "Article",
"@id": "https://exteriornest.com/mobile-home-skirting#article",
"headline": "Mobile Home Skirting: What It Actually Does, What HUD Says, and What Goes Wrong Under There",
"description": "Mobile home skirting is the wall of your crawlspace. What HUD 24 CFR 3285 requires, which rules apply where you live, and why skirting fails.",
"image": "https://exteriornest.com/wp-content/uploads/{{FEATURED_IMAGE}}",
"author": {
"@type": "Person",
"@id": "https://exteriornest.com/#author-mobile-home-skirting",
"name": "{{AUTHOR_NAME}}",
"jobTitle": "{{AUTHOR_TITLE}}",
"url": "https://exteriornest.com/author/{{AUTHOR_SLUG}}"
},
"publisher": {
"@type": "Organization",
"@id": "https://exteriornest.com/#organization"
},
"datePublished": "2026-08-24",
"dateModified": "2026-08-24",
"mainEntityOfPage": {
"@type": "WebPage",
"@id": "https://exteriornest.com/mobile-home-skirting"
},
"about": {
"@type": "Thing",
"@id": "https://www.wikidata.org/wiki/Q6753080",
"name": "Manufactured housing"
},
"mentions": [
{
"@type": "Thing",
"@id": "https://www.wikidata.org/wiki/Q4010360",
"name": "Crawl space"
},
{
"@type": "Thing",
"@id": "https://www.wikidata.org/wiki/Q811595",
"name": "United States Department of Housing and Urban Development"
},
{
"@type": "Thing",
"@id": "https://www.wikidata.org/wiki/Q276854",
"name": "Vapor barrier"
}
]
}
Leave a Reply