Resources
Glossary
Manufactured housing assumes you already know its vocabulary and rarely explains it. Every term here also says why it matters to a budget, because a definition on its own is trivia.
Belly wrap
Also called Bottom board, Belly board
The sealed membrane running across the underside of a manufactured home, below the floor joists. It holds the underfloor insulation in place and separates the floor system from the ground.
Why it matters: A torn belly lets ground moisture into the insulation, which then holds it against the underside of the deck continuously. It is the most common cause of a subfloor that keeps failing, and it never appears on a walk sheet because nobody looks underneath.
More on this →BLT
Also called Blocks, levelling and ties
Shorthand for the support and anchoring package under a manufactured home — the blocking and piers it sits on, the levelling of those piers, and the tie-down straps and anchors that resist wind uplift.
Why it matters: It is the part of the home nobody sees and nobody inspects. Settlement in the blocking shows up as cracked walls and doors that will not latch; failed anchoring shows up only in the weather it exists for.
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DAPIA
Also called Design Approval Primary Inspection Agency
The agency that reviews and approves a manufactured home manufacturer's designs and installation instructions under the federal HUD Code.
Why it matters: It matters because 24 CFR § 3285.3 says an alteration must not impose additional loads unless it is in the manufacturer's DAPIA-approved designs or is designed by a registered engineer or architect. That is the rule that decides whether a home can take a roof-over at all.
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HUD Code
The federal Manufactured Home Construction and Safety Standards, 24 CFR Part 3280, plus the related installation (3285) and licensing (3286) parts. It has governed manufactured home construction since 1976.
Why it matters: Manufactured homes are built to a federal standard, not to the local residential code. A contractor treating one as a small house is working to the wrong standard even when the workmanship is good.
Infill
Filling a vacant lot in an existing community with a home that reaches occupancy — covering transport, lot preparation, set, utility connection, skirting and make-ready, not just the day the home arrives.
Why it matters: It is the operator's word for the whole sequence, and the mismatch between it and the industry's narrower vocabulary ("home set", "installation") is where infill programmes lose months.
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Make-ready
Also called Turn
Bringing a vacant unit back to rent-ready condition. In a defined programme it is a written scope — demolition of what is failing, subfloor repair, flooring, walls, paint, kitchen and bath, fixtures, exterior and a documented clean.
Why it matters: Undefined, it means something different in every community, which makes cost per unit incomparable between markets. Defining it is the precondition for any portfolio-level analysis.
More on this →Marriage line
Also called Mate line, Centerline
The seam where the two halves of a double-wide manufactured home join after being set.
Why it matters: The two halves move independently with temperature and settlement. Flooring run continuously across it will buckle or gap, which is why a T-mould at the marriage line is an expansion joint rather than a trim choice.
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Park model
A smaller recreational unit built to a different standard from a HUD-code manufactured home, found in RV resorts, seasonal communities and mixed into manufactured housing communities.
Why it matters: Fixtures and cabinetry sourced on the assumption that a park model is a small manufactured home frequently do not fit — and the cost to turn one does not scale down proportionally with the square footage, because mobilization does not shrink.
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Roof Load Zone
The HUD design roof load region a manufactured home was built for, under 24 CFR § 3280.305 — North at 40 psf, Middle at 30 psf, South at 20 psf.
Why it matters: A home built for a 20 psf load has less spare structural capacity to absorb a roof-over's added dead load than an identical home built for 40 psf. Low design load is not headroom.
More on this →Roof-over
A new roof system installed directly over an existing manufactured home roof, without a tear-off.
Why it matters: No tear-off, demolition or disposal on a home that qualifies. Whether a home qualifies is a structural question governed by 24 CFR § 3285.3, and it is the most commonly skipped step in the category.
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Skirting
The panelling that closes the perimeter between the bottom of a manufactured home and the ground.
Why it matters: It controls the under-home environment — it keeps animals out, stops wind driving under the floor, protects the plumbing from freezing, and sets the appearance of the whole community. Under-ventilated skirting traps moisture and rots the belly.
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VOG
Also called Vinyl over gypsum
A gypsum wall panel with a decorative vinyl face applied at the factory, installed in most manufactured homes instead of drywall. Panels butt together and the seam is covered with a batten strip rather than taped and finished.
Why it matters: It is why the walls in a manufactured home have a vertical line every four feet, and why a damaged wall is a panel replacement rather than a patch. The vinyl face fades, so a new panel reads as new against aged walls.
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Wind Zone
The HUD design wind speed region a manufactured home was built for, under 24 CFR § 3280.305 — Zone I inland, Zone II at 100 mph, Zone III at 110 mph.
Why it matters: It determines the anchoring and tie-down specification. Two identical homes in different zones require different anchoring, so a tie-down schedule copied between markets is wrong in one of them.
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