A tiny home on wheels sits a foot or two off the ground, and in winter that gap becomes a wind tunnel. Cold air rushes under the floor, chills the pipes, and turns the floor into a cold slab no rug can fix. Skirting — a barrier that closes the gap between the bottom of the home and the ground — is the single most effective winter upgrade for a raised tiny home, and it costs far less than the burst pipe it prevents. Here is how skirting works, what to make it from, and the ventilation mistake that ruins an otherwise good job.

Why the Gap Under Your Home Costs You Heat

Heat loss through an unskirted floor is surprisingly large. An exposed underbelly lets wind strip heat from the floor, the water lines, and the holding tanks all at once, and a furnace or heater has to work harder to replace it. Owners who skirt for the first time often report the floor feeling several degrees warmer and the heater cycling less often, which shows up directly in propane or electricity use. The pipes matter more than the comfort: a water line exposed to moving sub-freezing air can freeze overnight, and a burst pipe inside a tiny wall cavity is a miserable repair in January.

Skirting works by creating a dead-air space under the home. Still air is a poor conductor of heat, so once the wind is blocked, the ground itself — which stays well above freezing a few feet down — warms the enclosed space. Even uninsulated skirting makes a large difference; insulated skirting makes a bigger one. The key is a complete seal: a gap of even a few inches at a corner lets wind in and defeats much of the benefit.

Materials: What to Use and What to Avoid

The most common choice is rigid foam board, usually two-inch XPS or polyiso, cut to fit and held by a simple frame or adhesive. Foam insulates as well as it blocks wind, it is light enough to handle alone, and it can be removed and reused each spring. Plywood is cheaper and tougher, but it insulates poorly and needs paint or sealant to survive a wet winter. Vinyl skirting kits made for mobile homes are quick to install and look tidy, but they are thin and offer almost no insulation on their own — they work best with foam board behind them.

Whatever you choose, protect the bottom edge. Foam board at ground level will wick moisture and get chewed by rodents, so bury the bottom inch in a shallow gravel trench or cover it with a strip of metal flashing. Avoid using loose straw bales as skirting: they insulate well, but they hold moisture against the structure and attract mice, and many insurers and fire codes dislike them. If you want a natural look, build a simple wood frame and clad it with cement board or corrugated metal instead.

Ventilation: The Mistake That Causes Mold

The most common skirting mistake is sealing the space completely airtight. A sealed underbelly traps moisture from the ground, and that moisture condenses on cold pipes and joists, feeding mold and rot all winter. The fix is simple: install two or three small vents on opposite sides of the skirting, and open them on dry days. In very cold weather, close them during the coldest nights and open them again when temperatures rise above freezing.

Add a layer of heavy plastic sheeting on the ground under the home before you skirt, to cut ground moisture at the source. Check the space once a month through the winter: look for standing water, drooping insulation, and any sign of animals nesting. A quick check takes ten minutes and catches problems while they are still cheap. When spring arrives, remove the skirting, let the space dry out fully, and store the panels flat so they are ready for next year.

Skirting is not glamorous, but it is the cheapest winter insurance a tiny home owner can buy. Seal the gap, ventilate the space, and your pipes — and your feet — will thank you all winter.