Underpinning a camper means creating a stable, long-term support system underneath it and then enclosing that space to protect against weather, pests, and heat loss. Whether you’re setting up on a seasonal lot or parking semi-permanently, the process involves preparing the ground, leveling and supporting the frame, anchoring against wind, and skirting the perimeter. Each step matters, and cutting corners on any one of them leads to problems down the road.
Prepare the Ground First
Everything you build sits on the soil, so this step determines whether your camper stays level or slowly sinks and shifts over the coming months. Start by clearing all vegetation, roots, and debris from the area where the camper will sit, extending at least two feet beyond the camper’s footprint on all sides. Grass and organic material decompose over time, creating soft spots that compress unevenly under load.
Once the ground is cleared, you need to compact the soil. Compaction presses soil particles together, eliminates air pockets, and increases the ground’s ability to bear weight without settling. For a camper pad, a handheld vibratory plate compactor (available at most equipment rental shops) works well on sandy or granular soils. Clay soils are trickier and may need moisture adjustment before compacting: too wet and the soil turns slippery, too dry and it won’t hold together. You want soil that clumps in your hand without dripping water.
If your native soil is soft or poorly draining, adding a layer of compacted gravel on top gives you a firmer, more stable base. A four-to-six-inch layer of crushed stone, compacted in two-inch lifts, provides excellent drainage and load distribution. This is especially important in areas with heavy rainfall, where water pooling under the camper accelerates rust and undermines your supports.
Level the Camper Correctly
Leveling and stabilizing are two separate jobs, and confusing them is one of the most common mistakes. Leveling means getting the camper flat so doors close properly, appliances work correctly, and water drains where it should. Stabilizing means keeping it from rocking once it’s level. Your stabilizer jacks are not designed to lift or level the camper. They’re only meant to reduce movement after the camper is already sitting flat.
For side-to-side leveling, manufactured plastic leveling blocks (stackable ramps or interlocking blocks) are far more reliable than scrap lumber. Wood splits, rots, and compresses unevenly over time. Plastic leveling blocks are durable, store easily, and distribute weight more consistently. Drive or position the camper onto the blocks on the low side until a bubble level reads flat. Then use the tongue jack to level front to back, which is typically a quicker adjustment.
Choose Your Support Method
For a camper that will stay in one place for months or years, the factory scissor jacks alone aren’t enough. They’re designed for weekend camping, not long-term static support. You have three main options, each with tradeoffs.
Concrete Blocks or Piers
Stacked concrete blocks (CMU blocks, not decorative landscaping blocks) are the most common choice for semi-permanent setups. They’re cheap, widely available, and strong in compression. Stack them in a pyramid pattern with the hollow cores aligned vertically, and place a solid cap block or a piece of 3/4-inch plywood on top to spread the load across the camper’s frame rails. The key is placing them directly under the main chassis rails, not under the floor or sidewalls. One experienced owner’s approach: set the rear blocks first with the camper slightly below level, then set the front blocks with it slightly above level, and lower back down until weight distributes evenly between all contact points.
Heavy-Duty Jack Stands
Steel jack stands from a tool supplier offer the advantage of fine-tuned height adjustment, which matters if the ground settles over time. Jack stands are rated by what a pair can support together, so a “2-ton” pair handles up to one ton per stand. For a camper, you want stands rated well above your actual load. A typical travel trailer weighs 4,000 to 8,000 pounds, so four 3-ton stands provide a comfortable safety margin. Place them on flat steel plates or concrete pavers to prevent them from sinking into the ground. Jack stands are rated for static loads only, meaning sudden jolts from high wind or someone jumping inside could compromise them if they’re the sole support.
Combining Both
Many long-term setups use concrete block stacks as the primary weight-bearing supports with adjustable jack stands as secondary stabilizers. This gives you the permanence of masonry with the adjustability of steel. You can fine-tune the jacks seasonally as the ground shifts with freeze-thaw cycles or dry-wet conditions.
Account for Frost Depth
If you’re in a climate where the ground freezes, frost heave can push your supports upward and tilt the entire camper. The frost line, the depth to which soil freezes in winter, varies dramatically by region. In south Florida it’s essentially zero. In Minnesota or northern Canada, it can exceed eight feet. Most of the northern United States falls somewhere between 36 and 60 inches.
For concrete pier supports, the bottom of the pier should sit at least a few inches below your local frost depth. Digging three to four inches deeper than the published frost line gives you a buffer. Your local building department can tell you the exact frost depth for your area. If you’re placing blocks on the surface in a freezing climate, expect to re-level the camper at least once a year as the ground moves. Surface supports work fine in mild climates but become a recurring maintenance headache where winters are harsh.
Anchor Against Wind
A camper sitting on blocks or jacks with no tie-downs is vulnerable to strong winds. This is especially critical in hurricane-prone or tornado-prone regions, but even moderate storms can shift an unsecured camper. The standard for mobile home anchoring systems requires each anchor to resist a working load of at least 3,150 pounds, with the entire system certified to handle a 50 percent overload of 4,725 pounds.
The type of anchor depends on your soil. Auger anchors screw into the ground and come in versions for both hard and soft soil. Rock anchors or drive anchors work for rocky or coral ground. If you’re pouring a concrete slab or piers, you can embed concrete anchors before the pour. Straps or cables run from the anchors over the camper’s frame or chassis, secured with turnbuckles that let you adjust tension. When tightening, alternate from side to side rather than doing one entire side first. This keeps the load balanced and prevents the camper from shifting during installation.
Install Skirting for Weather Protection
Once the camper is level, supported, and anchored, enclosing the underside with skirting keeps out wind, animals, and cold air. But not all skirting materials perform equally when it comes to insulation.
Vinyl skirting is the most popular option. It’s affordable, easy to install with a track system screwed to the camper’s bottom rail, and holds up reasonably well against UV exposure and moisture. However, standard vinyl provides almost no insulation value. Even vinyl skirting marketed as “insulated” typically contains less than half an inch of sewn-in filler like poly-fill or reflective bubble wrap, which adds very little thermal resistance. In moderate climates where you just want to block wind and critters, vinyl alone is fine.
For cold climates, rigid foam board is the real performer. Extruded polystyrene foam board, sold as blue or pink board at hardware stores, delivers roughly R-5 per inch of thickness. A two-inch layer gives you R-10, which is meaningful protection for pipes and tanks underneath. To match that with sewn-in skirting insulation, you’d need material four to five inches thick. The most effective cold-climate setup combines an outer layer of vinyl or similar skirting with an inner layer of rigid foam board. The vinyl handles weather and appearance while the foam does the actual insulating.
Whichever material you choose, leave a small gap or vent on at least two sides of the skirting. Completely sealing the underside traps moisture, which accelerates frame corrosion. You want enough airflow to prevent condensation without letting frigid wind blow directly on pipes.
Protect the Frame From Corrosion
Enclosing the underside of a camper changes the moisture dynamics around the steel frame. Without skirting, the frame dries out naturally from air circulation. With skirting, moisture from the ground, condensation, and any small leaks lingers longer. Before you close everything up, inspect the frame carefully for existing rust and treat any problem areas.
A wax-based or lanolin-based rust prevention coating applied to the entire frame creates a barrier against moisture. These products stay slightly tacky and self-heal over minor scratches, unlike paint which chips and then traps moisture underneath. Apply the coating generously to all frame members, cross-members, and any exposed metal hardware. Reapply every one to two years by removing a section of skirting and spraying the underside.
Laying a ground vapor barrier (6-mil polyethylene sheeting) on the soil under the camper before installing skirting dramatically reduces the moisture that rises from the ground into the enclosed space. Overlap the sheets by at least 12 inches and extend them to the skirting edges. This single step does more to prevent corrosion than any frame coating.
Check and Adjust Seasonally
Even a well-done underpinning setup needs periodic attention. Walk the perimeter every few months and check that skirting panels are intact and secure. Look under the camper for signs of moisture pooling, animal intrusion, or supports that have shifted. Re-level the camper if doors start sticking or you notice water pooling on countertops or in the shower. In freeze-thaw climates, spring is the most common time for re-leveling as the ground settles after winter heaving. Tighten tie-down turnbuckles if straps have loosened, and inspect anchors for any signs of pulling out of the ground.