Mobile RV Subfloor Replacement Across Florida

Confirming Replacement Is Needed Over Dry-Out

The diagnostic test is simple and definitive: press firmly on the floor with your foot or a probe in the suspect area. Dry structural luan deflects very slightly and springs back. Wet but still intact luan deflects more noticeably. Delaminated, compromised luan compresses softly under pressure and does not spring back - the plies have separated and there is no structural cross-lamination left to resist the load. That soft, non-returning deflection is the signal that drying will not restore integrity and replacement is the correct repair.

A pinless moisture meter reading above 25 to 30 percent in a floor section, combined with the soft deflection test, is sufficient confirmation. We do both tests because high moisture readings alone, without the structural deflection, can indicate a section that is wet but not yet delaminated - dry-out and monitoring is still appropriate in that case. The distinction saves owners from unnecessary replacement work on sections that can still be saved.

What Material Goes In

Standard practice for quality RV subfloor replacement is three-quarter-inch marine-grade plywood over the aluminum frame, with a six-mil polyethylene moisture barrier between the frame and the new subfloor. The moisture barrier prevents frame-transmitted humidity from wicking into the underside of the new material during Florida's humid season. Some manufacturers use luan as the replacement material to keep costs down - it is cheaper and lighter, but in Florida's environment it is a short-term answer to a problem that demands a long-term material.

In slide rooms, the replacement material is cut to fit with the room extended, since working on a retracted slide room subfloor requires either full slide disassembly or awkward access that compromises the repair quality. We extend the slide, make the repair with the room accessible, and verify travel clearances before closing the job. The slide travel test - full extension and retraction under power - is the final confirmation that the subfloor repair has not changed the slide room geometry.

The Infiltration Source Must Be Fixed First

Replacing a subfloor without addressing the source of infiltration is the most common reason we see second subfloor replacements in coaches less than five years old. The water came from somewhere - a failed roof seal, a window frame separation, a slide room topper that no longer channels water away from the seal, a cracked holding tank fitting. If that source is still active when the new subfloor goes in, the new material will follow the same trajectory as the old material, just on a slightly longer timeline.

The infiltration source investigation is part of every subfloor replacement job. We do a full pinless meter survey of the surrounding structure and roof penetrations before any floor material is removed, because the map of elevated readings tells us where the water entered and what path it took to reach the floor. Addressing the source and the damage at the same visit is more efficient than two separate service calls and produces a repair that is genuinely finished.

How Invasive the Job Actually Is

Most owners imagine subfloor replacement as a complete interior gutting. In practice, the job is far more targeted. The flooring material - typically vinyl plank or sheet vinyl - is removed from the affected section. Cabinetry that sits on the subfloor over the repair area may need to be supported or temporarily removed if it is anchored through the floor into the frame. Walls that rest on the subfloor do not need to come down - the subfloor is cut back to the nearest frame member, the damaged section is lifted, and the new material is fitted and fastened to the frame.

A typical partial subfloor replacement covering a four-by-eight section takes one full day of service. A full coach subfloor replacement - which we do see in coaches that sat with undetected water damage for multiple seasons - takes two to four days depending on coach length and the number of slide rooms involved. The scope is established after the initial assessment and confirmed before work begins.

Flooring Reinstallation After Subfloor Replacement

If the existing vinyl plank or sheet vinyl is in good condition and was installed with a floating method - snapped together or loose-laid rather than glued down - it can frequently be relaid over the new subfloor after the repair. Glued-down sheet vinyl rarely survives removal in reusable condition, and those jobs typically include new flooring as part of the total scope.

The subfloor surface needs to be flat and level within the same tolerances as original installation before flooring goes down. Any fastener heads are countersunk, seams between new and existing subfloor sections are filled and sanded, and transitions are blended so there is no ridge that would telegraph through flexible vinyl. A subfloor repair that shows through the finished floor is a quality failure, and we treat the surface prep as part of the job rather than the flooring installer's problem.

Moisture Barrier and Frame Treatment

The aluminum frame under the subfloor rarely corrodes to structural failure, but we inspect every frame member that is exposed during the repair and treat any surface corrosion with a rust converter before closing the job. Light surface oxidation is normal and does not require frame replacement. Deep pitting or sections where a frame member has been wetted repeatedly and the protective coating has failed get a coat of cold galvanizing compound before the moisture barrier and new subfloor go on.

The six-mil poly barrier is lapped up the interior of the frame channel on all four sides of the replacement section and taped at seams with butyl tape rather than standard construction tape. The goal is a continuous moisture barrier that channels any future condensation or minor infiltration toward the exterior of the coach rather than into the underside of the new material. This detail is the difference between a subfloor that lasts fifteen years and one that needs attention again in five.

Prevention Going Forward

Two practices extend subfloor life in Florida beyond the repair itself. First, the full roof and perimeter seal needs to be checked every twelve months - Florida's UV and thermal cycling degrades lap sealant on an annual cycle, and fresh sealant applied before each rainy season costs a fraction of any floor repair. Second, coaches in Florida storage should be parked with adequate roof ventilation active and inspected before each season rather than assumed to be in the same condition as when stored.

Jesse Marcer and the Triton RV Repair team have been performing subfloor replacements across Florida since 2014, with RVIA certification and the mobile equipment to complete most jobs at the coach's location without towing to a shop. We carry marine-grade plywood, moisture barrier, and standard vinyl plank flooring on the service truck to minimize the time between diagnosis and completed repair.

Questions we get on this service

Sources

• Lippert RV floor construction documentation - Subfloor thickness specifications, moisture barrier requirements, and frame attachment details.