Can an RV garage or boat bay take the same coating as the two-car garage next to it?
Yes. An RV garage or boat bay gets the same garage floor coating as the house garage: a diamond grind, a moisture reading, a 100% solids base, a flake broadcast and a polyaspartic top coat. The build around the parked vehicle is where the bay differs, because its weight rests on a few small feet and water sits under a cover until May.
A car in a two-car garage leaves every morning, and the floor under it gets aired out and looked at every day. A boat on its trailer or a fifth wheel on its jacks parks in October and stays put. Anything that goes wrong under it goes wrong for seven months before anyone sees it.
If the bay is detached and unheated, its slab runs on the same cold-weather clock as any unheated garage in town, which the winter coating calendar lays out month by month. And if the building stores or services other people’s boats and RVs for money, it is a commercial marine and RV bay with a different spec, which is outside this guide.
What does a trailer tongue jack or an RV leveling pad do to a coated floor?
A tongue jack or a leveling jack puts a large share of the vehicle’s weight onto a foot a few inches across. The concrete carries that load fine. The risk to the coating comes from the foot itself, dropped hard or twisted while it is cranked down. A bare steel foot scratches and chips where a padded one does not.
The fix costs almost nothing. Set a pad under every foot that touches the floor. A square of plywood, a rubber jack pad or a purpose-made leveling block spreads the load and takes the grinding when the foot turns. Swivel casters on a tongue jack are harder on a floor than a flat foot, because the wheel pivots under load every time the tongue gets swung. Parking a caster on a pad for the season avoids a crescent-shaped scuff in the top coat.
Tires are the other contact point. A trailer or motorhome tire parked on one spot for months can leave a faint brown stain on some coatings as compounds in the rubber migrate into the film. Polyaspartic top coats resist that better than a plain epoxy finish, and a mat under each tire removes the question. The summer version of this problem, a boat trailer parked on a hot slab all July, is covered in the guide to studded tires, de-icer and coated floors.
What happens under a boat that sits on the floor from October to May?
Lake water keeps draining out of a boat for days after it comes off Lake Coeur d’Alene or Hayden Lake. With the drain plug pulled for winter, it drips onto one spot of the floor. Under a cover, that spot and the floor around the trailer get little air and stay damp for weeks. A sound coating is not hurt by water. A crack or a thin edge nearby is where water gets under.
The part of the floor out in the open dries in a day or two in October. The footprint under the hull does not. A cover that drapes to the floor holds the damp in, and an unheated slab in November is cold enough that the moisture condenses rather than evaporates. By spring there is often a ring of lake silt where the drip landed and a dull, filmy patch around the trailer bunks.
None of that damages a properly bonded floor. It cleans up with a hose and a deck brush. The trouble starts when the drip lands on a spot where the coating was already compromised, like a hairline crack the grind never opened or a chip from a jack foot, and water sits in it through a freeze.
The habits that help happen before the boat goes in:
- Rinse the hull and trailer on the driveway and let them drain there for an afternoon. The same clean, drain and dry routine that boat inspections ask for keeps most of the lake off the floor.
- Put a drip pan or a shallow tray under the drain plug opening for the first couple of weeks.
- Leave a gap at the bottom of the cover so air moves under the hull.
- If the boat was winterized in the bay, wipe up any antifreeze that runs out of the engine or lines. It is mild on a coating, but it stays sticky and holds grit.
Which flake broadcast and top coat thickness make sense where the load sits in one spot?
Full-coverage flake and a heavier top coat. A full broadcast builds a thicker, harder layer than a partial scatter, and the flake hides the scuffs a jack foot or a trailer tire leaves. In the parking footprint, a second pass of top coat adds wear layer where the floor takes the most abuse. That second pass is a small line on the estimate for a big bay.
A full broadcast leaves a floor of chips with sharp little edges standing up from the base. The top coat fills around them. One coat over a full broadcast still leaves the texture of the chips under your hand, and a jack foot sitting on that surface bears on the high points. A second coat fills the valleys, so the foot rests on a flat, continuous wear layer instead of on chip edges.
Where that second coat goes is worth drawing on the floor plan. Under the tongue jack, the stabilizer feet and the tires, the extra build earns its keep. Out in the middle of the bay, where nothing parks, the standard build is plenty. It also keeps the smoother, heavier finish off the path you walk around the trailer.
How much texture does a wide floor need when you walk around a wet trailer?
More than the house garage, and mostly around the edges of the parking footprint. You walk the full length of a trailer or motorhome to reach the cover straps, the hitch and the far side, often with the floor still wet from a drip or a rinse. An aggregate broadcast into the top coat along that path gives your boots grip without making the whole bay hard to sweep.
On a two-car floor you take a few steps from the car door to the house door. In a bay this size you might cover sixty feet in a lap around a boat, carrying a cover or a battery, in poor light. That walk is the reason to add texture, and the path around the stored vehicle is where it belongs. The general question of why coated floors get slick when wet has its own section in the downsides of an epoxy garage floor.
How much does coating an RV garage or boat bay floor cost?
By the square foot, with the setup spread over more floor. A full-flake garage system in Coeur d’Alene runs $7 - $10 per square foot installed, and a full professional system on a 1,000 square foot floor lands around $7,000 - $11,000. A big bay often prices at a better per-foot rate than a small garage because the crew mobilizes once for more floor.
Measure the bay wall to wall. A building 25 feet wide and 40 feet deep is 1,000 square feet, more than twice a typical two-car garage, so the per-foot rate does more of the work in the total.
The things that move the number on a big residential bay are the ones that move it on any garage. How much crack and spall repair the slab needs. Whether it meters wet. How much texture goes into the top coat, and whether the walls get a cove base. A slab poured recently for a new RV building also has its own curing questions before any coating can go down. The page on what a 1,000 square foot floor costs has the full ranges by system.
Should the RV side and the car side get the same system?
Usually yes, installed as one job. Same grind, same base, same flake blend, so the two floors match and the crew mobilizes once. The RV or boat side then gets its own details written into the estimate: the heavier top coat in the parking footprint and the texture along the walk-around path.
The exception is timing. If the car side is attached and heated and the RV bay is a detached, unheated building, the two slabs may not be ready in the same week. A late-season job can mean coating the warm side now and the cold bay in spring, or putting a one-day polyaspartic system on the cold bay so both get done before the boat comes home.
A bay that swaps tenants over the years is worth building for the hardest one. A pontoon on a bunk trailer drips from two long rails, while a travel trailer on stabilizer jacks puts its weight on four small feet and stays dry. If the next owner of the bay might park either one, ask for the heavier top coat under both the bunk line and the jack positions.