Buyer's guide

LVP in Florida heat and humidity

Humidity is not what moves a stone-core plank; heat is. Acclimation, expansion gaps, slab moisture and the warranty exclusions that actually bite.

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The short answer

Rigid-core SPC barely moves with humidity. Heat is what moves it. Acclimate the boxes 48 hours in the room they will be installed in, keep the house conditioned before, during and after the install, leave the expansion gap on the floor's installation sheet at every wall and fixed object, and break long runs with a T-mold. Every one of the 77 floors we stock is a stone-plastic core with an attached pad; none is wood-based, and none absorbs moisture.

Condition	What happens to the floor	What to do
Normal Florida humidity, conditioned house	Nothing measurable. SPC does not take on moisture	Install to the sheet and forget it
Room heats in afternoon sun (sliders, sunroom, lanai)	Planks expand, and a run with no room to grow peaks at a wall	Full expansion gap, SPC not WPC, blinds on the glass, T-mold on long runs
House left unconditioned for weeks	Temperature swings past the sheet's range; joints can open or peak	Keep the thermostat running in an empty house, especially a vacant unit or a seasonal home
Damp slab	The plank is unaffected; the pad, adhesive and anything organic under it are not	Test the slab before ordering; treat it if it fails
Storm season power loss	A few days is fine; weeks of heat and humidity in a closed house are not	Ventilate when it is safe to; restore cooling before it becomes a mold problem
New construction, slab under 60 days old	The slab is still releasing water	Wait, or test and treat

How we know: these figures are read from the 77 floors stocked in our distribution partners' Jacksonville, Miami and Orlando warehouses as this page was built, not from a manufacturer brochure. Prices are the per-square-foot rates published on each floor page.

Does humidity make LVP expand?

Vinyl with a stone-filled core does not absorb water, so humidity on its own does almost nothing to it. The floors that swell in Florida humidity are the wood-based ones: laminate, engineered wood, and older wood-plastic vinyl with a foamed core. What does move any vinyl plank is temperature. Plastics expand as they warm, the printed design and wear layer expand with them, and a room that runs 20 degrees hotter than the rest of the house in the afternoon is asking every plank in it to grow at once. That is why the guidance below is about heat, gaps and conditioning rather than dehumidifiers.

How long should LVP acclimate in Florida?

48 hours is the figure on most rigid-core installation sheets, in the room where the floor is going in, with the house at the temperature it will be lived in. The boxes lie flat, off the slab, unopened or with the ends opened, and not stacked against an exterior wall in the sun. A garage does not count: it is the one space in the house that is not conditioned, and planks that acclimate at 95 degrees and go down in a 76 degree room will shrink and open at the joints. Delivery is curbside, so plan the two days between the truck and the crew.

What expansion gap, and where?

The installation sheet for the specific floor gives the number; for rigid-core click planks it is typically 1/4 to 3/8 of an inch at every wall, cabinet base, pipe, door frame and fixed object, covered by base molding or quarter round that is nailed to the wall and never to the floor. The gap is not optional in a room that gets sun. The second rule is run length: sheets set a maximum continuous run in each direction, after which a T-mold splits the field so each section can move on its own. 77 of our 77 floors have a matching T-mold in stock. Kitchen islands and vanities that sit on top of the planks pin the floor and defeat both rules; the floor should stop at them with a gap, not run under them.

Does an SPC floor need a vapor barrier on a slab?

The plank does not, and the attached IXPE pad on all 77 of our floors is closed-cell. The reason to care about slab moisture is what lives under the floor: trapped moisture between a damp slab and a waterproof plank has nowhere to go, and the result is a musty room, not a swollen plank. Rigid-core sheets typically set a limit on slab moisture, expressed as relative humidity in the slab or as a calcium chloride emission rate. A slab that has been dry and covered for years usually passes; a new pour, a slab that had carpet pulled up and smelled of it, or a room with a history of standing water should be tested. Treatments range from a topical sealer to a full epoxy moisture barrier, and the test tells you which.

What voids the warranty?

Every floor we stock carries a 30-year residential and 10-year commercial warranty, and the exclusions are nearly identical across rigid-core makers: installation outside the sheet's temperature range or in an unconditioned space, no expansion gap or a run past the maximum length, a second underlayment under the attached pad, cabinets or islands installed on top of a floating floor, and a subfloor that was not flat or was wet. None of those is about humidity in the air. All of them are about heat, room to move, and what is under the plank.

Rooms that get hot deserve the stiffest plank: the 8 mm tier at $2.49 per square foot moves least and hides the most. See the SPC versus WPC guide for why a stone core is the one to use in a sunroom.

Common questions

Can I install LVP in a screened lanai?

Only if it is conditioned or the installation sheet's temperature range is never exceeded, which a screened, unconditioned lanai in August will not satisfy. Most rigid-core warranties exclude it.

Does LVP need to acclimate if it was stored in the same city?

Yes. The point is the room's temperature, not the city's. A warehouse or a truck is not the room.

Should I run a dehumidifier before installing?

For SPC, no. Run the air conditioning to the temperature the house will live at; that does more for the floor than lowering humidity does.

What happens to the floor if the power is out for a week after a storm?

The planks will be fine. Open the house when it is safe and get cooling back before mold has a chance under furniture and rugs. Check that no plank has peaked at a wall and, if one has, that the gap is still there.