Waterfront house with a screened porch and dock in soft morning light after overnight rain

Field note · Rooms · 2026-10-02

The Lanai Cushions Sat Out All Night

Reed Lang, Field editor

HumidityRoomsMetersStorms Rooms

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The hallway said the house was fine. You walked out to the lanai with coffee and the cushions were cool and heavy. October on the coast is still hurricane season through the end of November. A quieter radar does not wring a sofa that sat in the open all night. The coil sees return air. The lanai sees the band and the dock. Fabric holds the rest.

Why the cushions outrank the setpoint

A screened lanai is not leftover living room. Mesh keeps bugs off the coffee. It does not keep vapor off the foam. Outdoor relative humidity (RH) after an overnight coastal band often stays in the 80s even when the morning feels “cooler” than August. Leave the cushions on the frame and they store that load. Sit on them at 8 a.m. and you put it back on your clothes, then on the hall floor when you walk in.

Living-space target on this site is about 45–55% relative humidity (RH). Sustained above 60% is the action cue. The lanai will miss that target on purpose. It is outside the envelope. The mistake is treating the cushions as if they already dried because the thermostat in the hall looks calm.

Guide: Florida humidity home guide. How to read the meter: hygrometer placement. Coastal envelope: coastal houses. This note is the open lanai on the second of October, not a second write-up of the attached glass room.

We already logged the house after the radar clears: relative humidity (RH) after overnight rain. That note is indoor air. The screened room people sit in after a September shower is the cousin: the Florida room held afternoon rain. Beads on the slider are a third problem: the slider wept after the morning band. A heavy cushion is not a puddle, and it is not the hallway.

A Florida coil wrings water when it stays on. A lanai frame never sees that coil. Crack the slider to air the porch and you import the band you just waited out. If the track looks stained, pin it against a known-dry closet. Looking dry is not a reading. Moisture meter after a leak.

Morning check (ten minutes)

You do not need a lab. You need two numbers and a hand on the cushion.

  1. Interior hallway wall. Not on the supply. Not taped to the return grille. Not in the sun on the sill.
  2. Lanai, at cushion height, shaded by the roof. Not on the screen mesh. Not in a wet cupholder. Not in direct sun on the dock rail.

Read relative humidity (RH) in both twenty minutes after you wake, then again with the slider the way you actually leave it overnight. If the lanai sits well above the hall — and it will — that gap is the point. Log both for 24 hours. A one-look display while the unit is still running off the morning bump is a lie about the house, and it says nothing about foam that never came inside.

Feel the cushion against the frame. If the board side is cool and a little heavy, you stored vapor the coil never saw. Stand the cushions on edge under the roof, off the frame, until they feel like the hall throw. Do not drag them onto the living-room sofa to “finish drying.” Do not air the lanai by cracking the slider onto a wet Thursday.

A logger on the frame beats a guess from the dock. I use a small USA-built disc for this because it sits on the rail and keeps the night, not because a brand paid for the sentence.

FloridaDamp is an Amazon associate — we earn from qualifying purchases. I still point at this one because it logs the lanai overnight without a hose or a bucket, not because anyone paid for a review.

Do not

  • Do not call the lanai dry because the hallway is under 55% relative humidity (RH). Different air. Different surfaces.
  • Do not leave soaked cushions on the frame and hope the afternoon sun is a machine. Sun warms foam. It does not replace a reading.
  • Do not crack the slider to dump porch air into the hall while outdoor relative humidity (RH) stays in the 80s. You import the load you are trying to keep out.
  • Do not run a box fan at the mesh and call it a dry-out. A fan moves wet air toward the track and the rug.
  • Do not drop the whole-house thermostat to chase one porch. Cold hallway air is not dry lanai air. We already covered the clammy trick: why 68 still felt clammy.
  • Do not park a living-room machine on the dock and expect the house coil to catch up. Size the zone you actually condition. AC versus a dehumidifier. How to measure the house. Runtime still matters inside: right-size the AC, then wring humidity.

Run this

  1. Log lanai relative humidity (RH) against an interior hallway wall for 24 hours at a normal living-room setpoint (74–76°F is a common Florida comfort band). Leave the slider the way you actually live with it after the band.
  2. If the cushions are heavy and the lanai holds well above 60% twenty minutes after the rain stops, stand them up under the roof, keep the slider shut until the hall is the drier room, and do not store beach towels in the same pile. The conditioned rooms still follow the size guide. After a rain pulse: after-storm sizing.
  3. If you dry the cushions with a machine, put that machine where it can empty without a bucket you forget. Hose downhill if you have the fall. A bucket behind the wicker is how you find a ring on the tile in October.

If landfall week is still on the calendar, stage before the cone: hurricane season moisture. If the assembly is already wet: post-storm dry-out. Cushions come inside before the mesh does.

October is not the dry season. The first milder morning is still a wet porch. Measure the lanai. Leave the wet foam outside the hall. Drain whatever you run, continuously.

Reed Lang is the field editor at FloridaDamp. Notes use published specs and common Florida rooms. Not a licensed contractor.

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