A Quarter Inch Of Flex Means Wet Lauan

Everybody describes this as a soft spot, which makes it sound like a judgement. It is a deflection and it can be measured with a straightedge and a ruler in about a minute. Lay a metre rule flat across the suspect area, put your weight on the centre with one foot, and measure the gap that opens between the rule and the floor at each end. A quarter of an inch of movement across that span is a great deal on a floor built as a rigid panel.

The comparison is what makes the number mean anything, exactly as with a moisture reading. Do the same thing three feet away in the same room, on the same flooring, and the sound area will move a fraction of that or not visibly at all. A coach floor is a sandwich of plywood substrate with framing under it, and its whole job is to not deflect. Any measurable difference between two points a few feet apart on the same panel is a substrate that has changed, and substrate does not change for cosmetic reasons.

The floor at a slide opening, almost always, and for a structural reason rather than a coincidence. A slide is a hole cut through a wall, sealed around its perimeter with a wiper seal that runs across the top and down each side. Water that gets past that seal runs down inside the wall cavity, invisible from both sides, and arrives at the wall to floor joint. The floor at the sill is the lowest point of a path that started somewhere nobody looks.

The second location is the entry door threshold, for the same reason with a different geometry: a doorway is a hole with a step and a seal, and everybody's wet shoes land there. The third is under a window, particularly at the upper corners of the frame, where sealant fails first and the run comes down inside the wall. The fourth is the bathroom, where the water source is inside the coach rather than outside it and the finding has nothing to do with weather at all.

Lauan is a thin tropical plywood used as substrate in enormous quantities across the industry, and its behaviour when wet is the reason a small leak becomes a large repair. It absorbs, swells, and the glue between its plies releases, at which point the panel loses most of its stiffness and gains no strength back when it dries. A dried out sheet of delaminated lauan is not a repaired sheet. It is a sheet that has stopped getting worse.

Azdel is a composite that does not absorb water and does not lose strength when it gets wet, and a coach built with Azdel wall substrate frequently survives an event that ruined the skin over it. What that does not mean is that an Azdel coach cannot have a wet floor, because floors and walls are not always the same material and the framing under a floor is timber whichever substrate sits on top of it. Wet framing rots regardless.

Neither material is printed anywhere on the outside of a coach, and it is rarely in the paperwork an owner has. Manufacturers changed materials mid model run, so two units of the same year and brand can differ. That is why the substrate question gets answered at teardown by looking at it rather than by looking it up, and it is why an estimate written without knowing the answer is a guess about how much wall and floor has to come out.

A quarter inch of deflection is not a first season finding. Water reaching a floor and the floor losing measurable stiffness are separated by a considerable period, because plywood has to absorb, swell and release its plies before it gives up strength, and it does that slowly through a panel that is bonded on top and framed underneath. A floor that moves under your weight has generally been wet through at least one wet season and often several.

That has an uncomfortable implication on a claim, and it is better heard here than from an adjuster. Damage that developed over years is deterioration whatever eventually revealed it, and a carrier declining that is applying a policy rather than avoiding one. Where an impact opened a seal path and water followed, the sequence matters and it is arguable. Where a seal simply wore out and nobody checked it, the honest answer is that the floor is a repair rather than a claim, and this shop will say so before writing something that a reinspection will find.

The corollary is more useful. A floor that has not yet begun to flex, in a coach where a meter shows a wet reading at the sill, is a coach caught early, and early is the only variable an owner controls in this entire subject. Nothing about the check requires tools, expertise or a shop visit. It requires somebody standing in their own coach twice a year and shifting their weight in four specific places.

The scope is decided by extent, and extent is decided by how far the water travelled along the framing. A localised section at one slide sill, caught with the flooring still sound around it, means lifting the finish floor over a limited area, cutting out the compromised substrate back to sound material, treating and replacing framing where it has gone, laying new substrate and re finishing. Flooring and subfloor replacement runs $500 to $8,500 and water damage restoration with subfloor work runs $750 to $15,000 or more.

What pushes a job toward the top of those bands is rarely the floor by itself. It is what the floor is attached to. A wall to floor joint that has been wet is a structural joint, and the bottom rail of the wall frame above it is timber sitting in the same water. Once that rail has gone, the wall comes down to reach it, and a floor repair has become a wall repair with a floor underneath. That is the single largest step change in this whole area and it is invisible until the finish floor comes up.

The version of this repair that costs the least is a seal. Slide out seal replacement runs $400 to $3,000, and on a coach where a wiper seal has hardened and started letting water down the wall, replacing it before anything downstream gets wet is the entire fix. Nobody books that job, because a hardened seal produces no symptom an owner notices. The symptom appears two seasons later as a floor that moves, and by then the seal is the cheapest line on a much longer document.

That is the unflattering shape of this trade and it is worth stating rather than dressing up. This shop earns considerably more from the floor than it would have earned from the seal, and the owners who spend the least here are the ones who never needed us for anything structural. Sealant inspection on a six month cycle and a seal replaced on condition rather than on failure is the version of RV ownership that costs least, and it involves this building only briefly.

Absence of deflection is not a clean result, it is one negative in a short sequence. Take a moisture reading at the sill, at the door threshold and under each window, with a control on the same wall at the same height away from any penetration. Look at the seals: a wiper seal that has gone hard, shiny or cracked is a seal at the end of its life whatever the floor is doing. Check whether the room sits square in its opening, because a slide slightly out of square opens the seal path along one edge and no seal fixes geometry.

Then look at the joint from outside. The bottom seam where the sidewall meets the floor is a sealed joint with a service life, and on a coach parked at the coast it is working against salt as well as water. Sealant that has shrunk away from one side of the joint, or that has a hairline separation running along it, is the future version of everything described above. Repairing a joint is a small job. Repairing what a joint let in for three seasons is not.