Insulation over plywood

[foxontherun]

Good afternoon all,
Aluminum cargo trailer with 1" pink foam board in walls. Seams are taped off and covered with 1/2" plywood. Would like to add additional insulation without having to remove that plywood if possible Any harm in adding additional 1" pink foam board over that to increase insulation value? Plan would be to put 1/4" luan over that for finished wall. Wondering if there might be a possible issue of trapping moisture in between the two layers where the 1/2" ply could potentially mold and rot.

I have two roof vents which i leave at least partially open all the time as well as the two side vents that came on trailer for ventilation.

Thanks,
Harry

[flboy]

I'd be concerned with the plywood getting moist in between due to condensation. I would remove the plywood and add furring strips to the existing studs, add more insulation and re-attached plywood to furring strips.

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[John61CT]

A taped plastic dropcloth liner before the final inner skin

or a good sealant caulk / paint job

providing a 100% vapour barrier

will do the job.

Seal the luan well too, fully encapsulating before installing is best, or a non-organic skin

well ventilating as well.

How anal you need to get depends on climate of course, PNW or Florida very different from Arizona.

[Tomterrific]

I'll weigh in here and agree with flboy, just remove the plywood and reinstall after the extra insulation is added. This seems to be the worry free way.

Tt

[foxontherun]

Thanks for the replies; i appreciate it. Sounds like removing the plywood is probably the best way to go as i do live in TN and most of our camping is in the southeast currently.

Harry