Reflectix on underside of subfloor?

[62rosie]

Anyone see any issues with putting Reflectix on the underside of the sub floor and bolting down the panels. I did this on the first sheet, then metal taped the edges. My therory with taping the edges is that's where most of the moisture issues would be so it should help. It looks great and should make a good thermal brake etc. My only concern is am I going to trap moisture and cause and issue down the road? Plywood is marine grade treated with penetrating epoxy on all sides.

[skyguyscott]

So reflectix isn’t a very good thermal insulator. But it does a pretty good job of reflecting radiant heat as long as there is a gap between the reflectix and the surface it is shielding.

I think the best insulator under the floor would be a good spray foam. The newer formulations do not turn to dust bouncing down the road like the old ones did. Airstream did this on some model years back in the past, and I have seen pictures of the subfloor on the underside looking pristine after the foam was scraped off.

[kidjedi]

With both the reflectix and the tape, you will likely be just creating potential moisture issues. Also, putting reflectix between the frame and subfloor will allow motion and create squeaks!


If you've epoxied the subfloor, especially the edges, you should be good.


The best insulation for underneath is 2" PIC (you can get it at Lowe's/HD) with an air gap between the panel and subfloor. It does not hold water and has the best R value and lowest weight of readily available insulation materials.

[cwf]

I respectfully disagree with your idea because:
- traps moisture (there will always be some)
- moisture = mold = rot = metal rust, etc

Same with spray foam. When plywood floor gets water in it, there must be a way for it to get out... vibration on the road may cause delamination. I would not want to lay under the AS to spray the foam... and you do not want to spray inside the belly pan....rust, etc

Part of why AS uses the pink stuff. Gets wet, lots of airspace so dries quick..

Just thoughts...

[SuperTrouper]

Hi 62Rosie!

If you read through this thread you'll see the problems I had with reflectix (factory installed). Given that my model 27FB had water ingress issues but the reflectix trapped the water. https://www.airforums.com/forums/f39...ml#post1262866

Further down in the thread you'll see that I used extruded insulation 1/2" away from the floor to allow for some air movement. https://www.airforums.com/forums/f39...ml#post1271268

We don't camp in cold climates but have not noticed a cold floor in the rear of the trailer after the update.

Good luck with your repair/renovation of the Caravel. - Brad

[kidjedi]

Originally Posted by cwf

Part of why AS uses the pink stuff. Gets wet, lots of airspace so dries quick..

FWIW, I would say that "the pink stuff" definitely does not dry quickly. That's why the polyisocyanurate panels are so great. I've submerged it in water for more than a year (seriously), and it's back to completely devoid of water (as indicated by weight) in less than ten minutes.

[62rosie]

Well it looked nice, but you folks have confirmed my fears. Besides it will be easier. After I finish my plumbing layout, I'll remove the reflexive. I do think I will wrap the in floor gray tanks that I'm adding as they will have nothing. Thanks folks!