Reflectix and water?

[zen_stream]

Sorry if this is badly worded.

I'm about to start insulating my trailer. I'm using a layer of relfectix with air gap and rockwool for the rest. Pretty classic combo I've seen on the forums.

In regards to the reflectix, I know there needs to be some sort of air gap and I also see that there needs to be almost no "air movement" within the air gap "pocket", meaning that it's sort of sealed... right?

What happens if a seam or rivet covered by this air gap starts leaking? In the event a leak happens I would imagine water would fill the "air gap pocket" if the water had no place to drain out. This is a terrifying prospect.

So when I'm putting the reflectix in should I make sure that I don't cover up seams and rivet lines so water doesn't have a chance to get trapped in there?

Just to be clear I've done everything I can to prevent a future leak, I re-bucked bad rivets and bad seams and sealed with trempro 635. Not too worried at the moment, trailers very dry, just thinking of future leak mitigation.

[zen_stream]

Getting crickets here... nobody who's used relfectix has any advise?

[OTRA15]

You might want to check these "Reflectix" search results for folks using the product:

https://www.google.com/search?q=Refl...=airforums.com

On-topic replies to new threads often take time IMO.

Personally, because Reflectix does not absorb water [right?], I would not worry about this much.

Good luck,

[Bubba L]

Zen, many have gone down this road. Good, bad or indifferent, we did too. We are happy with the results. We used Prodex which is more expensive, but I think a more superior product and r-value. I think what you’re doing is good, a dead air space, and if that fails you still have rock wool insulation. On our 55, we sprayed the inside of the exterior skin with 3M spray adhesive. We stuck the Prodex and ran the wiring. Then, I cut some 3/4” x 1” strips of Foamular as a spacer. Then used double stick tape on the Foamular and stuck the interior layer of Prodex. We tried to tape/seal and cover all metal surfaces and seams to lessen thermal transfer. We, as you, put forth extra effort to make sure all exterior seams were sealed using Captain Tolley’s, Tempro and Parbond. If moisture finds its way into your wall, I think it will find its way out regardless of how well you sealed the inside and out. I think there’s just so much you can do with an 1 1/2” cavity. We tried to install a stronger than average HVAC system to help with any insulation shortfalls. Good luck

[zen_stream]

Thanks all! Ive got to start this project today so I'm trying to glean as much info as I can. Appreciate the replies.

I guess what I'm worried about is not the reflectix itself absorbing water. Im worried that If I create these "dead air pockets" that the water could collect within them in between the outer skin and the layer of reflectix.

I read a horror story about someone who didn't seal up their trailer well enough. They pulled interior walls after finding leaks. The relfectix layer was holding water like a sack because they taped it off so well. They had to stab them open to drain them. That sounds terrible. I just want to avoid that. haha

When you did your Prodex layer did you make sure there was a way for the water to escape at the bottom of the walls at the C channel? Or, as you said, does it even matter? Maybe it's impossible to tape it will enough to make it water tight? But would that be an effective dead air space? Im full of questions. It's my nature.

[Bubba L]

I may have installed some small weep holes in the C-channel, don’t exactly remember. You could drill a 3/8” hole through the channel and subfloor between each rib and caulk down a small piece of screen for ants. I think no matter how well you try to create dead air space, water is still going to find a way to migrate down the sides. As you said, stopping water from entering the cavity to begin with is paramount. At least you’re thinking ahead and outside the box.

[zen_stream]

So I'm at the big box store. Looking at the fomular that you mentioned. All I can find is 1” thick, I'm looking for 3/4”. Also it states that it shouldn't be used against a surface that exceeds 160 degrees. Will the inside surface of the outer skins be to hot to use this? Will it melt? I know you used it so it should be good. They also have 3/4” R tech. Seems to have a slightly higher max operation temp. Would that be ok to use?

[zen_stream]

Well I just grabbed the Rtech anyway. I'll do some more research. Was funny when I walked the 4*8 panel to my truck and it turned into a sail in the wind. Took off halfway across the home depot parking lot. Oops...

[Bubba L]

I didn’t use the Foamular directly against the outside skin. The Prodex was against the outside skin. I used strips of the foam as a spacer to form the dead air space. I conducted a fire test with the Prodex and it protected wood well. I did use panels of 3” thick Foamular for the belly pan insulation. That thickness was from a friend that builds commercial freezers and that’s what they sometimes use for wall insulation. I glued Prodex between the belly pan foam and the bottom of the wood subfloor, hence the fire test. There are countless ways to achieve what you’re trying to do. Research and do what you feel safe and most comfortable with to get to your goal.

[zen_stream]

Here. This photo I found from an old forum will illustrate what Im referring to a bit better. That foam board they cut into strips, can anybody identify what that is?

I just want to make sure I'm using the right material. Since it's right up against the outer skins I need to make sure it's good enough to take the heat of the skins in full sun. Worried my r-tech I bought might melt or something? I dunno.

[57Vintage]

I did the drain hole through the channel and added 1" screened louvers to the belly pan to allow for drainage. Probably overkill, but it was a challenge to sort out where to place drain holes between each wall rib and louvers in each section of the belly pan that is closed off with outriggers/frame rails. (see page 1 post 8 in our thread for more details)



(2nd photo frame upside down - ignore large circle its about a different topic)



My focus was to divert water away from the interior/sub-floor. This requires the interior wall panels to be trimmed on the bottom so they sit inside the channel. Also, make sure the louvers are aimed to the rear so they don't act as water scoops going down the road.