reflectix question

[dogear52]

I have to get my CT ready to roll by end of April on the cheap for now. Rather than using polyiso throughout, could I put reflectix on the outside of the 1/2 plywood walls (gives me 1" dead air space) to repel the outside heat? I'll be putting 1/2" polyiso on the ceiling foil side up, a Maxx fan in ceiling vent, and installing floor vents. I do plan to stay in higher elevations during summer starting with Sedona, Flagstaff area and I do fine in dry 90s heat.

 

[GotSmart]

Floor vents. Hard to keep them from letting in critters, dust, and exhaust gasses.

 

[dogear52]

Hmm....good point. Will reconsider that idea.

 

[Almost There]

If you want floor vents that can be closed watertight while driving, take a look at marine equipment.

They can be installed with noseuum mesh or window screen to prevent critters and bug entry.

Here's the type of thing I am thinking of.

http://guide.alibaba.com/shop/perko-1313dp0chr-marine-fuel-deck-fill_9892718.html

 

[WheelEstate USA]

So, you didn't insulate behind the plywood??
I don't think Reflectix will help very much against the plywood on the inside for summer...maybe a tiny bit but will  it offset the cost??? Not so sure.
It works wonders on windows, especially if there's an air space between.

I considered a floor vent but shucked the idea.

 

[CTP]

So, you didn't insulate behind the plywood??
I don't think Reflectix will help very much against the plywood on the inside for summer...maybe a tiny bit but will  it offset the cost??? Not so sure.
It works wonders on windows, especially if there's an air space between.

I considered a floor vent but shucked the idea.

You might use a house dryer vent facing to the back.  You would need to connect a wire or cable to the flap in it to keep it closed and some screen on the grate inside

 

[dogear52]

Thanks for the tip/link Almost There. Good idea....

 

[dogear52]

bindi&us, I figured if the Reflectix was facing out with a 1" air space between it and the outer skin of the trailer it would prevent a lot of outside heat from coming into the trailer. From what I read on the Reflectix site re roof and wall applications it looks like it would work. Before cold weather season hits I was planning to put 1" polyiso on the inside of the plywood with foil side facing in. The floor vents will be there to draw cooler air from underneath the CT when the fan is running but not positioned so it flows directly out.....maybe in each corner of the floor.
CTP, dryer vent is a good idea....thanks.

 

[dogear52]

Just realized this should have been posted in insulation category. How to move it?

 

[WheelEstate USA]

One of the mods can do the move.

I'm wondering....why spend time and money on Reflectix if you're going to insulate with Polyiso.

After having all our windows covered with Reflectix on cold nights I can only say its a trip being inside a foil lined box. It was better than being cold tho

 

[Almost There]

One of the mods can do the move.

I'm wondering....why spend time and money on Reflectix if you're going to insulate with Polyiso.

After having all our windows covered with Reflectix on cold nights I can only say its a trip being inside a foil lined box. It was better than being cold tho

AFAIK, they serve two different purposes, one is a radiant heat barrier (reflectix), it has very, very low insulation value. The other is insulation.

If anyone knows any different, I'd be interested in hearing it too because that was my plan for the van - air space, reflectix, air space, polyiso, then finish cover for décor because a foil lined box just isn't ME...

 

[dogear52]

I wont have the money to buy that much polyiso until I get my pension check May 1 and hit the road. When I get to AZ (Sedona area) I'll have to buy and install it when I get there but the total installation might take me into June depending on how far I can stretch a dollar. So if it's overkill in the end I should omit the reflectix and let air flow from the fan cool the CT while I install the polyiso. The ceiling should already be done before I head out.

 

[akrvbob]

Reflectix only works with an air gap and it sounds like you are putting on in so it will work okay. Personally I think you are better off with more Polyiso, but that's just my opinion. In Flagstaff it's very easy to park in the shade and heat is only a minor problem. Once the monsoons hit in late June and July heat isn't really an issue.

No floor vents for me.
Bob

 

[compassrose]

...  I'll be putting 1/2" polyiso on the ceiling foil side up...

You have your polyiso backwards. The foil heat barrier should face your interior.

My suggestion: Use 1" polyiso on the ceiling. Coat your roof (may require sanding) with a reflective roof coating (I used SolarFlex and the difference is amazing). Furr out your sidewalls using furring strips the thickness of your planned insulation then screw the plywood into the furring strips leaving dead air space. Then as you can, add the polyiso insulation. Unscrew plywood, add insulation, screw plywood back on. Bear in mind that the polyiso insulation is the thickness that it is listed as whereas wood products are not. Typically 1" nominal thickness wood = 3/4" actual thickness. What this does is give you a thermal break (very important). Also Reflectix is a heat barrier NOT an insulation. It does a good job of "reflecting" heat but not so good of a job reflecting the cold. It also ain't cheap. Take your money that you were going to invest in Reflectix and buy polyiso insulation instead. Even batt insulation would be a better buy.

Roof first, then walls, then floor.

 

[gramakittycat]

Okay so I have Reflectix I plan on using to cover the windows of my minivan to keep the interior cooler during summer.Foilside in or out, and place it flush against the glass?

 

[compassrose]

For windows, foil out towards glass to reflect the exterior heat gain you get thru glass. With glass, you are simply trying to reflect the passive heat gain. If you want some light, use clear bubble wrap instead. It does about the same as Reflectix.

I have found the best thing for glass (if you aren't going to make interior storm windows) is clear bubble wrap stuck on all window glass in winter, removable Reflectix placed OVER the clear bubble wrap, in summer or on very cold winter nights, makes the best solution. I have used the foil/foil sided Reflectix and the black/foil sided Reflectix (heard about the white/foil but never seen any). I would opt for foil facing outward on Reflectix particularly in summer. If you are in triple digit summer heat (like I am), stick the Reflectix over the clear bubble wrap. Make sure you are covering the metal frame of your windows if you have them.

By keeping the Reflectix removable, you can pull them down to let a little natural light in if you want or put them up, particularly in the late afternoon to cut the late sun or at night to hide your interior lights.

For my use, I cover the Reflectix with a thick oversized bath towel as a curtain so I don't see all the shiny and feel like I'm living in a sci-fi movie.

 

[WheelEstate USA]

gramakitty...always a space behind the Reflectix. Ours is about 3/4" from the glass. Rose's idea with bblwrap takes care of that space with dead air.

I marked from outdoors using the outer edge of the window seal as a guide. It was then easy to trim for a good fit inside.
If you're going to be removing trim screws to tuck it in place you might want to go a tad large. Use an old credit card to tuck it into place.

I like that the stuff is easy to cut and work with...and it does a heck of a good job on windows.

 

[WheelEstate USA]

Rose...along with insulation in the ceiling, I put 2 coats of Henry's white on the roof.
The headliner stays pretty cool even on a hot day. Its easy to keep the interior 10 degrees cooler than outside with windows open and a fan going. Open the doors and it drops a few degrees more.
What really makes a difference is when it rains. The white softens the sound a whole bunch.

Problem with Henry's white is that it lifted some of the paint and peeled in a few places. Places where I brushed the surface rust (Az sun damage) it stuck just fine. While I'm up at Cottonwood I will re-do the top after sanding away the rest of the paint.

 

[compassrose]

I've got three coats of Henry's on my roof. Did back in 2011. I plan on recoating this fall while on the road. Possibly at my moms since there is a possibility my daughter & I will be staying there a few days. I figure I will acquire a bucket at some point during the trip or order it before I leave here. I sand blasted the roof of the bus before applying.

 

[WheelEstate USA]

Sandblast is the best way to go for something as large as your bus.