TheSamba.com :: View topic - Trying to stop heat transfer from the roof

Thu Sep 08, 2016 12:11 pm

bobbyblack wrote: I have also been wondering about this. My wish list includes solar, so I further wonder how something like this would affect the heat/radiation inward to cabin. Anyone with experience? Does the black make it hotter coming down, or does the air gap mitigate?

Excellent point. If the Safari roof could be made out of solar panels and still have the isolating function, that would be great.

Thu Sep 08, 2016 12:54 pm

OddN wrote: bobbyblack wrote: I have also been wondering about this. My wish list includes solar, so I further wonder how something like this would affect the heat/radiation inward to cabin. Anyone with experience? Does the black make it hotter coming down, or does the air gap mitigate?

[pics]

Excellent point. If the Safari roof could be made out of solar panels and still have the isolating function, that would be great.

Its kind of like parking in the shade.. 8) 8) 8)

Thu Sep 08, 2016 1:15 pm

Yea the ideal solar setup would be a portable one, one on top of the van means you have to park in the sun. but works great when driving, but parking in the shade when camping keeps everything inside cooler.

Thu Sep 08, 2016 1:15 pm

Solar parking structures are common in silicon valley. Cars are cooler and "free" electricity.

Thu Sep 08, 2016 2:01 pm

syncrodoka wrote: Solar parking structures are common in silicon valley. Cars are cooler and "free" electricity.

not exactly free. In fact it can be very expensive.

Thu Sep 08, 2016 2:41 pm

You didn't see the quotes around free???

Thu Sep 08, 2016 3:27 pm

Reflective mylar isn't much of an insulator when sandwiched as a layer within opaque materials. It would work great, however, as the top layer exposed to the sun. Reflective surfaces cause a large amount of the radiative heat from hot objects to 'bounce off' and a smaller amount to be absorbed. Painting a surface flat black has the opposite effect.

Peel and stick sound deadening material isn't a great thermal insulator. The Lizard Skin spray on thermal coating however contains a high volume of ceramic spheres within a binder, so it builds up a thin ceramic shell which retards heat transfer.

When I pulled the headliner over the cab of my Westy, I found a batt of fiberglass insulation. I replaced it with sound deadening material (for sound deadening) and a batt of 3M Thinsulate (TM) SM400L Acoustical Thermal Automotive Insulation which I found on ebay. The heat load through a westy roof isn't that bad since there is the fiberglass luggage carrier over the steel roof.

Thu Sep 08, 2016 3:35 pm

I don't think ill go with the thermal insulation or sprays. The white rooftop paint really appeals to me. I had a 2015 rubicon unlimited that was white with black hardtop. You could not even touch the hardtop, but the white surface was perfectly fine.

My trip to UAE I would have to say 3 out of 5 cars are all white.

I just don't want the white portion to be that visible. It looks like how dobryan painted it, you wouldn't be able to see the white when you are standing next to it.

Thu Sep 08, 2016 5:23 pm

Heat load was the primary reason I painted our yellow van's roof white. Its also a tough concrete floor product for durability as we use the roof a lot for loads, rooftop tent, etc.

When we have the roof top tent on the van for trips, there is a 4 X 8 sheet of plywood clamped to the roof racks up there for a nice platform the tent sits on. This "shaded roof" further cools the van when parked in full sun. So it can be a pleasant place to hang out with just a fan and the windows open.

We further foil the sun with silver reflective window panels in all windows, which does a surprising job keeping it cool. We have even left the panels in the rear windows (hatch, side glass to driver's B pillar) while driving as an experiment and found it to be of further benefit. Though you lose the cool view..

Thu Sep 08, 2016 7:02 pm

Steve M. wrote: tjet wrote: It looks like canvas pulled tightly over some type of rack - I like it.

It's aluminum like the rest of the Landrover.
There are also 4 vents that you can open on the roof underneath it on some models. You can see the two bulges in the safari roof where the air vents are at the front. The accessory list is somewhere near 4000 items so some Rovers have them and some don't. The original seats were just a piece of plywood and foam covered with vinyl.

Looks like this Rover had one. Interesting story too. Sorry to hijack

http://www.bbc.com/news/uk-england-bristol-33634960

Thu Sep 08, 2016 7:17 pm

tjet wrote:

Looks like this Rover had one. Interesting story too. Sorry to hijack

http://www.bbc.com/news/uk-england-bristol-33634960

Wow, great story in Rover tradition! yep it had one!
I'm trying to picture a rover style safari roof on a Vanagon. I'm thinking of replacing the plywood I have up there with a sheet of aluminum, mainly because the hot sun beats it down and it needed replacing last year after only a year. This time I tried a different sealer on it so will see how it goes.
The problem with the aluminum is I need to stand on it so it can't bend because I'm thinking about sliding the solar panels under it when not using them to give me more room on the topside. Flexible panels might be the trick, but they haven't reached the efficiency of the solid panels yet that I am aware.

Thu Sep 08, 2016 8:13 pm

Terry Kay wrote: Got a sheet of reflectix cut to the pop top size. It's held down with small tabs of velcro. When I'm done with it, it rolls up into a cloth bag tube. Works very well.

Get 3 'survival blankets'- thin foil with chrome-reflector finish. Tape them together. Use velcro to attach it covering the pop-top, and some light cord and several Neodymium magnets to pitch the forward end of it downward from the top of the poptop, so the front screened opening isn't blocked but the sun is kept off the front- even all the way to cover the windshield if you use 4. Another one, cut lengthwise in half and taped end-to end can be attached w/magnets to the side of the van facing toward the afternoon sun. Stuff your large cover or fold in half and roll it to store- those blankets almost disappear when collapsed.
Cheap, too.

Thu Sep 08, 2016 8:49 pm

RainierSyncro wrote: I have the headliner out of the Syncro

..
Is there a consensus of one product over another?
…
I don't plan to do anything with the outside... just inside.
…
some of the thermal blanket stuff… after applying something directly to the roof.

I wonder if layers of Reflectix applied directly to the roof might do both sound and heat insulation in one swell phoop? And whether the closed cell Prodex has better sound deadening properties than Reflectix which I think is just air bubbles?

Prodex pic

J Charlton wrote: Prodex http://www.insulation4less.com/Insulation4lessProduct-20-Prodex-Total-4-ft-x-50-ft.aspx
…
does a great job of keeping the interior warm in winter and cool in summer.

does it also deaden sound?
Would you recommend adhering to the ceiling?
Without a sound mat?

from http://www.insulation4less.com/default.aspx
What Makes Prodex Total Insulation Superior?
R-value 16 unaffected by humidity
Prevents 97% of radiant heat transfer
Vapor barrier
Prevents condensation
19dba contact noise reduction
90 degree Celsius (194 Fahrenheit) contact temperature rating
UV resistance
Does not promote mold or mildew
Does not provide for nesting of rodents, bugs or birds
Seals around nails (no leak)
Made with 100% recyclable virgin raw materials.

Fri Sep 09, 2016 7:56 am

After a really hot trip to Idaho one July, I painted the roof of my grey tin-top white and it made a huge difference to the interior temps.

Highly recommended.

Fri Sep 09, 2016 8:22 am

Jon_slider wrote: RainierSyncro wrote: I have the headliner out of the Syncro

..
Is there a consensus of one product over another?
…
I don't plan to do anything with the outside... just inside.
…
some of the thermal blanket stuff… after applying something directly to the roof.

I wonder if layers of Reflectix applied directly to the roof might do both sound and heat insulation in one swell phoop? And whether the closed cell Prodex has better sound deadening properties than Reflectix which I think is just air bubbles?

Prodex pic

J Charlton wrote: Prodex http://www.insulation4less.com/Insulation4lessProduct-20-Prodex-Total-4-ft-x-50-ft.aspx
…
does a great job of keeping the interior warm in winter and cool in summer.

does it also deaden sound?
Would you recommend adhering to the ceiling?
Without a sound mat?

from http://www.insulation4less.com/default.aspx
What Makes Prodex Total Insulation Superior?
R-value 16 unaffected by humidity
Prevents 97% of radiant heat transfer
Vapor barrier
Prevents condensation
19dba contact noise reduction
90 degree Celsius (194 Fahrenheit) contact temperature rating
UV resistance
Does not promote mold or mildew
Does not provide for nesting of rodents, bugs or birds
Seals around nails (no leak)
Made with 100% recyclable virgin raw materials.

a problem is this stuff cant breath, it could trap moisture between it and the roof, rust may result. use great care when putting non permiable materials inside the van against the walls or ceiling. condensation will find a way to get in between thru the smallest of holes, gaps, and once in, it is near impossible for that moisture to get out.

by putting a top over the roof (rover sun shade style) or painting the top white, you will be doing very good at cooling, with no risk of condensation build up.

Fri Sep 09, 2016 8:30 am

on the same topic... I wonder if there is any kind of peel and stick insulation for outside?

anyone knows?
thanks

Fri Sep 09, 2016 3:29 pm

Also being in the Pacific Northwest with that fine mixture of some warm days and a lot of drizzly days, I was careful not to create any pockets where interior (often moist) air will trap and condense out on the inside of my van. Ask anybody who's stuffed their walls with fiberglass what happens later.

FWIW, I used FatMat, carefully applied with no open seams, then Reflectix glued to that with contact cement. I figured I had a better shot at "airtight seal" with the back of the FatMat stuck to the body panel, plus the mass reduces sound transfer through the body panels. I stopped 1/8" or so shy of any seams so there wouldn't be any pockets to trap moisture.
Reflectix isn't the end-all of insulation but it does substantially reduce radiant heat gain (your roof absorbs heat energy from the sun and re-radiates it downward into your Van, the small air gap inside the Reflectix and the foil face tend to reflect that energy back upwards. Not perfect, a larger air gap would make it better but then it would be too thick perhaps). Since the Reflectix is sealed there won't be condensation inside of it. I also painted my pop-top and luggage rack glossy white.
Inside the pop-top I only used Reflectix as I didn't want the extra weight of FatMat up there. But rusting isn't a problem with a fiberglass top either.

Fri Sep 09, 2016 5:36 pm

bluebus86 wrote: Jon_slider wrote: RainierSyncro wrote: I have the headliner out of the Syncro

..
Is there a consensus of one product over another?
…
I don't plan to do anything with the outside... just inside.
…
some of the thermal blanket stuff… after applying something directly to the roof.

I wonder if layers of Reflectix applied directly to the roof might do both sound and heat insulation in one swell phoop? And whether the closed cell Prodex has better sound deadening properties than Reflectix which I think is just air bubbles?

Prodex pic

J Charlton wrote: Prodex http://www.insulation4less.com/Insulation4lessProduct-20-Prodex-Total-4-ft-x-50-ft.aspx
…
does a great job of keeping the interior warm in winter and cool in summer.

does it also deaden sound?
Would you recommend adhering to the ceiling?
Without a sound mat?

from http://www.insulation4less.com/default.aspx
What Makes Prodex Total Insulation Superior?
R-value 16 unaffected by humidity
Prevents 97% of radiant heat transfer
Vapor barrier
Prevents condensation
19dba contact noise reduction
90 degree Celsius (194 Fahrenheit) contact temperature rating
UV resistance
Does not promote mold or mildew
Does not provide for nesting of rodents, bugs or birds
Seals around nails (no leak)
Made with 100% recyclable virgin raw materials.

a problem is this stuff cant breath, it could trap moisture between it and the roof, rust may result. use great care when putting non permiable materials inside the van against the walls or ceiling. condensation will find a way to get in between thru the smallest of holes, gaps, and once in, it is near impossible for that moisture to get out.

by putting a top over the roof (rover sun shade style) or painting the top white, you will be doing very good at cooling, with no risk of condensation build up.

WRT comparing Reflectix and Prodex. Reflectix is significantly cheaper and while it is a good insulator it has real shortcomings relative to Prodex
1. the insulating material (Reflectix) is the air trapped in bubbles between the reflective sheets - air bubbles expand and contract with heat and cooling and break if contacted hard enough, leaving voids with no insulative value. These voids, if the contact was hard enough to penetrate the reflective layer will let potentially moist air in and allow it to contact the other reflective layer that is applied directly to the van roof. Because the Prodex has a closed cell foam inner layer it is a far better, more durable insulative layer - even if the inner reflective "skin' is breached, the closed cell foam prevents energy conduction and moist air migrating to the van metal roof
2. The prodex really flexes and forms nicely to the various shapes and contours that it is applied to. When applied with contact cement one can literally mold it into place. With either Reflectix or Prodex all edges, seams and joins should be carefully covered with reflective tape - both are effective vapour barriers but the Prodex is less prone to failure due to contact. (see above)
I suggest reading / rereading the article re insulation and condensation on
http://canadianhightops.ca/condensationandinsulation.html
might yield some insights into the role insulation plays
WRT acoustic insulation - I do not have any quantifiable data to make any definitive statement about it. However, anecdotaly, I have driven a van with an uninsulated hightop on it and the same van after the top was insulated - sure seemed a lot quieter insulated. However, having said that, the van was quieter with either the insulated or non-insulated hightop on it than it was with the westy poptop.
One other note about Prodex - it is such nice, effective "stuff" to work with that you're going to find about a thousand other uses for it if you have any extra - I've even used it as an ground pad under my sleeping bag when camping in a tent - I find that the the insulating material of my sleeping bag (Holofil) gets compressed by my weight and becomes less effective under me than it is on top - result - I feel the "cold" emenating from the ground. A single layer of Prodex reflects the IR of body heat back up and I do not feel the cold at all.