Rooftop insulation?

[jronwood]

I am pondering an idea to insulate my fiberglass hightop not only from the INSIDE (closed cell spray/rock wool) but also whether i should bridge the 3/4" on the topside between the ribs and skin it with diamond plate aluminum. I plan on spending many nights up there. I could leave the 3/4" gap as "open air" and let heat ventilate (like the nylon camper sun shields you see used out west for intense radiant heat on large RVs and 5th wheels. Those nylon ones are 12" or more off the roof .. mine would be 3/4" BUT it would allow air movement. Any thoughts or experiences?

 

[Bikersmurf]

3/4” doesn’t seem like enough clearance with aluminum.

We rented a 5’ x 12’ trailer from UHaul. Its aluminum roof got hot enough in the sun on cooler day to give me a first degree burn on my arm, when I brushed my arm against it. It was still very hot if you were an inch away. I’d be concerned that the aluminum would absorb the heat from the sun and then transfer it to your roof.

The one difference being that there wasn’t as much circulation, but I don’t think 3/4 of an inch would be enough.

 

[jronwood]

3/4” doesn’t seem like enough clearance with aluminum.

We rented a 5’ x 12’ trailer from UHaul. Its aluminum roof got hot enough in the sun on cooler day to give me a first degree burn on my arm, when I brushed my arm against it. It was still very hot if you were an inch away. I’d be concerned that the aluminum would absorb the heat from the sun and then transfer it to your roof.

The one difference being that there wasn’t as much circulation, but I don’t think 3/4 of an inch would be enough.

Thanks for that input. I would love to find some of the old Marsden Mats that were aluminum. I have a TON (literally 2 ton to be exact) of steel ones , just too heavy to cover an entire roof with them AND then there is the rust bleeding issue even IF you powder coat them

 

[rruff]

We rented a 5’ x 12’ trailer from UHaul. Its aluminum roof got hot enough in the sun on cooler day to give me a first degree burn on my arm, when I brushed my arm against it.

What color was it? There is a reason why airplanes where originally bare aluminum, and now they are painted white (mostly).

Aluminum is a great heat conductor which is why if it's hot, it will burn. An insulative material would be much less obvious at the same temperature.

I am pondering an idea to insulate my fiberglass hightop not only from the INSIDE (closed cell spray/rock wool) but also whether i should bridge the 3/4" on the topside between the ribs and skin it with diamond plate aluminum. I plan on spending many nights up there.

It's white, a good color for keeping the temp reasonable in the sun. Just sleep on that. No reason to put another layer on for sleeping at night... or any other reason I can think of.

Directing your wheeled vehicle to the mountains in summer solves a lot of potential issues as well...

 

[FAW3]

Our Bluebird Wanderlodge had the entire roof covered with aluminum step plate. It was mounted with rubber strips about 1/2 inch above the roof screwed down to the ribs. No leaks. Could sit up there in chairs. Insulation value minimal …usefulness maximum. We sold it after 17 years…but now at 40, the new owners still run her.

 

[Peter_n_Margaret]

A sheet of fibreglass/PUR/fibreglass sandwich panel.
No support required except around the edge. Chuck out all that other stuff inside.

This pop-top roof panel is just 20mm thick. 50mm would provide better insulation.

Cheers,
Peter
OKA196 motorhome

 

[Bikersmurf]

What color was it? There is a reason why airplanes where originally bare aluminum, and now they are painted white (mostly).

Aluminum is a great heat conductor which is why if it's hot, it will burn. An insulative material would be much less obvious at the same temperature.


It's white, a good color for keeping the temp reasonable in the sun. Just sleep on that. No reason to put another layer on for sleeping at night... or any other reason I can think of.

Directing your wheeled vehicle to the mountains in summer solves a lot of potential issues as well...

Oxidized Aluminum. Super hot in the sun.