Roof Deck Cooling Effects

[Kenny]

I know there are few that have recently installed decks on their roofs. Have you noticed a change in your air conditioning loading? Seems it would lessen the load because the bus roof is now shaded.

[Joe Camper]

We have a roof deck and it's on a black bus.

I can not tell you if it was any different from without, we bought the bus and it was converted from new with it.

I am pretty confident it goes a long long way to aiding in the comfort level in the bus in hot weather.

How could it not? I have been meaning to put louvered vents into the side skirts of the deck that hide all the hardware to add additional airflow.

Our deck is 8 by 21ft. Next Jan we are going to the Keys with our son and daughter-in-law and they will sleep in an 8 by 12 tent pitched on...........you guessed it, THE ROOF.

Yes, we are not your normal or average Prevo owners. I need to learn how to put up photos here LOL

[junkman42]

Many years ago I had a land rover 88 with what was called a tropical roof.  It had a over roof that stood about 2 inches off the normal roof on insulators and it definitely kept the interior at a much lower temperature!  Funny that with the new modern style the only option is air conditioning,  john l

[Jerry W Campbell]

I don't have a deck but my roof is almost completely covered with solar panels. I am sure it helps a lot. More shade.
Jerry  

[Len Silva]

I can't help you directly except to say that I had an outbuilding in Florida with a leaky shingle roof.  I put furring strips and a metal roof over it and it made a DRAMATIC difference in the inside temperature.

[Charles in SC]

There were some busses built for use in Saudi (I think) that had a double roof for just that reason. I saw a picture of one once. I think it was a Eagle.

[Van]

Heres a couple of the Eagles that went over there, courtesy of smoothjazz, thanks Dan.




     Van

[eddiepotts]

Joe I want to see them. I use photobucket to post pick. After I upload my photo to it I just copy the image code and paste it in.

[BG6]

You need two things for this to work:

First, you need to shade the roof, without simply transmitting the heat into the coach through your support structure.  Wood is a poor conductor of heat, so if you have wood decking, you're good here.  If using a metal structure, you can design it to be a heat sink between the deck and the coach.

Second, you need airflow between the roof and whatever is shading it.  This removes whatever heat is radiated through the shade.  If you are supporting the deck by placing it directly on the roof. drill a few small holes to let hot air escape.  Don't forget the paint or varnish in the holes to prevent rot.

The optimum design is one which is raised an inch or two above the roof, supported only at the roof supports (pillars between windows) and by posts extending to the roof without blocking airflow.

The more shade on the roof, the better.  Solar panels are great, but don't forget the shade given my aircon units, satellite dishes, flags, etc. -- and don't forget the sides, when you are parked.  Awnings give you a LOT of cooling, by shading the sides and keeping the sun from coming through the windows and heating the interior.

Your coach color makes a difference.  Lighter paint schemes reflect heat better, and every photon that bounces off is one less photon that your aircons will have to struggle against.

There is also reason to believe that vortex generators improve cooling, when you are going down the road.  By breaking up the vacuum behind your coach, laminar airflow along the sides is improved, pulling away just a little more of that heat on the sunlit side.

[Barn Owl]

There were some busses built for use in Saudi (I think) that had a double roof for just that reason.

"A total of 380 MC-5C were built, many as special orders rather than in regular production. Greyhound bought 198 for a contract in Saudi Arabia, 49 of which had a unique central exit door. After the end of the contract they were sold in the US, where they can easily be recognized by their double roof. Some of the buses had their second door removed, but others continued in service with this unusual layout."

Linky: MCI Buses and Coaches

Photo: Saudi Bus with double roof

[bevans6]

Thanks for the picture of the Saudi MC-5C.  I love the roof - I can see one like that finding it's way on top of my MC-5C at some point, wouldn't be all that hard to do!

Brian

[Joe Camper]

Eddie I will be doing a mock up with the tent at home real soon to figure out how we will secure it to the diamond plate floor up there, and while Deb is away too.

This is one I will be apoligizing for afterwards not asking permission in advance.

Too many great ideas have been cut down with that mistake.

[NewbeeMC9]

Caribiners through matching holes in the plate.    Cheap and easy