Reply
 
Thread Tools Display Modes
 
Old 02-20-2017, 09:41 PM   #1
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 207
Solar heat gain reduction for roof using a cover deck?

I am curious about those who may have a deck installed over their bus or know of those who do have one. How much does having a deck provide solar gain reduction on the roof of the bus?

I would like to make our bus as efficient as possible and it seems that most of the comments I see about skoolies being hot, revolves around the bus not being parked in the shade.

It makes sense to me that a deck over the entire top of the roof would provide a huge thermal break from direct sun. Additionally, it would provide the ability to mount various items like solar panels or a condenser unit from a split system, without having to make any holes in the roof.

I would be interested in thoughts about this. Are there any downsides to adding a roof deck to a bus?
__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-21-2017, 07:17 AM   #2
Bus Nut
 
superdave's Avatar
 
Join Date: Mar 2015
Location: hills of sw virginia
Posts: 758
Year: 1996
Chassis: thomas
Engine: 8.3 cummins
Rated Cap: 11 window
it would probably affect the mpg a little. it would help some being shaded but you would have to shade the whole bus. light hitting the sides/windows is also just as bad. I'm in fl in direct sun now just testing my foam job. I'm very happy with my bus, in hot and cold weather. the side the sun hits is hot, I'm going to have another set of shades made. trying to figure out a little outside canopy I can clip on to shade the windows.
__________________
living in a bus down by the river.
my build pics
https://www.skoolie.net/forums/membe...albums942.html
superdave is offline   Reply With Quote
Old 02-21-2017, 08:30 AM   #3
Bus Geek
 
Tango's Avatar
 
Join Date: Mar 2011
Location: Houston, Texas
Posts: 5,077
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
The "second roof" idea works and can make quite a difference. All the old safari Land Rovers employed a standoff roof just above the factory one to allow air flow in between. Basically, you are carrying your own "shade" everywhere you go. And I have had a number of bus converter friends who have gone the roof deck path over the years and they all saw a big difference in what it took to cool their rigs. I am going that route myself.
Tango is offline   Reply With Quote
Old 02-21-2017, 12:53 PM   #4
Almost There
 
Join Date: Aug 2014
Location: Oklahoma
Posts: 82
Year: 1984
Coachwork: Ward/Amtram
Chassis: International 36ft
Engine: DT466 w/ Allison MT643
I'm seriously looking into building a shade of solar panels over my next bus's roof, with airgap, and extra solar panels that fold/slide out over the sides of the bus for both more power and more shade
dalez is offline   Reply With Quote
Old 02-21-2017, 01:35 PM   #5
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 207
Quote:
Originally Posted by Tango View Post
The "second roof" idea works and can make quite a difference. All the old safari Land Rovers employed a standoff roof just above the factory one to allow air flow in between. Basically, you are carrying your own "shade" everywhere you go. And I have had a number of bus converter friends who have gone the roof deck path over the years and they all saw a big difference in what it took to cool their rigs. I am going that route myself.
I did not know that about land rovers! That is very cool! Sounds like I am on the right track!!

This is the currently my favorite of the attachment methods. It is light, minimal wind resistance and the design would allow me to attach other things to the vertical supports, such as additional foldable pipe along the edges that we can install a full length window canopy.

I happened to have 40' x 4' of painters drop cloth (much heavier than we would use) and I rolled the full length of it up attached end to end and the roll was less than 12' in diameter. This is more than enough material to create a nice angled canopy down from the roof line, above the windows and it wont take up a ton of storage space. We will have a small porch coming off of the back door and I will create a small storage unit under that to house it.

Composite decking seems to be the most common thing that I see in roof racks and makes sense. I am just wondering about the difference in weight compared to regular wood. I did find some open cell decking (think corplast) that looked interesting, but it is going to be EXPENSIVE!

I will likely not use wood for the cross members, but instead, another piece of pipe and then use U-bolts to attach to the pipe.

Link to full conversion photo thread - April 2 - SeanF


Click for large view
- Uploaded with Skitch
__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-21-2017, 02:00 PM   #6
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 207
One thing that I think I will have to address though, with this design, is how to insert a thermal break between the mounting brackets and the bus. I think I can probably just sandwich some thick felt between the bracket and bus and this should provide some form of thermal break so that heat gain from the deck and the pipe is not transferred to the bus body. Granted, this solar gain would be minimal, but easy enough to try and avoid.
__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-21-2017, 02:23 PM   #7
Skoolie
 
Join Date: Jun 2016
Location: Orange County, CA
Posts: 163
Year: 1990
Coachwork: integral
Chassis: Crown Supercoach II
Engine: Detroit 6V92TAC, Jake brake, Allison HT740
Rated Cap: 37,400 lbs GVWR
I first repainted my entire roof down to the gutters with gloss white Rustoleum enamel with Thermacels insulation powder added - it made a slight difference to ceiling temperature. I then built a walkway between my two roof hatches to which are hinged the eight big grid-tie solar panels. When the panels are stowed down against the roof for travel there is still several inches of airgap under them, more than enough to allow air to circulate under them. This makes a noticeable difference to ceiling and interior temperatures, and will also help the panels from getting too hot. So far, so good.

In the 1970s (I think) MCI built some of their MC5 buses for Aramco in Saudi Arabia, and they have a double roof. It appears to be only an inch or two above the roof itself, but apparently it does help in hot weather. There is someone who advocates making double roofs over existing roofs of bus conversions - I forgot his name, but he has a webpage talking about it.

Didn't that old Series 1 Land Rover ("The Anti Christ") in The Gods Must Be Crazy have a tropical roof? It's been quite a while since I've seen that film, so who knows?

John
Iceni John is offline   Reply With Quote
Old 03-19-2017, 11:44 AM   #8
New Member
 
Join Date: Mar 2017
Location: Pasadena Tx
Posts: 3
A different approach on heat

Anyone ever look into self adhesive TPO vinyl roofing??? Wide enough to cover well over the edges, no seams, and in its regular application is energy star rated. In putting a deck on the roof, check out the Denali bus build on you tube, episode 7 I think. This is how I will be doing my deck. Reason being, no direct mounting to the roof itself and no potential for roof leaks. Also designing an arched solar panel canopy that goes up and down. Up for the shaded part of the deck and to get the solar panel heat build up as far away from the roof as possible, and down for travel.
jimburke77502 is offline   Reply With Quote
Old 03-19-2017, 01:25 PM   #9
Bus Crazy
 
Robin97396's Avatar
 
Join Date: Feb 2016
Location: Willamina, Oregon
Posts: 2,243
Year: 1997
Coachwork: Bluebird
Chassis: TC 1000
Engine: 5.9
Send a message via Yahoo to Robin97396
Quote:
Originally Posted by ourmefa View Post
I think I can probably just sandwich some thick felt between the bracket and bus and this should provide some form of thermal break so that heat gain from the deck and the pipe is not transferred to the bus body.
If you can get some scraps of an old rubber conveyor belt it would work well, but felt would be better than nothing.
Robin97396 is offline   Reply With Quote
Old 03-19-2017, 01:55 PM   #10
Bus Crazy
 
Robin97396's Avatar
 
Join Date: Feb 2016
Location: Willamina, Oregon
Posts: 2,243
Year: 1997
Coachwork: Bluebird
Chassis: TC 1000
Engine: 5.9
Send a message via Yahoo to Robin97396
Iceni John, thanks for the TPO info. That actually sounds like it has high potential.

Excerts taken from; https://www.roofingcalc.com/tpo-roofing-pros-and-cons/

Quote;
For most residential applications, TPO membranes come in two thicknesses options: 45 mils (.045″) or 60 mils (.060″). Commercial grade TPO membranes may have a thicknesses of up to 80 mils (.080″) and may come in up to 12 feet-wide rolls.
The width and length of the membrane can vary depending on the manufacturer, with a typical TPO membrane roll being 6 to 6.5 ft wide and 100 ft long. Other membrane thicknesses and widths are also available depending on the manufacturer, including a 3 feet-wide rolls for the edges of the roof. Commercial grade TPO membranes may have a thicknesses of up to 80 mils (.080″) and may come in up to 12 feet-wide rolls.
They are available in white, light gray, and black colors. White TPO roofs offer the best heat reflective properties are are consequently the most popular choice due to their energy-saving potential.
Hot-air welded seams are very strong, with seam strengths being as much as 3-4 times greater than EPDM adhesive and tape seams.
A TPO membrane is considered to be a cool roof and is Energy Star rated. Not all TPO membranes are created equal, and some perform a lot better than others.
Endquote;

This stuff sounds pretty good especially for a bus with challenged roof seams (a leaker). A walkway down the center line of the roof would probably be a good idea to avoid walking directly on the TPO. At the same time this material doesn't make much sense if someone has a deck. It was priced at $5 to $7 per square foot installed residentially, so the self installed price should be significantly lower.

Personally I'd rather have a deck over the roof if I were making a choice in this bus.
Robin97396 is offline   Reply With Quote
Reply

Tags
cool, deck, heat, roof, solar

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Virginia Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 11:45 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.