Lighter version of Bob's plywood roof cover for CT?

[Seldom]

Can I do this:

On this:


I have a 7x12 CT that I am converting into a tiny home/camper. I would like to build an awning similar to the one that Bob has built and is in the 'Warm in Winter/Cool in Summer' article, but I think that the weight in wood needed to cover the roof of a 7x12 would make it top heavy. Maybe I am overly concerned? It would be at least 200 pounds I would guess with plywood and necessary 2x4 cross supports going lengthwise along ladder racks, those are kinda heavy steel and add a lot of weight as well. Then there's the panels which will go up there. None for now, but up to 400-600Watts planned for the future. Plus if I put an awing to go over street side, more weight. My weight budget is getting pretty tight up there. My overall weight budget is only around 2100lbs. Would rather spend that weight on supplies and not build weight. 

So I wonder if I can lighten it up somehow? Thinner plywood with more 2x4s? Maybe a fabric (shade or UV reflecting greenhouse material?) that can stretch over ladder racks when in use and rolled away when trailer is moving? Problem with this is I cannot easily reach roof and set something up because of spine issues, so it would have to be mechanized somehow, seems difficult... I cringe when I think of having to unfold the roof top tent that once was on top of my SUV, that was painful.

I thought it would be cool to do an insulated awning made of polyiso sandwiched between 1/4 plywood and attach panels directly through to ladder racks, but I have no way to determine what is safe to drive around with considering air drag and the risk of something falling apart on the road, plus I am very limited in cash and physical strength so I don't want to try and reinvent the wheel at this point.

Thanks for any ideas, links, advice, etc!

 

[tx2sturgis]

Park under a tree maybe?

Or maybe stretch a big roll of reflectix over the trailer?

I coated the top of my roof with white roof sealer and it helped a lot.

 

[kaBLOOnie Boonster]

Is this a "I need something to do" project? If so, there is nothing wrong with that. Have fun with it.

But it doesn't seem desirable to put fabric outside, especially in the high desert wind. Awnings have been against my religion for years. Anything that goes up and down seems undesirable, too.

What problem is all this trying to solve in the first place? I don't feel heat coming through the roof.

 

[highdesertranger]

if you are putting panels up there, why do you need plywood? I wouldn't even use wood. bolt the panels to the rack. if you need more support use aluminum. highdesertranger

 

[John61CT]

Yes, form follows function, specify what exactly you're trying to accomplish. I see no use case for wood up there at all, other than low cost.

To the extent you're disabled you will need to spend more money, both in less DIY and in ease of use.

Shade requires no rigidity or load bearing strength, side-mounted awnings are bog standard available off the shelf, hand-cranked or electrically deployed.

Semi-flex solar panels are light weight and can be well mounted on a grid of lightweight aluminum sheet and tube profiles.

Rigid framed panels much cheaper and last longer, but heavy.

Big question is what else needs to be up on the roof?

 

[Seldom]

tx2sturgis: I have a spot available to park for free, but there is no shade. Sun travels directly over valley and shade is cast everywhere but the valley where I can park. Valley walls are steep canyon covered in chaparral and poison oak, at least the bunnies get shade. Roof sealer is a great idea, still haven't got around to that but I will bump up on priority list!

kaBlOOnie: This is more of a "I need to not live inside a solar oven" type project haha! Even with insulated roof its getting pretty hot. Any light coming into the trailer during day feels like a laser beam. High UV index, even when its 70 the sun is stingy. It doesn't get crazy windy in the valley I am parked, but agreed, high desert wind and awnings are a bad combo! This winter I parked outside of Palm Springs and the Santa Anna winds completely destroyed my neighbor's fancy and very durable looking slide out awning on his 5th wheel.

highdesertranger: I have pretty low power requirements, wont need that many panels. Main job is to act as a sun shield, takes the heat so the roof doesn't have to.

john61CT: The primary function I want from the roof awning is to be a sun shield, a structure that covers the roof so that the heat is reflected before it has an opportunity to absorb into trailer roof. I don't want to be dependent on finding shade, that is what I like about bob's roof awning, its always casting shade directly over trailer. The 2 roof vents on either side of my trailer would be shaded and could be left open, the breeze would pass between and push away any heat radiating from roof awning before it could be absorbed into trailer roof.

As far as what I would put up there...not much. I want to keep weight as low and balanced as possible for towing safety. The roof awning and the panels would be it. For side of trailer protection I would use shade cloth with grommets around edge secured with bungees, very easy to put up, and if the wind picks up it's easy to take down and wouldn't be needed anymore anyways. Can't afford the weight or cost of a fancy automatic side awning, and even an ARB touring awning is more trouble than its worth in my experience. I park across from door and make a "courtyard" as seen in some of bob's YT videos. I would mount some solar panels to the awning as I get them, I plan on picking them up as I go. I can charge from neighbors home and have some small Li-Ion battery packs that I live on for now. I am at a pretty basic level of build at this point as my injury happened at the beginning of the build, so I have insulated walls and new wood panels for walls, but everything else is temporary.

Summary: Since bob's awning was built on a 6x10 CT it uses less weight than it would if built on my 7x12 V nose CT, is there a way to lighten up bob's design? Seems like aluminum is a good material to replace 2x4s, but what about plywood? How do you build with aluminum, just drill and fasten with nuts and bolts?

Thanks for all responses, much appreciated!

 

[highdesertranger]

yes with aluminum you would use nuts and bolts. IMO aluminum is a much better choice. highdesertranger

 

[John61CT]

Make sure if you go with semi-flex panels, that they are mounted so they stay rigid, no movement of the cells, especially while driving.

 

[Seldom]

Thanks, I will use aluminum for sure. Its a bit intimidating due to unfamiliarity with working with but I like that it can be bolted together, that makes it fairly simple. I was thinking I would go with good ole renogy panels because I could tilt them and they are cheaper and more durable, but am interested in semi-flex for the weight difference...any suggestions for best brand?

 

[DannyB1954]

I covered my van roof with 960 Watts of solar panels. No plywood. This does add weight though. Have you seen those wavy fiberglass panels that are used for patio roofs? Green is the most common, but they do come in other colors.

 

[Seldom]

DannyB1954: NICE! That is some serious power! Well if you think about it all that weight in solar panels is still lighter than plywood and definitely more multipurpose. I have considered that material, but am afraid it might tear apart while driving at freeway speed, but who knows? I am getting more tempted by the prospect of semi-rigid panels. 5.6 pounds for 160 watts is pretty awesome, but then it needs some kind of frame or support, which adds weight, and can't be tilted. If it covered entire roof, wouldn't need to tilt. Still considering a mix of suitcase and roof also, so I can park in partial shade or full shade and still charge up, albeit not as quickly.

 

[DannyB1954]

Still considering a mix of suitcase and roof also, so I can park in partial shade or full shade and still charge up, albeit not as quicklyhttps://vanlivingforum.com/member.php?action=profile&uid=10092

If your roof is covered in panels, it s in the shade. You can see my panels here