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FWC roof load problem

Granby roof storage rocket Box

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#21 Northbynortheast

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Posted 17 December 2018 - 04:16 PM

Sorry for your trouble,

You’ve found what I consider to be the Achilles heel of this camper. The design of the roof it seems, cannot deal with much point loading. Unfortunately you don’t have to do much Googling to find others that have damaged their roofs. With what you are trying to carry you are well overloaded and that the roof is sagging indicates that it has been fatigued. A new/healthy fwc roof should have a slight upward bow to it. I engaged fwc in a discussion about this issue recently and suggested to them that a solution to this problem would be to mount the Yakima track on outboard most roof beams where any weight on the racks would then have the full support of the outer walls. The company/engineers argued an indefensible position that what they are doing now is as strong. It seems too that it would not take that much additional weight or height to bolster the design for a stronger roof. For now, I’d recommend moving the cross bars as far from the center of the camper as possible and get the load on the roof certainly under 100 lbs.

Good luck

Edited by Northbynortheast, 17 December 2018 - 04:18 PM.

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#22 Wallowa

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Posted 18 December 2018 - 01:07 AM

Hmmm..like so many "issues" discussed on forums the true extent of any problems is never know...only guessed at, and in my experience, most often overblown...

 

FWC has been building campers for how long?  And how many tops/roof panels have been damaged due to overloading is for the devine to know and not mere mortals..certainly to someone with a damaged roof it is significant..

 

Sure you can overload the top and damage it....but in my mind that is "operator error"....I feel that FWC does not have a poorly designed roof structure but rather many of us try to take that design beyond it's intended use.

 

I think the roof of a FWC is not intended or suitable as a cargo platform for heavy or bulky items; for a plethora of reasons already mention in this thread...but that is just me and we each do what floats our boat... :D


Edited by Wallowa, 18 December 2018 - 01:09 AM.

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#23 Northbynortheast

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Posted 18 December 2018 - 02:59 PM

Wallowa,

I basically agree. I’m not unhappy with our fwc. There are just things that can clearly be done better, fwc constantly improves things over time. It would cost nothing to move the Yakima tracks outboard, above the wall for a huge gain in load support. Can anyone chime in with a plausible reason why they don’t this? I can see no construction constraints. The only reason I’ve come up with that makes any sense is that the length of load bars needed to accommodate this change are about double the cost of the ones used. Simply brushing numerous roof problems off as operator error, hmm. I think lots of folks would expect that a camper that is supplied with Yakima tracks/ bars should be able to handle 100-150lbs. I just re-skimmed the 2017 owners manual, the “load limit” for both the fixed aluminum rack and Yakima tracks is “small lightweight items”. FWC should be a fair bit more clear with weight restrictions. I wouldn’t even dare to put an average 85lb canoe on the roof and venture down a rough road. Yes there are lots of fwc users out there with roofs that are fine, lots of folks don’t carry stuff at all, there are way too many examples of bent roofs from “overloading”, easily found on the web. Also once you are aware of this, and look for it, there are lots of roofs out there with reverse bowing, many owners seem unaware that it has been fatigued. Then there’s the issue that also pops up frequently of owners who forget to undo the “midpoint” latches or the clip doesn’t flip and they kink or bend their roof. This is clearly operator error. Could it be avoided/improved? Are the midpoint latches necessary? Should a person of average strength be able to destroy a $5000 roof so easily. Why not go to a rectangular section aluminum for the roof frame, rather than square tubing? A small height/weight penalty for a substantial gain in strength.
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#24 Wallowa

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Posted 18 December 2018 - 05:29 PM

Good discussion...multi points and ideas laid out...as always we need to open up and identify the problem, the extent of the problem, the cause of the problem and of course any corrective or preventative measures we can take.  Of course everyone has a different perspective on these points.

 

Agreed that 100-150 lbs should not damage the roof if correctly loaded...I doubt if it does. But why add that stress? 

 

Lots of factors here...how tightly the load is secured [does it flex or bounce?], where it is loaded on roof, how it is loaded up and off of the roof, type of road driven with load on roof [washboard, rocky uneven tracks?], speed driven and of course how many pounds.

 

Regardless of the additional load on the roof, every time the top is raised the roof is raised at an angle [back first, then front] which torques the roof structure, big lever arm...mid-point latches not withstanding, the latches most often forgotten that cause damage are the front latches that if not undone will greatly magnify the stress to the roof when an attempt to raise the rear of the top is made..add a mechanical lifting device inside the camper and you lose feed back that something is wrong which you would get if you had been lifting by hand.

 

Look in my view, and I could be wrong, the roof of pop-up camper such as our FWC units is not the location to add weight or height..

 

Why?  Our campers are by design lightweight and purpose built to withstand the side to side and end to end twisting when driven off road and with the top latched down....two slender supports at extreme ends of the top when it is up can not hope to support 100++ or more lbs, especially in high winds which moves the entire structure or when a snow load is added...and as mentioned during raising or lowering when torque is applied to the top with extra weight can cause damage.

 

It is not the strength of the owner that can damage the top; it is the owner's poor judgement or inattention that damages the roof structure [me included]...raising and lowering an unloaded FWC roof is a grunt at best but doing so will not damage the integrity of the top...adding weight and forgetting to unlatch damages the top structure.

 

Last comments and then I promise to shut up....putting more weight on a lightweight camper is counter productive; add more weight higher on the camper diminishes the stability and can stress the entire unit structure...most of us, again me included, tend to load up a bunch of "nice to have" but don't really need items...we go down the rabbit hole of thinking our FWC is the Swiss knife of campers, it is not.  My '16 Hawk is in my opinion a well constructed, well designed, lightweight camper that allows me to prowl off road in comfort; but it is not a platform for an endless array of toys or gadgets...my experience in long distance solo sea kayaking, backpacking and back country skiing has me in good stead when loading out my Tundra and Hawk; I try to have restraint when figuring my load-out...sure I play "what if" but you can't have it all; take what you need leave what you don't...sometimes in my opinion regardless of the pursuit you need to say 'enough is enough' and re-focus on going with the KISS edict...less is often more.  Even the best system can be defeat with abuse.

 

Out Here...Phil 


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#25 PokyBro

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Posted 18 December 2018 - 07:53 PM

Thought I'd weigh in with a few photos and comments as well on this topic. My build was a 1981 Grandby, shortened to fit a short bed pickup. When I came to renovating the roof portion, there were a number of things that concerned me. At that time (1981) FWC used 1x1 inch tubes for the center five struts going lengthwise across the roof. The camper had experienced a snow load or two over the years that had caused the roof  to become somewhat concave. My solution was to turn the roof upside down on the driveway, place a 2x4 on the front and back lip and carefully walk out a convex shape back into the roof. However when I placed the roof back on the camper body, I noticed there was still a fair amount of flex and bounce that I was not comfortable with. My solution for my rig was to add 5 additional 1x1 inch tube struts side by side to the existing ones and screwed together along the length and connecting at each end with L brackets. To me this doubled the strength of the roof for loading, and I have a lot more confidence it will hold up to snow loading now with the reinforcement.

 

Moving forward to current material FWC uses for the roof. The five center struts are 1 1/2 or 1 3/4 inch by 1 inch rectangular tubes with a convex curve added. The periphery tubes around the side edges are still 1x1 inch tubes. This allows for a bow to be in the center portion of the roof, with a downward slope to the outside edges, giving good water drainage properties. 

 

As has been stated above, this system has been used for decades and has functioned very well for intended purposes. I have noticed slight dipping on my camper on the outside edge where the sideliner attaches and hangs down as it is, since there is some weight to the fabric itself front to back on each side, and it was stretched and tightened to prevent bagging.

 

My concerns with carrying loads on to top are as follows. The Yakima tracks are held down with with #8 screws about every 6 inches or so, into thin walled aluminum tubing. The track likely doesn't add a significant amount of rigidity to to the roof struts. So while downward pressure of a reasonable load works, I also wonder how much upward strength the attachment screws can bare, in the case of carrying canoes, for example, where wind lift is possible. From my point of view putting the tracks on the outside tubes along the side edges, while being stable buoyed up by the outside wall they rest on with the roof in the down position, would add further weight while the roof is in the up position. I'm sure some would leave a load on the racks while in this up position adding to the stress on the 1x1 inch outside tubes. Could FWC change these outside tubes to the same inside rectangular tubes described earlier? Yes perhaps, but that would require additional changes as well, including for example, the trim ring covering the sideliner. There would still be limitations on the amount of weight they would carry. I'm in the same dilemma of wanting to add some racks to haul a canoe, but I'm not confident in adding towers to my Yakima tracks will be strong enough. I'm trying to come up with a solid mount, that will work without issue.

 

I don't know if my thoughts make that much sense, but I wanted to also add some photos per David Graves request for reference.

 

 Poky 

 

Roof Frame
Roof Frame
Roof frame on side
Reinforced roof frame
Reinforced roof frame
Roof installed
Roof installed

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#26 klahanie

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Posted 19 December 2018 - 12:55 AM

Now that the OP has been answered, a few thoughts ...

 

Northbynortheast, I'm no expert, self anointed or otherwise, and can't speak for the mfr but I think the manual lift part of the roof would be a reason for not redesigning the rack to allow the carrying of much more weight. How the OP could lift 250lbs, I can't imagine.

 

A few years back FWC added struts as standard equip to aid in lifting - an acknowledgement I'd say, that even a fairly light load, like solar panels, could tax the user. Now that, thanks to the popularity of compressor fridges, solar is common on newer campers, I'm thinking fewer owners will have room up top for cargo and therefore the desire for increased load capacity.

 

I don't like the idea of a hundreds of pounds of weight up top because the roof is clamped to the side walls. The ability to give a little between the roof and walls probably helps the whole camper accommodate flex without cracking. If so, lighter is better than heavier.

 

I used to carry a spare tire on the roof, at the rear. I blame that weight for small holes forming in the vinyl, top of each rear corner. The vinyl of course is trapped under the roof weight, again a lighter, floating roof is better here.

 

I have though carried a 70-80lb canoe, supported by the front and rear cross bar, may times on rough roads without incident. I wouldn't hesitate to do the same on a newer model. Ours is a '97, still with a nice rising bow in the middle. I've read on these pages that the AL tube wall thickness has increased for the frame, not sure about the roof.
---

 

PokyBro, great, useful pics. I too have wondered about upward strength of the screws. We have the old factory built tube style rack. The tube wall thickness is impossibly thin but fact is, it has held. I think though if I was retrofitting, I'd thru bolt to a board against the ceiling. Maybe positioning the towers to line up with the existing assist boards on the ceiling.

--

 

Finally, I don't remember the history of how the lift struts started. But I think it was a owner innovation, possibly discussed and displayed here, then adopted by the mfr (which placed inside then outside).

I do know there have been more than a few other owner ideas posted along the way that have been borrowed by other owners.

It starts with a thought, and it leads to a more interesting forum.

 


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#27 Northbynortheast

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Posted 19 December 2018 - 04:41 PM

I lifted my roof with a solar panel and two paddle boards on top, total weight 85lbs-ish, and found it possible but too difficult for me to want to do on a regular basis. My poor assumption here was that most owners remove all but the solar panel before lifting the roof. My thoughts and suggestions were only in regard to supporting loads with the roof lowered.
It is possible have the strength I’m talking about in a camper of this type at this price. The new Overland Explorer Camp X is a perfect example. A light weight, manually pushed up roof, strong enough to walk on!

Edited by Northbynortheast, 19 December 2018 - 04:42 PM.

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#28 klahanie

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Posted 19 December 2018 - 05:42 PM

My poor assumption here was that most owners remove all but the solar panel before lifting the roof.

 

...

 

The new Overland Explorer Camp X is a perfect example. A light weight, manually pushed up roof, strong enough to walk on!

 

Well there you go ... you're probably right and that would certainly explain the 250lbs. I'm usually the odd man, so don't, and didn't, think about that  :unsure: 

...

 

Hoping to check out their FB model this spring !


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#29 Intención

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Posted 20 December 2018 - 01:15 AM

Update.

We were able to re arrange and take about 75 lb off the roof. That leaves us with 2 surfboards (in cases, 1 long and 1 short). The roof box contains only lightweight items now (life jackets, paddle board pump etc). We also have a 1/2 full 4 gallon rotopax on the roof. I'm hoping to have someone weld me a simple roof rack for the truck (an 01 Tundra) like all the taxis have down here. That way I can move the rotopax down and maybe a couple other items. We repositioned the load closer to the rear and distributed across 3 load bars (maybe I should've gone with the more expensive aluminum bars). the flex is significantly less noticeable, just a slight sag in the soft walls in the up position. It's also easier to manage the lift, my wife can almost do it now. I did install helper struts before this trip (thx to info on these forums). It isn't feasible to unload the roof for security reasons here in Mexico.
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