Maximum FWC Advised Load Weight On Roof...Up or Down

[Wallowa]

I have read for sometime that the maximum load weight 'allowed' on a FWC roof that is in the up position is 1,000 lbs.

But is there maximum allowed/ recommended by FWC roof load weight when the roof is down and latched?

Thanks...

 

[Jon R]

I have read for sometime that the maximum load weight 'allowed' on a FWC roof that is in the up position is 1,000 lbs.

But is there maximum allowed/ recommended by FWC roof load weight when the roof is down and latched?

Thanks...

I read my 2021 Grandby manual and could not find any actual ratings or recommendations expressed in numbers. Even for the optional permanent aluminum rack they say “for light weight items,” and they show examples of one canoe or two small kayaks. I remember being told 150 lbs max for the Yakima tracks but can’t find that in the manual. I don’t recall seeing anything about an allowable snow load. They do say clear off any snow before lowering the roof.

Are you talking about distributed roof load like snow or are you talking about extra items like solar panels and kayaks on a rack, etc?

I can’t imagine they’d say 1000 lbs is ok with the roof up.

 

[Wallowa]

I read my 2021 Grandby manual and could not find any actual ratings or recommendations expressed in numbers. Even for the optional permanent aluminum rack they say “for light weight items,” and they show examples of one canoe or two small kayaks. I remember being told 150 lbs max for the Yakima tracks but can’t find that in the manual. I don’t recall seeing anything about an allowable snow load. They do say clear off any snow before lowering the roof.

Are you talking about distributed roof load like snow or are you talking about extra items like solar panels and kayaks on a rack, etc?

I can’t imagine they’d say 1000 lbs is ok with the roof up.

Waiting for definitive update from FWC....but a few years ago Stan stated that the roof could support a load of 1,000 lbs when up....yes as in snow load when camper is in use and top is up...sure distribution of that weight plays in but how is unknown...

That is why I asked this question concerning verification of maximum load possible/recommended on a FWC roof....notwithstanding the model differences in surface areas....preloading the roof with panels or gear would of course factor into when a roof reaches or exceeds it's load limit.

This from FWC website but only infers that the 1,000 lb snow load would be when top is up.

"How much weight will the roof hold?​

To avoid and possible joint separations or leaks, we build each camper with a “one piece” aluminum roof skin.
To maximize the balance of strength and weight, the roof frame is constructed of welded aluminum.
The roof is designed to withstand up to 1,000 lbs. of an evenly distributed snow load.
When carrying luggage, coolers, kayaks, canoes, etc. on the roof, we recommend keeping the total gear weight around 100 lbs. or less. The less gear that is on the roof, the easier it will be for the customer to raise & lower the roof.
We offer several roof racking systems to meet most customer needs."

 

[buckland]

I sure as shooting would not want to sleep under a 1000 pounds of snow... correction...I couldn't sleep. I have seen folks 8x10 tarp on roof at night and when covered with snow pull it off to the side. If it ices up it slides off better than tangled up with the Tracks/bars/panel etc

 

[rubberlegs]

We rarely get snow at home, but a couple years ago had several inches of wet snow. I forgot the snow was up there, and tried lowering the front. The overwhelming weight almost caught me between bed and roof! Oy.

 

[DesertDog]

Similar discussion here:
Snow broke my roof

Given a Hawk has about 70 sq ft of roof, this equals to an allowable snow load of 14 lb/ft3. A quick Google check list light fluffy snow as l as 5 lb/ft3, heavy snow at 15 lb/ft3 and up to 25 lb/ft3 for wet snow.

 

[Wallowa]

Tarp fine if you can place it correctly, tie it down securely and then successfully pull it off a FWC with the top up and loaded with snow....I can't....too old to fight that.

Agree that lowering the top with any "excessive' roof load is asking for trouble; distorting top sheet/structural supports, damage to internal supports or banging the crap out of you as it falls....that is why with two Zamp solar panels [350w] on Yakima rails and two power vents I always clear the snow off before lowering the top...pain in the butt to climb ladder, scrap off snow but really the only safe option for me....even with out snow raising and lowering is a grunt and stronger struts have helped but not easy with the permanent load weight on my Hawk. Just the price of recreating in snow country.

 

[Wallowa]

Similar discussion here:
Snow broke my roof

Given a Hawk has about 70 sq ft of roof, this equals to an allowable snow load of 14 lb/ft3. A quick Google check list light fluffy snow as l as 5 lb/ft3, heavy snow at 15 lb/ft3 and up to 25 lb/ft3 for wet snow.

As I recall you also possibly had pre-existing internal frame issues/weakness that contributed to the damage?

Agree that too much snow weight can end badly; hence preventative snow removal as often as is needed. When to remove snow load? Totally subjective evaluation, but can't be "too often". Middle of the night is a pain but alternative is worse.

 

[Jon R]

According to the interwebz, fresh snow ranges from 3 to 12 lbs per cubic foot (50 to 200 kg per cubic meter for you metric types).

My Grandby roof is roughly 12 feet by just over 6.5 feet, so about 80 square feet. If it’s “Cascade concrete” at 12 lbs per cubic foot, then a 6 inch accumulation would be nearly 500 lbs. Personally I would try not to let more than about 4 inches of heavy snow accumulate. If it’s super dry fluffy stuff a foot is probably less than 500 lbs total.

Being mostly a fair-weather camper, I have a fairly strong snow protection system.

Edit: I just noticed that Desert Dog already posted a range of densities for snow. Sorry for the repeat of similar info.

 

[goinoregon]

We rarely get snow at home, but a couple years ago had several inches of wet snow. I forgot the snow was up there, and tried lowering the front. The overwhelming weight almost caught me between bed and roof! Oy.

wow, that all makes sense AFTER you have gone thru it....

 

[Wallowa]

Still no real answer to the maximum weight allowed on the roof of a FWC when the top is down or up.

1,000lbs seems to be the limit when up but what is maximum roof load when top is down?

 

[rubberlegs]

I would hazard a guess for when the roof is down, but don't trust it. When it's up, it's only supported by the front and back end. When it's down, the weight is distributed along all four edges. So my hunch is it can handle it better with the roof down. I'd have to study the frame to make a better guess, but I'm retired from that stuff!

 

[Wallowa]

I would hazard a guess for when the roof is down, but don't trust it. When it's up, it's only supported by the front and back end. When it's down, the weight is distributed along all four edges. So my hunch is it can handle it better with the roof down. I'd have to study the frame to make a better guess, but I'm retired from that stuff!

Agree with premise, FWC's 1000 lbs is maximum load applicable when top is up as stated on their website. Perhaps this limit also applies when the top is down, notwithstanding more support when down.

My question is exactly that, is the listed 1,000 lb limit also the limit when the top is down?

Moot point for me. If the snow load can't be removed and becomes more than a few hundred pounds added to my fixed roof weight I will not be able to successfully lower the top without tweaking it. Once successfully down I would like to know the weight limit if I still can't remove an accumulating snow load. Unfortunately determining the actual snow load weight is a total WAG so not sure how to use the load limits recommended by FWC. Experiential learning?

 

[Occidental]

We definitely reached what I feel is the maximum load on a trip through the Great Lakes in the spring of 2023.

It was somewhat of a surprise storm coming off of Lake Superior (the storm wasn't a surprise, but that intensity and gradient of accumulation close to the shore definitely was). I blame it on Gordon Lightfoot passing away on that day. I'm convinced that Lake Superior was saying goodbye to him.

As an example of the measure of the extreme weather, when we found a 'shelter from the storm' the owner of the campground we stayed at assured us she had never seen the local school close, and we would wake up to open roads and clear sailing, well, the school closed the next day and there was about 4 feet of roadside snow when we got out about 11 am.

I'd like to say I would get out and clean off the roof at a certain threshold, but when huge ice bombs are falling on you, and you have no idea when it will quit or even give you a break, making the right decision becomes a bit tougher than 'in theory'. I ended up dropping one end of the camper at a time, scraping off the wet sticky snow, raising it back up (I think my back still hurts) and then moving to the other end. It took us about 2 hours of cleaning off snow that morning before we could hit the road. In an hour of driving there was no snow, and rain was the weather of the day. Oh the glory of the Great Lakes.

I don't know about the total weight on the roof. And I don't know if I could have removed it in the dark. But the 4WC held up, without damage, as it always has.

 

[DesertDog]

Anyone have a picture of a stripped roof showing how the lateral ribs are connected to longitudinal ribs?

Answer to OP question will strongly depend on whether the lateral ribs are welded to longitudinal ribs or bolted/riveted together. A proper welded assembly (welded all-around at each junction) will significantly increase capacity when supported across the shorted distance between the side walls. If the lateral ribs are pop riveted in place (two per junction) between the longitudinal ribs, then load capacity may be no greater in down position than in up position.

 

[Vic Harder]

i'm pretty sure none the factory framing is welded all around, since one of the unique features of these campers is their ability to flex...

 

[Wallowa]

Pretty certain the frames are welded, TIG I believe...fairly certain they have structural engineers that have calculated the loads with these frames....so the snow load maximums are design values and perhaps actually tested to failure.....whatever, the construction is what it is and the recommended snow loads up or down should be available. The 1,000 lb max when up is only half of the answer.

 

[Wyo4Life]

I would never even consider putting that kind of weight on top of the camper, up or down. If you got caught in a snowstorm that is one thing and I would do everything I could to clear the roof as much and as quickly as possible.

 

[Wallowa]

Wyoming,

Of course removal is best, but keep in mind your champaign powder weighs nothing....get caught away from the camper or even overnight with a heavy snow/ice buildup occurs and removal could come too late....and dropping it damn near impossible once a serious load exists.

Wild card is nobody can accurately estimate the water content and total snow load currently on a FWC top. So my question as to design limits is really a moot one. Do the best we can and hope for the best..

 

[ckent323]

Anyone have a picture of a stripped roof showing how the lateral ribs are connected to longitudinal ribs?

Answer to OP question will strongly depend on whether the lateral ribs are welded to longitudinal ribs or bolted/riveted together. A proper welded assembly (welded all-around at each junction) will significantly increase capacity when supported across the shorted distance between the side walls. If the lateral ribs are pop riveted in place (two per junction) between the longitudinal ribs, then load capacity may be no greater in down position than in up position.

There is an older Grandby roof frame at the following link. It looks welded to me.

FWC Four Wheel & Truck Campers (projects) | (GONE) Anyone need a roof frame from an old grandby | Facebook

(GONE) Anyone need a roof frame from an old grandby? It’s just under 119” long. Free if of use to anyone. Located in Thornton CO.

www.facebook.com

In post number 8 of the following link there are a couple of roof frame images. Thaey also appear to be welded.

drilling into roof question...wierdness?

Greetings. I just made alll my connections with my solar setup and the little red light on my controller says Charging! Learned alot here on the forum and just basic electric workings and equipment. QUESTION: I am securing the panel to the roof and have my brackets lined up with the strips...

www.wanderthewest.com

If you do a google search on FWC Frame you may find other images.

I hope this is helpful

Craig