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Old 05-17-2019, 07:50 PM   #1
gatorlee1
 
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Default Water tank on top of mega roof?

I have an old valterra water tank with that crack in it I posted a few months back. I was thinking of mounting it in the roof since it's black I could have got water and throw on a gravity fed external shower.

I got to thinking it's a 30 gallon tank with almost 450 lbs riding almost 10 feet off the ground which may create some serious issues, but then again I may totally be overthinking it and it may not be an issue at all.

Just curious if anyone had any thoughts.

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Old 05-17-2019, 08:37 PM   #2
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Default Re: Water tank on top of mega roof?

As a guide what is the maximum permitted roof rack loading given in your owners handbook?

From memory it is only something like 150 lb evenly distributed, correct me if I'm wrong.

Keith.
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Old 05-17-2019, 08:59 PM   #3
OrioN
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Default Re: Water tank on top of mega roof?

MEGA roofs do not have roof rails and a very limited weight load rating (read: limited to roof vents).

You will need to add internal or external reinforcement or support structure to accommodate the tank.





.

Last edited by OrioN; 05-17-2019 at 09:48 PM.
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Old 05-17-2019, 11:11 PM   #4
ranchworld
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Default Re: Water tank on top of mega roof?

A gallon of water is 8.34 lbs so 30 gallons = @250 lbs. The Valterra tanks is only a few pounds so less weight than you had estimated. Not a good idea. Not only is it a lot of weight but as it sloshes around in an unbaffled tank it will cause all kinds of weird weight movement issues.

Do you really have a "mega roof" van? Or just a regular high roof? The mega is rare... Regardless, 250lbs moving around in a box on the roof is not good.
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Old 05-18-2019, 03:34 PM   #5
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Default Re: Water tank on top of mega roof?

MB's "body builder's information guide" goes on at length about calculating the dynamics of oddball loads.
(with worked examples)

Here's the 2007 edition: http://www.diysprinter.co.uk/referen...2012-11-07.pdf
and the 2011 as two parts:
one: http://www.diysprinter.co.uk/referen...1%20of%202.pdf
two: http://www.diysprinter.co.uk/referen...2%20of%202.pdf

As a water tank (instead of a "dead load" like spare tires) you'll be frequently hit by it *sloshing* when the van does turns, or is buffeted by side winds (such as passing/being passed by ... a truck).
Such incidents could be ... exciting.

--dick
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Last edited by autostaretx; 05-18-2019 at 03:37 PM.
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Old 05-18-2019, 03:37 PM   #6
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Default Re: Water tank on top of mega roof?

Yeah I really had a feeling, that thing was probably a bit to heavy, and thanks y'all for the support

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