Weight on a Class C roof

[EdTheEdge]

Hello, This is my first post on these forums. I am not new to RVing as I have owned an rv since June 2013. I bought a Thor Chateau 22e new at that time. I go out once a month at least but more often twice a month. I love RVing but even after 4 1/2 years of using "HaRVey" I am still learning things. So here is my first question:

How much weight can a Class C roof withstand? I am 6'4" and weigh 240lbs. I would like to climb up on top to do some maintenance, mostly to wash the roof and clean the fan housings but I fear that I may be too heavy and dont want to damage anything. I'm a very cautious guy so I wanted to ask the experts here before I venture "up there".

TIA,
Ed

[EdTheEdge]

Thanks for all the tips! Much appreciated!! I am going to do as much as I can with an extension ladder. I got a pretty good reach so I might be able to get everything done without having to go up there.

[j-d]

T18skyguy wrote:
check that there are no small stones stuck in the sole of your shoes.

That, and also don't move you feet in a twisting motion with your weight on them. Can twist/distort the roofing. Instead, pick your feet up and put them back down in the direction you want to go.

And for giggles, a friend of mine went up on the RV roof and brought a plywood scrap up to support his weight. That scrap had a couple nails through it...

[Racine96]

T18skyguy, I haven't thought about this. Thanks for the advice.

[T18skyguy]

To further make Chum Lee's point, right before you climb the ladder, check that there are no small stones stuck in the sole of your shoes. They'll punch a hole right away. Don't ask me how I know this.

[Rick_Y]

My personal rule is the maximum to put on the roof is five pounds less than whatever I weigh and at least five pounds more than my wife weighs.

[Racine96]

I am 210 and my DW 140, we both walked over the roof at the same time. No problem. I was told that if the unit came with a ladder from the factory, you are good.

[EdTheEdge]

Chum lee wrote:

EdTheEdge wrote:

Chum lee wrote:
If your motor home has a factory installed ladder up to the roof, the manufacturer knows/expects you to be crawling/walking around up there once and a while. Think of the liability aspect. That said, you are a pretty big guy and the idea of spreading your weight around using plywood is valid. IMO, you'll more likely fall off the roof than through it so be aware of that. Leave the stiletto heels in the closet and wear clean flat soft sole shoes to avoid localized damage. Be aware of and avoid soft spots. The roof will more likely deflect under load long before it breaks. I'm over 200 lbs. myself and I never like the wobbly feeling of walking around up there because the MH moves around just because of my weight, not to mention the wind. Other people moving around inside or entering/exiting move my Class A around a lot, especially when I don't expect it.

Chum lee

There is a label on the ladder that states a 250lbs weight limit. Since I weight 240lbs I fear that is too close to the limit to take chances. Your thought?

I'm an engineer by trade so what I say next is my opinion and a secret just between you and me. When structural engineers post a placard like you have on you RV, they usually use a safety factor of at least 2. (when new) That said, the safety factor takes into account, time, wear and tear, stupidity, corrosion, abuse, construction defects, and other things like . . . unknown! In ten years the ladder may well pull off in your hand under your own current weight due to "unknown" factors. For floors/roofs, you need to concern yourself with whats referred to as punching shear and impulse forces as well as overall weight(live/dead load). To understand the loads, think of a claw hammer hitting a 2 x 4. A fairly light weight concentrated load hits a relatively soft object with considerable speed. That's what does the damage or drives the nail. If the hammer was made of rubber but weighed the same, it wouldn't work at all. That's why your choice of shoes could be critical as to doing roof damage or not. That's also why using a piece of plywood or other rigid panel to help distribute the dead/live load forces is a good idea to avoid localized damage. The hair always goes up on my neck when I see people using their RV roof as a grandstand while drinking and sitting in lawn chairs. Very bad idea but hey, . . . . you only live once!

Chum lee

Thanks for your explanation! I too see people lounging/hanging out on RV roof tops all the time, quite often children. I shudder when I see this.

[Chum_lee]

EdTheEdge wrote:

Chum lee wrote:
If your motor home has a factory installed ladder up to the roof, the manufacturer knows/expects you to be crawling/walking around up there once and a while. Think of the liability aspect. That said, you are a pretty big guy and the idea of spreading your weight around using plywood is valid. IMO, you'll more likely fall off the roof than through it so be aware of that. Leave the stiletto heels in the closet and wear clean flat soft sole shoes to avoid localized damage. Be aware of and avoid soft spots. The roof will more likely deflect under load long before it breaks. I'm over 200 lbs. myself and I never like the wobbly feeling of walking around up there because the MH moves around just because of my weight, not to mention the wind. Other people moving around inside or entering/exiting move my Class A around a lot, especially when I don't expect it.

Chum lee

There is a label on the ladder that states a 250lbs weight limit. Since I weight 240lbs I fear that is too close to the limit to take chances. Your thought?

I'm an engineer by trade so what I say next is my opinion and a secret just between you and me. When structural engineers post a placard like you have on you RV, they usually use a safety factor of at least 2. (when new) That said, the safety factor takes into account, time, wear and tear, stupidity, corrosion, abuse, construction defects, and other things like . . . unknown! In ten years the ladder may well pull off in your hand under your own current weight due to "unknown" factors. For floors/roofs, you need to concern yourself with whats referred to as punching shear and impulse forces as well as overall weight(live/dead load). To understand the loads, think of a claw hammer hitting a 2 x 4. A fairly light weight concentrated load hits a relatively soft object with considerable speed. That's what does the damage or drives the nail. If the hammer was made of rubber but weighed the same, it wouldn't work at all. That's why your choice of shoes could be critical as to doing roof damage or not. That's also why using a piece of plywood or other rigid panel to help distribute the dead/live load forces is a good idea to avoid localized damage. The hair always goes up on my neck when I see people using their RV roof as a grandstand while drinking and sitting in lawn chairs. Very bad idea but hey, . . . . you only live once!

Chum lee

[EdTheEdge]

DrewE wrote:

EdTheEdge wrote:

There is a label on the ladder that states a 250lbs weight limit. Since I weight 240lbs I fear that is too close to the limit to take chances. Your thought?

Assuming the ladder is in good shape, I would not fear to use it with care if I were you. It would be within its specifications. Like most safety critical items, the weight rating incorporates a safety factor--googling suggests it's 3 usually for ladder weight ratings, so a ladder rated for 250 pounds should support 750 pounds without failing (but one still ought to follow the official ratings, of course).

I actually walked on the roof when I picked up the RV from the dealership as part of my walkthrough. It seemed to be rather solid. That was 4 1/2 years ago. Haven't been up there since. I think I will just get a long extension ladder and use it to reach where I can to complete my maintenance. Hopefully that will suffice.

[DrewE]

EdTheEdge wrote:

There is a label on the ladder that states a 250lbs weight limit. Since I weight 240lbs I fear that is too close to the limit to take chances. Your thought?

Assuming the ladder is in good shape, I would not fear to use it with care if I were you. It would be within its specifications. Like most safety critical items, the weight rating incorporates a safety factor--googling suggests it's 3 usually for ladder weight ratings, so a ladder rated for 250 pounds should support 750 pounds without failing (but one still ought to follow the official ratings, of course).

[EdTheEdge]

Chum lee wrote:
If your motor home has a factory installed ladder up to the roof, the manufacturer knows/expects you to be crawling/walking around up there once and a while. Think of the liability aspect. That said, you are a pretty big guy and the idea of spreading your weight around using plywood is valid. IMO, you'll more likely fall off the roof than through it so be aware of that. Leave the stiletto heels in the closet and wear clean flat soft sole shoes to avoid localized damage. Be aware of and avoid soft spots. The roof will more likely deflect under load long before it breaks. I'm over 200 lbs. myself and I never like the wobbly feeling of walking around up there because the MH moves around just because of my weight, not to mention the wind. Other people moving around inside or entering/exiting move my Class A around a lot, especially when I don't expect it.

Chum lee

There is a label on the ladder that states a 250lbs weight limit. Since I weight 240lbs I fear that is too close to the limit to take chances. Your thought?

[Chum_lee]

If your motor home has a factory installed ladder up to the roof, the manufacturer knows/expects you to be crawling/walking around up there once and a while. Think of the liability aspect. That said, you are a pretty big guy and the idea of spreading your weight around using plywood is valid. IMO, you'll more likely fall off the roof than through it so be aware of that. Leave the stiletto heels in the closet and wear clean flat soft sole shoes to avoid localized damage. Be aware of and avoid soft spots. The roof will more likely deflect under load long before it breaks. I'm over 200 lbs. myself and I never like the wobbly feeling of walking around up there because the MH moves around just because of my weight, not to mention the wind. Other people moving around inside or entering/exiting move my Class A around a lot, especially when I don't expect it.

Chum lee

[fourthclassC]

Just a quick suggestion regarding boards to distribute the weight. Rounded corners may be better here.

[ron_dittmer]

kerrlakeRoo wrote:
If what you need to reach cannot be accessed from a ladder on the sides, you can use a small (4'x4') piece of luan or plywood to spread the weight over a larger area, but with the manufacturers constantly looking for ways to build these units cheaper and lighter, I would try to avoid too much time or movement especially on any manufacturers entry level product lines.

I Totally Agree with kerrlakeRoo.

I do feel that a 5/8" thick plywood board about 2.5 feet square will suffice. I would cut 2 pieces and screw on a simple screen door handle in the middle of each to maneuver one while kneeling on the other.

Home improvement centers sell broken sheets of plywood at greatly reduced prices. I think Home Depot even offers a cutting service. Plywood will be stronger and lighter to handle than chip board or particle board. They can get wet and dry fairly quickly if stored indoors.

This is the type of screen door handle I am referring to.