Weight on a Class C roof

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