Looking for a lightweight board that can withstand load

[Genvägen]

We have a caravan, and we are now looking for a building material that increases the weight minimally.

In the caravan, there is a bunk bed with very narrow beds.
My idea is to widen these from 60 cm to 80 or 90 cm.
Getting wider mattresses is easy, but I need to build a bed base or board that extends 20-30 cm beyond the 60 cm bed.
It should be able to support 80-100 kg of weight both when sleeping and when sitting on the edge of the bed.
My hope is that the board is also thin, so there is still enough height in the bed.

Looking forward to your best solutions.

 

[TypRätt]

Titan! 😁

 

[Matti_75]

Plywood but it doesn't become very thin.

 

[Trappa]

Plywood but it won't be very thin.

6 mm durkaluminum

 

[Genvägen]

Thank you for your input so far.
My hope was to find a solution with even less weight.
Maybe some strong or reinforced styrofoam or some smart moldings, who knows...
Most of the caravan is otherwise factory-built from 4mm veneer boards and "studs" that are about 3cm, this to keep the weight down.
I realize that a bed base in these materials will be difficult with my circumstances, but I'm happy to hear more of your ideas.

 

[Plupp 618974]

Aluminum profiles or fiber-reinforced plastic.

 

[Genvägen]

Aluminum profiles or fiber-reinforced plastic.

Welding a frame and truss with aluminum profiles could be an option.
What type of fiber-reinforced plastic are you thinking of? I'm googling, but can't find anything suitable.

 

[Plupp 618974]

Welding a frame and truss with aluminum profiles might be an option.
What type of fiber-reinforced plastic are you thinking of? Googling, but can't find anything suitable.

Carbon or glass fiber. Don't do it. Nasty chemicals, and carbon fiber ends up in landfills as I understand it.