Interior Walls

Hello all,
Here again with some questions on the interior of my build. I was planning on using FRP since it's white and makes it look bigger, besides in my older years I've become claustrophobic. You know the one at the hardware store with the grainy side and .125" thick. I've read here and there that it will get messed up with the temperature difference. I don't want plywood because I don't like the stained wood as interior. I'm still looking around for any material that will work. I've been told PVC sheets might work too. Any help will be helpful. I'm still stuck on FRP.
Thank you Carlos
Here again with some questions on the interior of my build. I was planning on using FRP since it's white and makes it look bigger, besides in my older years I've become claustrophobic. You know the one at the hardware store with the grainy side and .125" thick. I've read here and there that it will get messed up with the temperature difference. I don't want plywood because I don't like the stained wood as interior. I'm still looking around for any material that will work. I've been told PVC sheets might work too. Any help will be helpful. I'm still stuck on FRP.
Thank you Carlos