PS,which named polystyrene,was the best alternative to wood 

Plastic Polystyrene Spa Skirt Panel Features;

1.Good property:waterproof,damp-proofing,moth-proofing,mildew-proofing,UV-proof,fire-resistant

2.Good surface feeling(the same like wood),can be sawed,planed.glued,nailed,recycled

3.Customized shape:easy-installation,maintenance-free,long-life to use(up to 20 years)

4.Green,Eco-friendly,Environmental products

5.Rohs certificate and USA-ASTM

6.Upto 10 years and maintance free