Hi guys
I need to prepare a box kick board like shown in the image below (white one). I bought his and its height is 250mm. This is making my vanity sit low. I need to have at least 300mm height box kickboard to be made. Custom built are about available.

what timber from Bunnings I can use to make kick board of 300mm?
I looked into these timbers but i have to be careful about water penetration as well.

the vanity I am using in bathroom is 1800. hence we need to have kickboard to support the weight.
Thanks