I am building a pergola, live in the mountain west so cold winter, warm summer. I want to paint the pergola white so do I still need to use Redwood or Cedar or can I buy regular Doug Fir or Pine, and prime it really good. I’ve been told that I need to prime it either way, so why pay double the prices for Redwood if the primer and exterior paint will seal the wood from weather and insects. Thanks for your help!!