This comprehensive step-by-step guide helps you build a brick mailbox yourself, potentially saving you over $300. Research local rules for mailboxes. Research. Do-it-yourself Brick Mailbox: Here is an Instructable showing you how to build your very own brick mailbox. My husband built this mailbox in one day, although he is a 20 year masonry veteran, we believe anyone can do this with the correct tools, materials, and planning. Overall, these structures are well-designed to withstand weather conditions, including heavy rains, snowfall, and extreme sunlight, ensuring safety. You will learn how to execute successful diy brick mailbox plans, ensuring a durable and attractive addition to your property. Materials Needed: – Bricks – Mortar mix – Metal.