When you build your own raised beds, I cannot stress enough that you must use UNTREATED lumber. You risk your health and anyone else's who shares your crops if the lumber is treated. There are chemicals in treatments that are detrimental to your health. The foods grown there will ingest the chemicals and you will ingest them from the food.
DO NOT buy treated wood.
Lumber for decking is treated with chemicals so do NOT buy that either.
Untreated cedar is the longest lasting wood, but I could not find any untreated in my area so I went to a lumber company that had spruce and fir and chose the stronger and more longer lasting spruce for my raised 4 by 4-foot beds.
Be safe and enjoy growing your own veggies this year. I'll be posting my pictures and changes for this year so watch for them.