How to build a platform bed out of 2x lumber
12 - 2x6 @ stud length (may be able to use less lumber if can haul long lengths)
10 - 2x4 @ 10 feet long (slats)
5 - 2x4 @ stud length (remaining slat and headboard piece)
1 - 1x3 or 1x4 @ 8 feet long
6 - 2x6 @ 79" or length of headboard
1 - 2x4 @ 79" or length of headboard
3 - 1x3 or 1x4 @ 31-1/2" - back cleats
1 - 2x6 @ 61"
1 - 2x4 @ 65"
2 - 2x4 @ 79"
2 - 2x6 @ 79"
3- 2x6 @ 79"
11 - 2x4 @ 58" (for 4" gaps in between slats - check with your mattress to make sure this is sufficient)
Please read through the entire plan and all comments before beginning this project. It is also advisable to review the Getting Started Section. Take all necessary precautions to build safely and smartly. Work on a clean level surface, free of imperfections or debris. Always use straight boards. Check for square after each step. Always predrill holes before attaching with screws. Use glue with finish nails for a stronger hold. Wipe excess glue off bare wood for stained projects, as dried glue will not take stain. Be safe, have fun, and ask for help if you need it. Good luck!
I ended up deciding to go with a cleat on the back of the headboard instead of Kreg Jigging the boards together (which could also be done). You will also need to attach the headboard to the wall to keep it from cupping forward.
Build the two side rail pieces by attaching the 2x6 upright to the 2x4 platform with 1-1/2" pocket holes and 2-1/2" pocket hole screws. Also drill 1-1/2" pocket holes on ends for attaching to headboard and footboard in later steps.
Build the "footboard" piece as shown above, with the platform top piece overexending the upright piece by 2" on ends, everything is flush on the back.
Once the sides and end pieces were made, we stained them. Then on assembly, we joined the side pieces to the end with 2-1/2" pocket hole screws.
Lay the cleats in the bed and attach to side rails with 2" - 2-3/4" long screws (you can use pocket hole screws, you will only need three per cleat). Also attach center cleat to footboard and headboard.
Set the slats in the bed frame and screw down.
It is always recommended to apply a test coat on a hidden area or scrap piece to ensure color evenness and adhesion. Use primer or wood conditioner as needed.