Sherry,
thank you for your comments!
No heating cables - this is my laptop cable on the desk in the laundry room, I put the lettuce on it temporarily to take a picture
(My laundry room serves as my home office and seedlings nursery
)
My father-in-law had a sketch, but he is not sure where he put it... he says he'll try to find it
The basic measurements for each section are 8' or 6' long, 4' wide, and 4' high at the highest point - we put 3 sections per raised bed (4x22'), two 8' and one 6' sections.