My hubby very kindly made a coldframe for me. It’s a first for us. Our neighbour gave us a large piece of double glassing. Size wise it was 40″ x 30″ we bought some planks from the local merchant. Mark cut 4 bits of 40″ and 4 bits of 30″ and then screwed the planks in some uprights.
You can click on the picture to enlarge.