Interesting. After reading this, I was outside at work replacing some glass on one of our much older greenhouses and saw the initials 'L+B' on a glass-plate retainer (glass shingle roofs) and found a nameplate in the corner which said 'Lord and Burnham', and I think it had a certificate or code number '5xxxx'. It was pretty tarnished, and these houses are pretty old. They would have been very nice in their youth, with top hand-crank venting plus side vents, and top vents on all the connecting structure between houses. before computer control systems, many people were employed to open and close vents and control heating. nowadays the ones that haven't had the glass taken off and replaced with double inflated poly roofs, are leaky and dangerous to be in
