My current small workshop has a clear plastic corrugated roof which provides an excellent amount of light during the day. There are no windows on the walls which are lined with shelves and hooks etc.

My problem is two fold. The first is that the plastic is getting a little old and has a few cracks, it should last the winter but I'm hoping to replace it in the spring. The second is that the workshop not surprisingly gets quite cold in the winter and quite hot in the summer.

What should I replace my roof with? I'd like to keep a large amount of light coming in.