low profile storage shed are built with double wall panels to resist dents. The panels are made to exacting standards for a snug fit and solid construction. Many come with paintable steel doors for extra security and long service life. Best of all, the entire structure is impervious to practically all weather extremes and virtually maintenance free.
If you want to go a step further and separate your tools, you'll need to get a bit more creative. One way is to utilize PVC pipe to make containers for your tools by attaching to two pieces of wood and hanging that from the wall. Another solution is to utilize a pegboard for your larger items as well, as they can hang from hooks similarly to smaller items.