I'd like to cover this space, but no idea how

We have a kind of alley way that leads from our back door, along the side of the house, and into the garden. The house is ours, and the opposite wall is the side of our neighbour's single skin garage. I'd love to put something over this area, just under the house tiles, to keep this area dry, so that it can be used for more than storing the bins. Not talking about it being an enclosed space, just somewhere we can maybe put walking boots, maybe our two bike, some gardening equipment on the walls, etc, and they need dry.

Any advice, pictures, suggestions, etc? Thanks in advance.