Hi @Revi,
Thank you for your question about what to use for an outdoor timber shelf.
When you say outdoor, how exposed to weather, particularly rain, is this shelf going to be? The level of exposure to rain will be the key point in selecting a material for your shelving project.
If it is well covered, then there is nothing stopping you from using the CUSTOMpine 1800 x 595 x 16mm Carcass Shelving E1L White Standard Particleboard that you've photographed above. Melamine is a good option as it is prefinished and looks nice and clean. In saying this, melamine is a coated chipboard material that is not good if it gets wet. If water gets into the cut edge without any edge banding, then the core of the material will swell and distort, leaving you with a warped material that will eventually break down.
Plywood is another good option. It is more resistant to swelling, although it will still swell if water gets into it, just not as severely as melamine. If you chose to use plywood, you would need to seal it using something like an exterior paint or exterior varnish.
Depending on the size of shelves you require, you could also use something like this 285 x 19mm DAR Pine, which is timber in the same way as plywood, but it is milled to size, rather than shaved and glued together like plywood is. Retaining the natural structure gives it more strength than something like plywood or melamine which are engineered products. Similarly to the plywood, you would still need to coat it in something like paint or varnish to protect it from water ingress.
Any of these options would work, with varying degrees of effort and likelihood of issues. Let me know what you think, and if you have further questions, please don't hesitate to ask.
Jacob
