Hi @dreeped,
It looks like there is already a coating on the timber. Did the retailer happen to mention whether there was already a coating on the timber? Wax, oil or a light varnish, maybe?
If you run your hand over the surface, can you feel any of the texture of the timber? Or does it feel completely smooth?
Without knowing what this coating is, we'd have to assume that anything painted over it would not stick, meaning it would need to be removed using a combination of a suitable stripper and sanding.
Once it is back to bare timber, you can apply a suitable sealer. As it will be stored outside and will get 3-5 hours of sun, you'll need to use an exterior-grade product that is UV-resistant.
You could use either an oil or a varnish, depending on what finish and level of protection you are looking to achieve.
An oil, such as Feast Watson Clear Outdoor Furniture Oil would be suitable if you are looking for a lighter coating that will retain the natural feel of the timber, noting that reapplication of the coating and some annual maintenance would be required.
An exterior grade varnish, such as this Bondall Satin Monocel Gold Marine Clear Timber Varnish would also be suitable. It will form a film on the surface of the timber, which will remove the natural feel, but it will also last longer and require minimal maintenance when compared with oil.
Either option will work, with varying levels of maintenance required and slightly different looks and feels. Personally, I like how varnish looks and am a fan of low-maintenance options, so it ticks my boxes, but ultimately the choice is yours.
Let me know what you think and if you have further questions, please don't hesitate to ask.
Jacob
