New outside wooden structure: treated timber even if I'm going to paint it?

[MisterBoy]

We're renovating a large part brick greenhouse/hothouse. The wooden frame has been totally removed due to rot so a brand new wood and glass structure will be built on the low brick walls... Similar to many conservatories I guess

I know treated timber doesn't need painting but I want the wooden frame painted to look good.
Is there anything to be said for using treated timber anyway for additional protection and painting it? Any reason it really wouldn't be a good idea?

 

[big-all]

pressure treated is to help stop rot and attack but will not stop decay from wear and tear and weather
this is why you see weathered wood that has gone open grain cupped split and brittle because its not protected
in the same way your car may be galvanized but without paint will suffer

 

[MisterBoy]

So I think you're saying pressure treated wood should often be painted when exposed to weather; but should I use treated wood for this sort of project?

My only thought so far was whether you can get nicely finished treated timber as easily since this will be exposed inside and out?

 

[^woody^]

Paint is the protection. Treatment is not required, that's for bare exposed timber.

 

[johnny2007]

I always use pressure treated wood for exterior projects and dip the ends if cut.
It can be painted, stained or whatever you want.
For a smooth finish, wear a good mask and goggles, light sand the wood, then 2 coats of solvent based varnish (coloured if you like).
Before last coat, again sand it smooth and finish it off.
Anything else will not last.