Pillars for the terrace, laminated wood or treated (plastering)

[addee]

Hello,
I'm planning to build a terrace. I will use 160x160 posts, which I will probably cover with cement board and plaster. I'm considering using spacers for the cement board, such as 5mm spacers, to create an air gap. Possibly having it open at the bottom and weather-protected at the top or using some air vent.

I'm leaning towards laminated wood instead of pressure-treated wood? Opinions?

Or should I use pressure-treated wood if I'm going to cover it anyway? If I cover it and it's pressure-treated, do you think I should wait 1 year for it to air out before attaching the cement board? I assume to minimize movement if it dries out.

 

[addee]

I now see that I need to upgrade the beams to 42x180 as it seems. Too bad, since I only have 150mm (minus 28mm) if I'm going to place them on the existing cast slab for the balcony.