You could also consider laser cut aluminium screens which are powder coated in a Corten look finish. We used them in our new house. Screens by Decopanel in Brisbane. We have a real letterbox made of real corten, but were worried about rust staining our floors so used the aluminium for the breezeway screens. Photos below

Although the existing plants were healthy and looked great the client wanted a new cleaner look and to make the space appear bigger.

Hi Margaret, Hope you found a great solution for your spa area! I saw someone mention using natural foliage as a screen and thought I’d chime in to propose using a mix of real and artificial plants. After all, living plants may be seasonal (and fail to offer much privacy when they’re not in full bloom). You can check out our range here - www.evergreenwalls.com.au Richard

Do you want a 'rough-cast' effect ? I can think of 2 main options -- a concrete block wall ( plastered / rendered ) but that is likely to be 200mm thick approx , plus your light boxes , which look 100mm or so . Otherwise steel poles cemented into the ground ( galvanised , probably with solid 'feet' to keep them firmly grounded -- say flat bar welded to the bottom , before galvanising ) -- at a guess 80mm x 80mm or 100 x 100 to get the required strength . Covering though would need to be powder coated panels , or maybe something like 22mm plywood . Neither are all that rough though , and would still be 100 to 125mm thick . You need a decent width and strength though -- 3 x 50kgs panels plus wind gusts means your cement panels aren't strong enough , and crack and delaminate . Do it once , do it right , do it solid .