I will answer 2 questions for me I found here:
The window frames made by PVC or plastic are a bit shiny - at least the ones I bought. They did not have others at that time. But it is not much really - or at least it does not disturb me at all. And they are soooo easy to clean and the color does not change, which is important. I remember some years ago, when they made the first window frames in PVC - they turned yellow with black spots ( like the cheap plastic furniture for the garden), but I assure you, that this has not happened to my windows and they look the same as when I bought them. And I have no noise, no bugs and no water coming through.
As for the roof we made of treated wood. I cannot say, how the wood is treated. Here they say : madera tratada .. It is imported I know .. We NEVER had any problems with termites or bugs any kind. We have made other things of treated wood with the same good result. We buy the wood at Ochoa in Santiago. They have a special place, where they only sell wood ( cannot remember where it is)..
Using Caoba (Mahogany) is really not at all so sure that you will never get bugs? It might take longer, but the ?carcomas? might as well eat Mahogani ..And the quality is not as good as years back? They recommend the use of Canadian oak and it is expensive.
I know there is another wood here in Dominican - the popular name is Amarre or something like that. It is only possible to work with the wood when it is fresh. If it dries it gets so hart, that your saw will break. They used it before to make stairs for example. It is rare and I don?t know if it is prohibited to cut these trees now. But it is very strong.