By that we really mean Esrolian, since over 60% of the human population in Kethaela are Esrolian. Air-dried clay bricks, thatched roofs, with wood frames are the traditional building materials for Esrolian farmers. Walls are then whitewashed with lime. This is pretty much the same techniques that Colymar used and I doubt in most villages it has changed much.
But Nochet, Rhigos, and the other cities are different. The queens build with fired brick and stone. Roofs are tiled with ceramic tiles or even copper plates. Plastered walls get painted with frescos. And these cities have crafters – stonemasons, brickmakers, sculptors, painters, you name it. For really complex stonework, the queens can always hire Sartarites or even dwarfs. With the Opening of the Seas, these cities are exposed to the rest of the world – and so we might find crafters from Teshnos or Fonrit.
These cities are old – all date to at least the Second Age, and several have been continuously inhabited since before the Dawn. Nothing is planned, all develop organically. Some parts of Nochet are truly ancient, and were built by gods and demigods. More modern construction is piled on top of the ancient.
But those without wealth or power still use traditional techniques. So next to marvelous stone temples with painted statues and copper roofs are mud-brick buildings piled up two or three stories. If poorly maintained, these buildings collapse, which no doubt happens from time to time.