Lots and lots of clay and brick and stone at first! Bright airy houses that let in the warmth and sun and sea air. Almost everyone had rooftop gardens, flowers, vegetables, fruit trees… More inland, lots of houses recessed into hillocks of green turf. Some architecture got more snug when they spread up north, but it was still nowhere near as cold as Beleriand. In Romenna, neighborhoods cut into the rock with elaborate water systems like Petra in Jordan. And when the major sea power age took off, more and more of that thing that Romans or Greeks did where they made ultra-hard cement from mixing it with sea-water? Or something? When they reached Andunie with its steep slopes, rows of houses built into the hillside and shelves in rows of steps – elaborately beautiful tiled roofs because they were so visible to everyone on the rows above you 🙂 Around Eldanna, and back into the forests and the Nisimaldar, houses all made of wood. Wooden towns on stilts a la Laketown down in Hyarnustar! Very few hilltop towns or walled cities in Numenor, for there was no war.

As time when on more and more vaguely art deco and irregularly ancient/modern mixtures that are unlike anything IRL, weird combos like solarpunk-ish-but-also-like-really-old-Venice?

In the later times everything got bigger, heavier, and more ostentatious in their architectural cues arising from cringey societal stuff a la Real Life fragile-macho-esque imperialist powers. An increasing presence of monuments and other symbolic structures bearing resemblances to massive ancient empires…like Egypt and its giant tombs and huge proclamations in rock – My name is Ozymandias, King of Kings. The architectural expression of gravity and the amount of painstaking, plaintive, all-consuming depth of feeling and attention and time and care that went into this uncomfortably jars (or oddly resonates?) with dwellings and public spaces built lavishly desperate and over-the-top with a frantic undercurrent of self-deluding and self-congratulatory and distracting existential panic, like the rest of their society, slathering themselves in dick-waving displays of stolen ‘exotic’ materials and rare expensive decoration to make up for their feelings of bereft helplessness.

In Ar-Pharazon’s reign, engines and steam and industrial production sprouts up extremely fast, extremely zealously, without any gradual shift from the imposing pre-modernness, so that to a RL person’s eye it would be a stew of anachronisms. Though really, the styles and infrastructure and technology etc probably could eventually be reformed and fixed up to grow together into a viable self-supporting system if given enough time, but……..