The Foundational Magic classroom is less a room and more a containment chamber. Its walls are thick stone, charred in places and patched with mismatched repairs from centuries of misfires. Sturdy worktables dot the room, each surrounded by scorch-proof mats and enchanted cushions that fling themselves under falling students. The ceiling arches high overhead, blackened from stray sparks, and a lattice of bronze wards is inlaid into the beams to catch wayward spells before they hit the roof or windows. The windows are narrow slits enchanted to vent smoke instantly, and an entire corner is devoted to a large, glowing sigil etched into the floor that can be activated to nullify magic when things go truly wrong. This is where the magic truly happens! Well, it's supposed to anyway, because if you fail these classes, you're probably a squib.

This classroom is rectangular and high-ceilinged, with thick stone walls and tall stained-glass windows that depict centaurs, goblins, muggles, mermaids, and other non-wizarding creatures and peoples. When the sun shines through, the colourful figures spill across the floor in shifting patches of light, giving many students at least one thing to look forward to in this class. Rows of sturdy wooden desks face a wide blackboard framed in carved oak, its surface dusted perpetually with chalk. The floor is paved in worn flagstones, smoothed by generations of students, and echoes carry easily when lessons grow dull. Some students seem to be labouring under the illusion that this classroom is their second bedroom.

All awards bestowed upon students, staff, or even the castle itself are displayed here, ranging from centuries-old medals of academic excellence to the most ridiculous awards ever dreamed up by former headmasters. The hall is wide and rectangular, with a high timber-beamed ceiling, and stained glass windows along the walls depict the founding of Penwick. Glass cabinets line the chamber, stuffed with gleaming cups, dusty shields, and enchanted plaques, the shelves enchanted to stretch back farther than naturally possible. Despite the variety, most students care only about the Quidditch Cup and the House Cup, locked in pride of place on a raised dias at the far end of the room. Of course, with a little creativity and a healthy disregard for school rules, it’s always possible to “borrow” them for a night of house pride or mischief.

The washrooms are divided by gender, with an additional set of individual washrooms for those who prefer more privacy, or who exist outside of the traditional binary. They were last re-done as a past Headmaster's pet project, and are in a very distinctive style because of it, with orange marble floors, vessel sinks, and light wood accents. Calling them ugly would be unkind, but also quite true, and it's up to each student to decide which of these is more important to them.
The mirror in the men's washroom has shattered every November 8th since 2003, and no one can agree if it's a very shy ghost or a dedicated lineage of pranksters.