Most homes are made of brick and wood
Most homes today are made of asphalt, fly ash, and a mixture of sawdust and wood glue, with a minimum of actual timber, all of which is concentrated in the framing.
Roofing tiles are grit in asphalt. They're laid over tar paper. That's laid over chip board, which is just crappy bits of wood stuck together with the part of wood which generates dioxin when it burns. All of the structural members are held together with galvanized metal ties which emit zinc when they're heated much. The wiring is required by code to be sheathed in PVC which releases dioxin and chlorine gas when it burns. The outside of the house is covered in more chipboard which is covered in recycled milk jugs which is covered in some more manufactured wood, maybe some thin plywood siding, more of that dioxin-producing glue. The inside of the house is covered in sheet rock made from fly ash from a coal plant, and you hope their scrubbers are working right or it's full of toxics and radioactives. Carpets are one plastic or another which usually produces all kinds of nasties when it burns, or sometimes a natural fiber treated with some kind of toxic fire-retardant coating which often releases chlorine gas. Most padded furniture, likewise.
It's clear that a submarine is a sketchier environment for a fire than a house, but it's also clear that pretty much everything in the modern house is both flammable, and toxic when it burns.