The London evidence comes from walls preserved up to half a metre in height in damp conditions. Where space was at a premium in the centre of town, the houses were separated by narrow alleys, sharing eaves-drips from the roofs and with covered drains that fed into larger roadside drains (see Drainage systems).
Most houses were probably single-storeyed but some may have had upper floors or utilised the roof space. Others had small cellars where buildings on slopes were terraced to form half-cellars, such as a timber-framed example at Regis House (KWS94). A cellar of a late 1st to early 2nd-century timber-framed structure, excavated at Bishopsgate (ETA89), was reached by a flight of stairs cut into the natural surface.
From site evidence, it has been possible to reproduce exact ground plans and the relationship of one building to another. At Poultry, the 1st-century buildings were strip buildings which varied in layout, some were double-fronted with central corridors that led from front to back (see Rogue trader & Bodger and Flog-it & Scarper in Londinium LIte).
Entry was from the main wooden boardwalk of the street and the corridors led through the houses to the back yards, which served as rubbish dumps. Other houses were constructed with three or more rooms, one behind the other, with long corridors running down the side of the buildings. Where the front room consisted of a shop, there were rarely front walls but wooden sills laid out to take removable wooden shutters.
Some buildings may have been rented out to several tenants. Behind the early Flavian forum, at Leadenhall Court (LCT84), narrow single-storey buildings, separated by narrow alleyways, included a row of rooms (4m square) all with small domestic hearths which could have been simple one-room lodgings. Similar rooms existed behind a strip building at 76-81 Newgate Street (GPO75), reached by a side entrance, and this may be similar to rows of self-contained rooms in Italy which accommodated slaves.
A late 1st-century building of a better build with shallow foundations at Watling Court (WAT78) may have been divided into apartments (see Flog-it, Scarper and sons in Londinium Lite). Finer houses like those at Watling Court, had solid floors of mortar or floors of crushed tile mixed with mortar (opus signinum).
There were also the earliest examples of mosaic floors. Black and white tesserae laid out as roundels with small crosses interspersed in a solid crushed tile and mortar floor. The solid floor was laid straight onto the earth. There was no underfloor heating system and braziers would have been used to heat the rooms. The evidence for them on other floors is revealed by burnt circles left on the flooring. Wall paintings were simple blocks of colour.