These can be on as small a lot as 20 x 20. Siminized, each house has two bedrooms and one and a half bathrooms. In RL UK last century, houses of this type were built in swathes to provide replacement housing for the working classes, as the previous century's tiny terraced homes, now regarded as "insanitary" were demolished. In RL they usually had a larger garden, reflecting the "grow-your-own" philosophy that was a hangover of post-war rationing. So in your Sims, building for realism would suggest a 20x 30 lot (the extra length going backward from the street). Many of these homes had extra space built into the attic, to form a third bedroom.
The best of these houses were built using traditional methods. Later they were made as "pre-fabs" and are harder to maintain because of the construction methods, and therefore harder to obtain mortgages for, so are slowly going out of use as traditional family homes. Many of those have been converted to "flats", usually an upstairs and a downstairs flat, or "bedsits", providing housing for singles or small families.
They generally have a basement but no garages. (Unless there are communal spaces with several garages, say at the end of a street, each belonging to one of the houses.) A coal (or in those cities that already had a Clean Air Act, coke) fireplace provided heat and hot water.
Typically, in a row of what were then Council-owned or social housing, the only thing that would vary between the new builds was the colour of windows and doors.
In RL again, most of these were sold under the "right to by" legislation introduced by the Conservative Party, which finally resulted in Councils completely ceasing production and management of social housing.
They are far more interesting as individual householders make changes to them - a garden here, a dormer there, an aeriel or weathervane, an extension at the back, a swingset, a greenhouse.
Each duplex houses two families. In this case, one has been left unfurnished while the other is completely ready for a family.
Made with all EPs and SPs, the cost is §49,576
Sita March 23, 2017