Final answer:
Single-family detached homes are typically the most unaffordable according to the RBC Affordability Measure, which compares housing costs to median household income.
Step-by-step explanation:
According to the RBC Affordability Measure, the type of housing typically considered to be more unaffordable is single-family detached homes. The RBC Affordability Measure is an indicator used to assess the proportion of median pretax household income required to service the costs of mortgage payments, property taxes, and utilities based on the average market price for different housing types. Condominiums, row housing, and semi-detached homes tend to be relatively more affordable than single-family detached homes because they generally require a lower percentage of household income to cover housing costs, reflecting factors such as scale, shared walls reducing construction costs, and more efficient land use.