Both RS-1 and RS-5 are standard single family residential zones. The difference between them lies mainly in the freedom of design and subsequent allowable ratio of floor space to lot size.
RS-1 can only be developed up to 0.6, or 60% of the lot size. There are no strict guidelines as to the design of a house.
RS-5 was created in the late 1990s to protect the characteristic of a neighbourhood and maintain certain styles and standards within an area. This encompasses newly built homes and extensions as well. So long as the designs are in keeping with the guidelines of the area, floor space can be increased in ratio from 0.6 in RS-1 to 0.7, or 70% above basement floor area. If an owner does not wish to be in keeping with the design guidelines, they may do so, but only at the lower ratio. Guidelines include design compatibility based on the character of the street and neighbourhood.
Architectural and landscape elements, choice of materials and design details need to be submitted for approval to gain a permit. There is a 'Planning Department of Vancouver Workbook' available with the guidelines.
This increase in buildable floor space and maintaining of neighbourhood standards makes the RS-5 more appealing and therefore, more valuable to buyers.
*Disclaimer: this is meant as a guideline and is not intended to be relied upon, readers are advised to verify information as to their individual needs. Source: 'The Vancouver Achievement: Urban Planning and Design' by John Punter.