What percentage of the total length of side property lines on which a firewall may be constructed on R-3 zoned properties allows for two side firewalls?

On R-3 zoned properties, local building codes typically dictate that the construction of firewalls is permitted under specific conditions, especially those that separate two structures. In the context of the question, the percentage mentioned relates to the allowable lengths of side property lines on which a firewall can be constructed.

In many jurisdictions, a common requirement is that a significant percentage of the total length of the side property lines be available for the installation of firewalls. The correct answer reflects a common regulatory standard, suggesting that for two side firewalls to be permitted, 85% of the total length of the side property lines must be usable for their construction. This high percentage typically considers the need for fire safety, minimizing risks of fire spread between adjacent structures, and ensuring compliance with overall zoning regulations established to promote safety and minimize hazards in residential areas.

The other options suggest lower percentages that may not meet the necessary building code standards for fire safety in an R-3 zoning context, thus making the choice of 85% the most representative of such regulations.