Max 40% of total floor area allowed for Accessory Dwelling Unit

[Sergey S.]

Some cities in Canada have this strange rule where they do not allow accessory unit to be larger than 40% of total floor area. 

We just purchased relatively small house and going through conversion of the basement into a second unit. This rule will make us to lose approximately 100 sq ft, or one bedroom, which means it will be only one bedroom unit. In long term this is really sucks, as one bedroom unit will have less rent income, higher turn around, tenant profile will be not as good.  

When talking with the city, zoning official said that what people have done to get around that rule is a shared space in the basement for laundry/storage. 

Do you have any experience dealing with floor area restriction for the second unit and how to get around it?