A common misconception is that basements are not permitted in laneway suites, or that they are limited to unfinished space dedicated to storage or utilities.
Fact: a fully excavated basement level is fully permitted within the current as-of-right zoning by-laws and can be much more than just a place to put your hockey bags and golf clubs.
Basements are a great option on properties that offer limited depth for a reasonably sized above-grade unit and can provide the opportunity to move items like laundry, mechanical space and other infrastructural pieces below grade to alleviate valuable area in the floors above.
While building below grade can significantly increase the usable space in your suite, it does come at a substantial cost. That said, there is always a right time, place, and application for building downward.