Commissioner Paul Belanger will issue a statement and make the document public on Oct. 15 at a community centre in Elliot Lake, Ont., the city where the collapse happened in June 2012.
Two women were killed and several other people were injured when the mall's rooftop parking garage caved in.
The inquiry heard how a steel-beam weld failed due to years of corrosion caused by water and salt penetration.
Belanger will not answer any questions about his report when it is released, but commission counsel will respond to questions.
The commissioner recently rejected a request by a former engineer who faces criminal charges related to the collapse to keep parts of the final report secret.