building a training room inside my gym ADVERTISEMENT 768 viewsSeptember 21, 2016 0 Kalyn September 21, 2016 0 Comments cost to build a 1500 sf cardio room 8 Answers ActiveVotedNewestOldest 0 Michelle 0 Posted 0 Comments Like the previous two answers, there are way too many variables involved, from the flooring to equipment to sound system to mirrors…You can spend as little as $500 up to $25k depending on what you want/need in there. You are viewing 1 out of 8 answers, click here to view all answers. Register or Login