I’m building a new house in Minnesota that will have a pre-stressed garage – a 3-car garage below the main 3-car garage, both 34’x26’ in size.  This lower garage has 10”x10’ concrete walls front and back, and 8”x10’ concrete walls on the side.  It’s a walkout lot, and will have a 8’x8’ insulated single garage door, and will have a standard metal exterior door for access to the lower level of the house.  

 

I want to use the lower garage as a play space for kids in the winter, and a place to store and work on cars.  

 

There’s a good chance we’ll encounter radon on our build site, and the house itself will have a mitigation system.  

 

What is the ideal way to heat, cool, and ventilate this space?  The builder suggested just a simple exhaust fan to vent any car fumes, but I’m thinking I might need both a fresh air intake and exhaust.  This space will likely be pretty air tight, so I also wonder about moisture management.  

 

Thank you.