Q. Cold Over-the-Garage Bedroom

Q. Hey Mark,

I have a bedroom above an unheated garage. The bedroom is always cold in the winter (Wisconsin). The ceiling of the gargage is currently plywood (I assume some insulation above). The floor of the bedroom is always cold. What is the best way to add insulation given that this is in a garage? Can I add some foam board?



A. Hey John,

Insulation should have been installed in the floor of the bedroom over the garage when it was built. If not, then my concern would be that perhaps the bedroom was added without the benefit of proper code supervision and inspections. What many people don’t understand is that ceiling joists and trusses are designed to support a ceiling, not a floor. Therefore the engineering might be suspect. All that being said, and assuming the garage/bedroom was built to proper engineering standards, I would say that your best bet would be to add some solid insulation on the garage side. Please be aware that the “Styrofoam” type insulation, can not be left exposed. It too would need to be covered with drywall to protect it in case of a fire. I would also suggest checking with your local Better Business Bureau to see about finding a reputable and qualified contractor to evaluate the situation first hand. He should have an opinion on the state of the bedroom, know how to research previous home improvements and their permit and inspection records, and give you an idea of how best to proceed with your particular problem.

Hope that helps.


Mark Nahrgang is the owner of Kingdom Inspection Network Group – St. Louis and is a professional NACHI certified building inspector in the St. Louis metro area. Mark performs home inspections as well as commercial inspections throughout St. Louis and St. Charles County.