The building codes in many areas dictate that these floors should be insulated to R-28.5 (RSI-5.02). But experience tells us that R-28.5 of batt insulation does not ensure a warm floor. In theory, the floor in a properly insulated room should be at room temperature. In practice things are quite different; it is common to find floors that are 10 F (5.5 C) cooler than the room. Why? Because it is virtually impossible to install a fiber batt so that it is in contact with, and stays in contact with, the floor above. It is also impossible to install it accurately around bracing and bridging between joists. Unfortunately, due to voids and air spaces that allow air movement, fibrous materials do not perform to their rated R-value. (R-values are determined under ideal, still laboratory conditions.) Because air gaps usually exist between the floor and insulation there is room for cold air to infiltrate from the exterior. The cold air essentially "short-circuits" the insulation material and renders it less effective.
Some designers and builders have tried to overcome the problem with heated hotbox using a dropped ceiling isolated with a fiber batt. Heated house air is then ducted in to the space created under the floor. While this helps the problem, experience proves it does not solve it. Cold air from the outside still inflitrates and overcomes the warms air from the ducts leaving the hotbox a coldbox.
Air sealing and insulating with spray foam is the solution
Spray foam insulation expands to fill the tiniest and most awkward spaces and adheres to the floor above. Spray foam also eliminates voids and resulting air movement that have plagued generations of builders and homeowners. Thousands of floors over porches, garages, crawl spaces and cantilevers have been insulated and air sealed with spray foam. Cold floors are simply not an issue any more when insulated with Red River Spray-On's floor spray foam system.
How do we fix the problem
The first thing we do is remove the drywall and fiberglass from the garage ceiling. Next we have our duct guy remove the ducts for heating the hotbox, with spray foam heating the hotbox is no longer necessary, which will save in energy costs as well. Next we make sure all the ducts to heat the room above and the water lines are on the warm side by covering them with spray foam yet still making them accessible should the need to move or repair them ever arise. After the spray foam is complete we get our drywall guy in to come in and put up all new drywall to finish the space.