Here is how I fixed the hot floor problem in our Class C motorhome. This is a common problem in many Class C or Class A motorhomes that have the engine in the front of the RV. If not properly insulated (which they normally are not) the passenger side floor gets very hot during long drives and becomes very uncomfortable for the passenger and often the driver.
The fix for this problem is relatively simply and anyone can do it.
Materials You Will Need For This Fix
Thermo-Tec 24" X 48" One Sided Thermo Guard Heat Shield
One of these rolls should be enough for one side of your cab area. I purchased two rolls and covered both the passenger side and driver's side floor and exposed areas underneath.
3M Foil Tape 3381 Silver 50 Yd
This tape did a good job holding the heat shield in place. In the engine compartment it should hold up fine and withstand the engine heat.
Applying The Heat Shield
Place the heat shield material "foil down" on the area of carpet you will be insulating. Using a pen or sharpie, trace a pattern on the heat shield. Use a scissors to cut the heat shield material. Then lift the carpet and slide the heat shield under it. Use strips of metal tape to hold the heat shield in place. Repeat this process for the exposed areas underneath the cab as well. This area will be a little difficult to reach so do your best. It won't be visible so no need to keep it pretty.
Other Things to Check
When replacing the engine cover inside the cab area (a.k.a "Dog House"), make sure it is snugly in place and that all of the engine cover seals are closed. Wires or other materials under your dashboard may have gotten caught up in the opening before reinstalling it. So check for that before reinstalling it and you'll prevent any unexpected air/heat leaks.