Basement Floors Going In
That red stuff is the fancy underlayment that they put down before the floors. They're starting in the southeast corner and hopefully by the end of today they'll have most of the floor installed. The basement will be totally transformed once these floors go in - and will feel A LOT more finished and useable.
The underlayment itself is made up of 3 layers and is called the Roberts 3-in-1 Harmony Underlayment. The bottom layer is a permeable layer that keeps moisture down, the second layer is this thin section of little styrofoam balls that provide some bounce, noise deadening - and most importantly - the ability for any moisture that is underneath to travel through this layer and out the sides. The top layer is a vapor barrier that keeps any and all moisture out from the bottom of the boards.