Hi Mike,
Most of the fabrics available are only coated on one side, except for the heavier fabrics in the DIY Packraft shop, and possibly some sold elsewhere. I used to have fabrics with PU coating on the other side from the TPU, but PU is not as good as TPU. You will find that most PU coatings are not airtight or waterproof and can rub off with a hot iron.