Hello All,
I haven't posted for a while due to being super-busy. Anyhoo, a coupla three weeks back the drain tube for my AC let go and filled the driverside front and rear floorboards with water during an extended highway trip. I replaced the drain hose and disassembled the interior, parked the car in a dehumidified garage and placed a box fan blowing down into the car through the sunroof to dry things out. The car has been used minimally and spent most of the past two weeks like this. The floors have been looking very dry for the past week. I started to reassemble the interior last night and was very suprised to find I could still squeeze a slight amount of water out of the glued down asphalt type underlayment in the drivers footwell. Being curious I started to pick at the underlayment. It appears to be a layer of asphalt/rubber stuff with a fabric top and a thin foam layer underneath. It is glued down with some pretty aggressive glue. The more of this stuff I pried up the more water I found! Turns out the foam base holds water really well and the thick asphalt top layer basically prevents any type of evaporation. I ended up scraping all of this underlayment out of the footwell with a stiff putty knife. It took about 2 hours. There are hidded depressions in the floor sheetmetal to add stiffness and they were filled with trapped water! There is no way this water was going to evaporate being covered with a layer of foam and asphalt. This product seems like a very poor choice for a floor area that is sure to get wet at some time in the life of the vehicle. I recommend that if you have ever had a leak in your car and you have this 1/4" thick underlayment glued to the floor in the front footwells that it be removed immediately. This may seem like a radical departure to some but trapped water, especially water that is completely hidden, can do enormous damage in a very short time. I am planning on removing the passenger side underlayment as well as a preventative measure. I have not noticed any increase in cabin noise as a result of removing the stuff but I am planning on spraying undercoating or an audio product like Dynamat or Roadkill on the metal when I get a chance. I will likely also add a layer of carpet padding under the mats for additional deadening. Since the rear footwells are plain metal I cannot see any disadvantages to removing the nasty stuff. If my car didn't dry out in a dehumidified garage in two weeks time I can imagine how long it would take under worse circumstances. I hope this helps someone. RT

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