I found this stuff on ebay called fatmat (cheaper dynamat basically) and it sounds like some pretty good stuff. My question is how far will a 100 foot roll get me(05 screw)? I was going to do the door panels of course and behind the back seat, is the floor even necessary?

 

That's more than enough to do all of that twice. I dunno what size cab you have, but I did everything but the roof with around 70 square feet on a supercab.

My advice though..... don't put the mat directly onto the door. I would put it around the back of the door panels, cutting room for the notches. I didn't do this, and now the mat likes to droop, and makes putting the door panel on a pain (same with cutting out the notch holes in the mat)

Seems now it would have been easier to just put it on the back of the plastic door panel. But yeah, 100ft would be close enough to do the entire truck, let alone the doors.

 

100 Sqft is plenty...more than enough. Couple of things...some advice. Get a butyl based deadener NOT asphalt based. Fatmat is asphalt based. Butyl base has no odor and asphalt smells just like asphalt. Second Skin Damplifier (which I used), Damplifier Pro and Dynamat Extreme are some butyl based deadeners.

Some basics when applying deadener...1. Clean the surface w/ alcohol. 2. Apply in smaller pieces vs. bigger pieces. 3. If you seem to have a problem of it not sticking...use a roller and heat gun. Heat gun especially if you live in a colder climate and trying to do this outside. Although, you can apply to the back of the door panel...I would concentrate on the inner (both sides) and outer (inside, of course) door skins, floor, overhead, back wall, etc. If you have extra...2 or 3 layers work wonders.

Good luck!

EDIT: If you don't think you'll mind the asphalt smell, go to Home depot or Lowes and get Peel 'n Seal.