i installed mine with the help of a body shop friend. <br><br>i had previously seen someone install theirs by making an oak frame that followed the contours of the ribs. he scribed them to the oak so he could cut them out exact. lots of work jsut to have a flat surface to mount a fan to.<br><br>when i went to my friend at the body shop and explained this, he said no need to bother. the ribs are not as high as they look. the material used to seal the frame of the fantastic fan can easily span the gap and seal it up. the screws then go through the sheet metal to hold it down. the trim piece that they give you is huge and can work with a very thick roof. once cut to size it, perfectly trims out the opening against whatever roof material you have inside. it then fastens to the main body of the fan with 4 screws so it does provide some clamping pressure.<br><br>i had the gasket from the fanastic fan and a fan installation kit from Camping World and used neither.<br><br>the star here is the material he used. 3M Windo-Weld. its what is used to install your windshield and fixed side windows on vans and cars. it is even used on some GM vehicles that have windows that tilt out, in lieu of hinges. thats right, half the window is held on by this material which when cured remains flexible to be used as a hinge itself. only other piece holding it is the latch. the stuff can also be used to attach trim and other things to a vehicle.<br><br>the 3M Windo-Weld was placed in a bead around the 14x14 opening, liberaly, then the fan/frame was dropped into place. pressure was placed on the frame to allow the stuff to squeeze out. the screws were then added, securing the frame. another bead was run around the perimeter, about an inch beyond (kept in check with blue masking tape). the stuff was also painted with a brush (another neat feature of the stuff) on top of the frame, about an inch wide again, covering each screw head.<br><br>how has it performed? today i had to add a little more of the stuff to the rear side of the frame. due to the tilt of the van (rear is slightly higher than front) and slight tilt of driveway, water sits in one of the valleys created by the roof ribs, right up against the frame of the fan. i noticed a drip yesterday during a rain storm.<br><br>so i went up and inspected everything and found where my buddy simply missed a spot which was compounded by the standing water.<br><br>it took almost two years to develop a drip. and where i live was slammed by Sandy (during which i had no water intrusion).<br><br>the fix was easy, i simply added some to the spot he missed and built it out a little bit in a way that would allow the water to run off. <br><br>the rest of the material that was used two years ago is still in perfect shape and still pliable. it is amazing stuff and i swear by it.<br><br>one caveat, it is incredibly hard to get off of your hands and clothing. use gloves. and wipe down your tools because it just gets everywhere. a small spot of the stuff where you dont want it will spread itself all over. it comes easily off of metal when its still wet though.<br><br>my installation also includes a maxxair 2 rain cover. i can have the vent open and the fan running in any weather. its incredible, even during Sandy i had it open.<br><br>tomorrow i will take photos. i did not want to touch the camera with that stuff all over my hands.