I used Kool Seal White Elastomeric Roof Coating to cover weather exposed CDX Paneling. Now CDX in itself is an exterior panel material, but NOT if it is directly exposed to the elements, (rain, snow, ice, sun, humidity, etc., etc.). My project is an 8 x 8 "lean to" for my lawn tractor. I applied Kool Seal to one surface and the all the ends. The CDX really sucked up the sealant. I only bought (1) gallon, so I was only able to apply (3) coats. Very easy application with a roller for my project. The consistency was twice as thick as a good regular exterior paint, and cost less. I applied Kool Seal several days ago and it has rained several times since. I would say at this point My CDX panel is NOT going to make it. Moisture is still seeping into the ends of the paneling even with several coats of Kool Seal. I can see the CDX panel beginning to swell. With that being said, I still think that Kool Seal is a good product if used for the correct applications listed on the can.