I installed a woodstove in my shop, the walls are all cement block, so I went up 2', an elbow, thru the wall, another elbow, and then 20' up the wall to the roof. The outside elbow is constantly dripping water, of course, none of these pipes are insulated, since it's installed against block. Is there any way to stop the condensation, the cap is a little shanty style cap, maybe I need a better cap?