Had a deck on my house when I bought it. 10x12. Too small so I doubled it. Original had the pressure treated 2x2s for balusters so I did the same on the addition.I'm in the mood to change and I like these black aluminum rectangular ones that screw directly to the rail. But, they all say you can't have direct contact with the new kind of PT lumber or it will corrode. They supply washers to put between the rail and the aluminum. With over 100 to screw on at 4 screws per, that will be pretty annoying. If I skip the washers, what kind of carnage are we talking about? If it's really important for them not to touch the PT lumber, how about if I just replace the rails with regular 2x4s? As long as they have a good stain and since they are under the rail caps they should last 20 yrs shouldn't they?