Creating a new Wall Default

[BB boy]

Creating a new Wall Default
You probably don't need to make a "new" wall default. If I understand what you want to do, you have a wall that returns onto the porch.
Part of it is brick, and part siding. You need to use the wall break tool. On the tool bar>Wall Tools>then Break Wall.
You have to place a break point at each location where the wall type changes. Then using the Select Objects arrow, select each wall between the break points, select and open that wall, then the wall dbx, and then you can change the materials to what you want. You will also need to align the walls as the different materials will give you a different wall thickness. Assuming your wall would line up on the inside (no offsets). Hope the attached explains better.
Hope this helps
BB