Prevent Exterior and Interior Walls from Joining

[MAAMECH]

So as you can see in the attached file I have a building with an exterior set of walls and then rooms outlined by interior partition walls. I'm having trouble around the edges of the rooms where an interior wall runs right next to the exterior ones. I want them to stay separate so you it will look like it does in the attached drawing. I've tried changing the function type of the wall assembly. The only way I've found to keep them apart is to right click the grips and disallow joining. But that prevents the interior set from joining together so I wind up with a strange final product. To sum up, I want the exterior walls to join with the exterior walls and the interior walls to join with the interior walls but no joining between the two, any ideas?

[freestuffmahn]

You can do it by changing wall's materials proprety, here is how you can do it:

1 - Set detail level to Medium or fine

2 -Edit type> Structure>Edit>

3 -

 you can choose any color you want.

[L.Maas]

I would probably use two separate wall types. One for the outer and second one for the inner (see screenshot).

You can draw the inner wall against the outer wall (without overlap). For the situations were the inner wall is perpendicular to the outer wall you can choose to disallow join.

If you have an inner and outer wall running parallel and you have an window or door. You can place them in the outer wall. You would then have to create an opening in the inner wall.

In the screenshot I have used two solutions for the windows in th eupper part I have the inner wall turn back into the outer wall (using disallow join). In the door and window on the right I placed an opening in the inner wall at the location of the window and door.

The solution you choose is what is most suitable to you. Try to think how they would construct this on site.

As you can see from the sccreenshot I do not think you would have problems with joining walls. They can be (un)joined  when necessary.