Couple of options I have seen

Couple of options I have seen in the past:

Build the "back side" of the building along the facia edge. Detail it to your hearts content & the eyes will adjust to the scene.

Build up the facia to become the back side of the building. Again, the eyes will adjust to the scene.

Keep the back side of the building open to the viewer and detail the inside.

These options will all look good in the end.

Fragile Edges

Hi Rwsnyder5,

It's amazing how much damage occurs from the casual visitor brushing past the edge of your layout.

As long as your visitors pay close attention and the building/scenery is not located at a "pinch point" of the aisle...detail away.

If you have lots of visitors, save your beautiful details for 6" from the edge of the layout and extend the fascia to become the back wall of the building.  It will save you a lot of repair work.

Brace it up strong

If you do extend the fascia up to form the back of the building don’t skimp on the bracing of the fascia, make it overly strong and brace it down to the bench work. I had one like this and it got knocked all the time, when I braced the fascia I never had any more issues 

Use a plexiglass back wall to protect interior details.

If you want to show the interior details of the structure, use a plexiglass or acrylic back wall to show interior details.  Fullerton Plaza Railway Society built a module often used in our modular club set ups that has a model of the Fullerton Santa Fe station with the tracks in front and a model of a citrus packing house on the layout edge with a period black & white photo of the interior with people packing orange crates.  The fact that the photo is black & white is not even noticeable.  In this case we use acrylic on all of our modules to keep hands off the models, but for a home layout an acrylic or plexi wall would do the same thing. 

Fascia or wall?

  If the building would have enough front to rear depth to actually look like a viable building I'd just finish the front wall in a spartan manner( no fragile details to snag on for example) . If it would just be a thin sliver of building between the track and the aisle I'd extend the fascia up to represent the cut off between aisle and modeled area.( think of it as a section line cutting thru a drawing) I wouldn't detail the interior as I'm too lazy for that but if someone detailed it for me I like the plexiglass idea. ....DaveB

Fascia considerations

I like the idea of using all the surface the area to allow more structures with the possibility of interior detailing on the "back side." But, in my experience, anything on the edge gets banged up, mostly by me!  I have trees, fencing, poles close to the edge and my structures are 2" in or more.  My layout is a pretty average 40-46"" high and this is still is a reality for me me when working on the layout than running the trains. I have average clumbiness (my wife says otherwise!).