Back to front.

I am building a multi-deck N scale layout. I put up the hardboard back board first, then my lady painted the backdrop and I added my 3D background.

Next I built all the benchwork and laid most of my track on both levels.

Right now I have the basic landforms in and terraformed (basic contours established).

I will be building my scenes on my benchwork on hardboard and dropping them into the layout when complete. Even my largest village (20" x 72").

Once placed on the layout, the dioramas will be worked in.

When doing them, I will complete the upper level first and use drop sheets on the lower level to avoid damage from dripping scenery.

Both Ways Possible

On my last triple deck layout I built from the bottom up.  That was nice because I never had to worry about bumping my head on things above.  The bad part was the main deck was the widest, and kind of got in the way as work progressed above it. 

On the current layout I'm building I installed the joists for all four decks, beginning with the lowest deck first.  I had to do it that way to determine the proper height for each deck.  When I get ready to start laying track though, I'm going to work from the top down this time as that will make things much easier, and hopefully will move construction along much quicker. 

Bottom up...

I built from the bottom up, and I used the lower levels to support the upper.  Trackwork is a lot easier without a deck over it. 

Randy

Top-bottom

I have built my shadow box sections bottom up.  Restricted clearances makes track installation and things like static grass hard to apply with the level installed above.  Down side is construction on the upper layer tends to rain dust and sawdust down onto the lower level.

Top Down

Top down for me - all of the upper valances and lighting were done first. This would have been very difficult later in the process.
 
 

Mushroom - bottom up

Top or bottom?

  If you build your benchwork to suit you can work on top ,bottom, or both anytime. Where to start is a minor matter as all the stuff is going to be there in all it's glory for a long time so might as well get used to working on the different layers from the get go. Of course the simple way to avoid the top/bottom choce is to just build one level layouts:> )  ....DaveB

Depends

i actually thought about this when I was building bench work and track.  I built bench work and track bottom up.  But , I got in a hurry to complete the main line and skipped some sidings and spurs.  That was a mistake.  It is hard to fill in the extra track under the upper deck.  

My good friend and neighbor also did some scenery  on the lower deck first.  Not such a good idea.  The upper scenery will make a mess of the lower scenery, drips and such.

This is the way my situation worked out.

Roger in La Luz, New Mexico

...

Start to Teardown.  That is the order of all layouts.

Both

I built the bench work and laid the track from the bottom up, and now am building the scenery from the top down.  That way I can use large drop cloths to cover the lower level(s) while working on the scenery.  I did install and paint all the backdrop after the benchwork for all levels was reasonably complete.

thanks

Thanks, that confirms my plans to build bottom-up - but without completing scenery. I was also going to skip some sidings in order to get the mainline done and put off until later figuring out the configuration of industry buildings, but I'll have another think about the wisdom of that. The thing is I don't have any pre-built buildings so I don't know how much space to allow.

My decks aren't going to be too deep in most places. There are some corners where the bench work will extend into the corner and the corner wont be used for anything (maybe a mountain, or maybe just hidden behind a coved backdrop). But I expect all the track to be within 18" of the aisle and any additional depth to be rising ground to support my Appalachian Mountains theme.

+1 for masking tape scenery contours