Train Room Suggestion

Well, I'd consider a lot of lighting above the layout.  I thought my hi-hats would be enough, but I am in need of more lighting. Many folks do track lighting, and I'm considering adding that to mine.

I'd arrange for air exchange if you're a smoke fan. This is another issue I have here, I'm thinking of an electrostatic air cleaner.  Right now I have to limit the smoke when the visibility drops to less than a layout width.

As for windows, think about what the layout will look like.  If you're planning an around the room on the walls, that will surely affect window placement.  If you're looking to be able to walk around outside the layout on all sides, then windows can be wherever you like.

Although there is a lot of discussion about multiple power circuits etc. you can run a pretty good sized layout on a single 15 or 20 amp circuit.  For completeness, I'd probably have two circuits on the same side of the panel so they're in phase for any future expansion.   Unless you are contemplating some really power hungry stuff, 30-40 amps of 115V capacity should be more than sufficient.  Also, make sure the outlets are inside the building envelope for the layout so you don't have the issue of getting power in across the floor.

You mention single story, I'd make the attic of this addition accessible for storage, don't miss the chance to have extra storage!

I would consider building a "pop under" into the floor.  If code compliance is an issue, this may require some creativity.

By me, a 20x25' foot concrete block addition would have a garage door!  I don't know your situation, but it may be an option to have a large door that opens (even to the side or back) to create a shop or indoor/outdoor living area that adds as much value and versatility as possible to the house.

I would concur with all that was said above but would consider outlets about every 8 feet along each wall, you never know where or when you will need power and the chances of all of them being used at one time is pretty slim. I would also consider maybe French Doors they will be much more energy efficient than a garage door but still be wide enough to get lumber in and out during layout construction. I used 6 inch LED Flush mount lamps 5000 lumins but a big consideration is what kind of ceiling will you have drywall or dropped ceiling as that may limit your lighting style. My basement is 36 x 56 and I have about 40 of those LED lights and wish I had more lighting in some areas. Also consider when you are working on the layout you may be casting a shadow over an area so consider light spacing to help limit shadows. Good Luck and enjoy.

Another lighting tip ...

After construction of benchwork and installation of the platforms, you'll be working UNDERNEATH to install wiring for the tracks, switches, action accessories, street lights, and such. Consider under-the-platform lights so you're not scooting along on a mechanic's creeper "in the dark."  Kitchen under-counter light fixtures could be used; each one with its own on/off switch so you can reach up and turn them ON and OFF as you move from place to place.

Just saying ...

Mike M.    LCCA 12394

In case you already have a layout, those small battery LED “puck” lights can be lifesavers for spots underneath where there’s no convenient wiring.

Also, recent bunged-up leg has made me much more aware of the value of grab irons and reinforced edges on frequently grabbed or leaned-on items. If you can plan for a little extra edge in the spot where you routinely swing underneath, you can hide the grab iron and still pull yourself up or out with it, lessening the chance that you’ll grab for the edge and either derail something or derail yourself.

@SantaFeBob posted:

I'm looking into putting an one story addition onto the house.  It will be concrete block construction.  About a 20 by 25 foot room.     Looking for any suggestions on lighting, electrical outlets, air filtration, window placement etc... I should consider for this room?

Hire a good architect.

You are adding a room to your house, think real estate value. Someday your house will be sold and if you have some special, customized room it may not help. Building codes will dictate adequate placement of outlets and to some extent what you can do with doors and windows. Lighting may be the only part of a layout that needs some specialized treatment and there are ways to do this to make these changes reversible.

That's my $.02 worth.

@Mike H Mottler posted:

After construction of benchwork and installation of the platforms, you'll be working UNDERNEATH to install wiring for the tracks, switches, action accessories, street lights, and such. Consider under-the-platform lights so you're not scooting along on a mechanic's creeper "in the dark."  Kitchen under-counter light fixtures could be used; each one with its own on/off switch so you can reach up and turn them ON and OFF as you move from place to place.

I did that and went one step farther, I have an RF remote control relay module to turn them on/off so I don't have to go to the switch location.

I used these from Amazon: LED Under Counter Lights.  I just dispensed with the little touch switch and used my RF module.  I have a keyfob, (or two if I decide I need one in another place on the layout), to turn them on/off.  I have a total of ten of the lights around under the layout.

Couple of quick suggestions:

Attic storage as GRJ mentioned is valuable for whatever.   If the new attic is isolated from main home attic pull down steps need to work with the track plan/bench work.

In addition to code compliant wall outlets consider fascia outlets.  Consider under floor conduits for floor outlets in center of room.

You WILL become older and less able.   Consider to never use a duck under or pop  up access.  Plan to never have to climb up on the platform.

HVAC duct placement to compliment bench work.

Many fluorescent lights will be phased out over the next year so choose lighting with a future. <<<<<

Consider sound and smoke control for those in immediate adjacent rooms.  You will want to do run what you want the way you want without need of domestic compliance.  Solid core door with a floor sweep or threshold.

Dedicated HVAC system in attic.

Comfortable floor covering.  Carpet tiles for ease of spot replacement due to solder, paint, plaster, etc, etc.

Sprayed in insulation will provide excellent ceiling insulation.

Soft surfaces for sound control.  Three rail can get real loud real quick in a small room with four flat walls.

If your floor size is due to code restriction of square foot limitations consider chamfered corners which will allow for longer over all room.

A series of skylights will provide an abundant amount of illumination on many days.

Consider an external staging yard:

@Tom Tee posted:

Dedicated HVAC system in attic.Consider an external staging yard:

I'd consider the ductless mini-split unit, works very well for us here.  Doesn't take up any attic space.  For a single room, it should work well.

@SantaFeBob From your profile, I see you're in Florida.  If you plan to have an attic and you want to store items in it which could be damaged by excessive heat, maybe consider insulating the attic to include it within the conditioned part of the building's thermal envelope.  This is becoming more commonplace today especially, as previously suggested, having closed cell spray foam installed by a reputable contractor.