What is the best way to make industrial concrete flooring?

I would use .060" styrene sheet. You can paint or sand it to the texture and color that you want.

Alan Graziano

I'm not saying it's the best way, but this is Plaster of Paris.

Closest probably to reality and looks good, too!

In-place: plaster will work well. Hydrocal, plaster of Paris, or even joint compound will work, though joint compound can be a little soft.

Portable: 1/4" masonite, scored a little deep for expansion joints, roughed up a bit with sand paper, then primered and painted with concrete textured paint.

This base to a Korber 304 (4) stall house is luan board that has been skim coated with drywall compound and let dry, then sanded and a second and third coat added. I also used a Sherwin Williams spray can, sand-able primer/sealer (PrepRite, ProBlock white 141-1669).   Smooth surface was then painted with either Krylon Camouflage 4291 Khaki or Rusto-oleum Camouflage 1917 Khaki. Yellow-ish look for aged concrete. New concrete a lime grey. IMO.  Both cans were on the shelf.  Application of an india ink wash to tone it down needs to be done.  

Assembled 304 house.

Excellent Mike CT.

I used anchor cement from Lowe's.  Mix with water to a pancake consistency, poured into formers using 1/4 inch basswood strips and smoothed with wet sponge.  Waited about 30 minutes and used a the end of a wood drill bit to scribe expansion joints and cracks.  When it dried it looked, well, like cement or concrete.  Paid $8 and covered about a 3'x3' area and had some left over.  Sets hard in about one hour and fully cures within 3 hours.  

By the way, if you need to move it or change the shape of your "pour" and you made the expansion joints deep enough, you can often "pop" the sections out and remove or expand. 

Got the idea from an article in Model Railroad Craftsman from a modeler who paved all of his roads with thin pours using masking tape and a joint compound (drywall) applicator.  I have photos of some of the area but cannot access them now.  Will share the pics if you desire

Vulcan's plaster of paris floors look about perfect so there are many ways to skin this cat.  Best of luck.

My favorate for roads, and oncrete pavement is Durhams Water Putty. It scribes well just before it set up, takes paint and stain well. I have been using this product for about 20 years. Its also very durable.

Les Lewis,  www.westportmodelworks.com

Considering that its inside the building, you may want to try foam board painted with flat primer grey. You can first cut the sections to fit your interior and tracks, then a quick spray and you are done.

You could also give them an India ink wash to add some variation and depth.

Rod

I agree with Rod Stewart. Get yourself some tan "GatorBoard" from Micro-Mark and paint it with either concrete or aged concrete paint that they offer also. You can get the paint in either water or oil base. I use the water base because of easy clean-up. I've used the Gator-Board for a slab of concrete for my sub-station and it looks very realistic. It is 3/16" thick or 3/4' scale. I've used the board for many other applications and have been very pleased with it. In fact, I am in the process of building a depot using the board for the structure.

Gator foam is extremely easy to use.

Cut it with a knife edge jig saw blade and spray with gray primer.

Read my OGR article on asphalt roadways. Instead of charcoal or dark gray, you would use lighter gray and weather it according to preference. Foam core can be used also, but it will warp unless carefully prepped with primer. Gator foam will not warp.

I also use Durham's water putty for certain applications. For a flat concrete floor under an engine house, it would require much more work than gator foam. I could have a Gator foam concrete floor finished in half an hour.

You have received lots of expert advice from the above fellows. I know that each technique works. I prefer the techniques that result in a great looking finish with the least work and aggravation.

Scrappy

I've also used a flooring skim-coat material to blend grades, easily, it could be used for concrete.



Allows you to work from rough grade to a finished slope.

As others have said I use either foam board or hardboard (smooth both sides). When I use foam board it is only for my layout since it is very light and easily 'crushed'. I tend towards sidewalks only. I use hardboard for all customer work and building floors because of its stability and durability. Either way the paint scheme is the same except for the last coat depending on whether a light or dark dirty concrete effect is desired.

Some examples are shown below.

The material is less important than the finish. I've use MDF, plastic, and just painted over plywood, though depending on the grain of the plywood you can apply a coat of drywall compound to smooth it out. I use a two color method that I learned about from Norm Charbonneau.

First color is a tan similar to older desktop computer color. Then a wash of very dilute black latex (~20:1 with water). Depending on how weathered you want it either wipe on wipe off very quickly or airbush the mix. 

Below sidewalk is MDF, street is plywood.

Pete