Real scale cedar shakes make a great-looking roof for both large and small buildings in the garden railroad. You can buy cedar shakes at many hobby stores that carry doll house supplies, but they are a bit on the expensive side. For the price of enough shakes to roof one medium-sized building, you can build a chopper that will allow you to make all the cedar shakes you want quickly and easily.
The first photo on the right shows my chopper. I recommend using a hard wood for the chopper. The one shown here is made mostly from some oak I had left over from another project. You can buy 4" wide oak boards at Lowe's or Home Depot that work well for this project. You need to cut four pieces: a long cross piece, two supports to rest on your legs or a table, and a piece about an inch wide to support the blade. Dimensions are not critical. Screw the two supports into the long cross piece from the bottom using #6 1-1/4" wood screws. Countersink the screws so they won't stick out and mar your work table or snag your clothes. The base pieces should extend beyond the back of the cross piece by the width of one of your boards to provide support for the blade support. Drill a hole in the blade support large enough for a 1/4" bolt. The hole should be near one end of the support. Cut the blade support so that when you rest it on the base piece, the hole is about 1-1/4" above the cross piece. The blade is attached to the back of the long cross piece with a couple more #6 1-1/4" wood screws.
The hardest part of the project is preparing the knife, but that isn't as hard as it probably will sound at first. You will need a source of heat that will turn the metal of your blade red. I used a cheap butane torch. I bought the knife for my chopper at Krogers. Notice it has a wide blade with a high, comfortable handle. This works well and is comfortable to use. Heat the blade and use some sort of punch (a nail will do) to make a dent at the spot where you will drill the hole. Reheat the blade if necessary until it is red hot, and then drill a hole big enough for a 1/4" bolt. Heating the blade makes it less brittle so it doesn't break during the drilling. Just heat the end where you will drill. This doesn't seem to affect the sharpness or hardness of the back part of the blade where the chopping is actually done. It's also a good idea to grind off the point of the blade to prevent accidental cuts. I used a dremel for this.
Attach the blade to its support with a 1/4" bolt, some washers, and a couple of nuts. Two nuts tighten against each other and don't come loose as easily as a single nut. Cut a long guide from some scrap wood and screw it to the top of the chopper. You want this at right angles to the blade and close enough to the front so that a 3/4" piece of wood fits between it and the front of the chopper. Attach a small L-bracket to the chopper flush against the blade. This keeps the blade from wobbling when you chop shakes. You may need to bend the bracket a bit to get it straight up and down. You can also attach a stop to your chopper so each shake is the same size if you want. You can see some screw holes next to the L-bracket on my chopper where I tried this. I decided I didn't like the stop. It was hard to position exactly and I found I could do as well positioning the wood to be chopped by eye. Also, when you have a stop you have to remove each shake as you chop it. Without a stop, you can just keep pushing the shakes to the right as you chop them.
You make a blank by cross-cutting a 1-1/4" wide strip from the end of a nominal 1" cedar board. This will give you a "stick" of cedar with a 3/4" x 1/1/4" cross-section. Put the blank against the guide on the chopper, narrow side on the base, with about 1/8" extending past the blade. Then chop a shake cutting with the grain of the wood. Be sure to keep the blade against the L-bracket so you go straight up and down with your knife. With a little practice, you will find you can chop hundreds of shakes in a short time. Don't worry about shakes that don't come out right. Just throw them away.
I attach cedar shakes to the roof of a building with Liquid Nails - the kind that says it is for exterior use. I mark a line about 1" from the bottom of the roof and put down two beads of glue, one at the edge and the other just below the line I drew. Then I take a shake and put one end of it in the upper glue bead. I put the shake flat against the roof and scoot it up until it is flush against the line. When one row is done, I draw another line and put a bead of glue just below the line and another on the edge of the last row of shakes. I overlap the shakes so the edge of the one below is in the middle of the one above. You will need to cut a few shakes in half to get the edges to come out right. Glue a double row of shakes along the top to cap the roof or cap it with long pieces of wood. I seal my roofs with a deck sealer.
Here are a couple of buildings I built from scratch and roofed with cedar
shakes I chopper. Have fun!
The assembled shake chopper.
The shake chopper with the knife removed.
A cabin with a cedar shake roof
The Lake Town Depot on the Lake Town & Shire is roofed with cedar shakes I chopped myself.