Making Ridged Metal Roofing
Donald Nute

In an earlier article, I described how to make corrugated metal roofing for garden railroad buildings. In this article, I will describe how to make another kind of metal roofing. A ridged metal roof is made up of sheets of metal with ridges separated by a foot of so of flat metal. The ridge at the edge of one sheet is lapped over the ridge of the sheet next to it and the two ridges are crimped together to join the sheets. I first saw directions for making ridged metal roofing on Lawrence "Yogi" Wallace's website, This is also where I first saw directions for making corrugated metal roofing. Yogi also has sections on using corrugated plastic (the kind used for election signs) and the kind of styrofoam sheets used for building installations for garden railway construction. I highly recommend his site. Yogi has offered non-stop demonstrations of his building techniques at recent SELSTS meetings in Perry, Georgia. If he is at SELSTS 2009 next May and you have a chance to go, definitely find his table and ask him to show you how he uses common materials in the garden railroad.

I will go through the process of making and installing ridged metal roofing in perhaps a bit more detail than you will find on Yogi's site. But the technique is basically the same. This techniques is a bit harder and requires more time than the corrugated roofing technique, but it's nice to have a variety of roofs on your buildings.

You need a supply of soft metal sheets. I obtained some sheets from Yogi that he picked up somewhere. You could also use flattened coke cans that have been baked to soften them or metal cut from aluminum steam trays that you see at Kroger and other places. The pieces I use here are a bit thicker than aluminum steam trays. The thinner metal in trays would be easier to tear as you form the ridges in the metal. You will want to cut your sheets to a uniform size. For this project, I used sheets about 6" by 10". These were just right to run from top to bottom of the roof I was covering with a bit of overhang. A stack of sheets is visible in the upper left hand corner of Photo 3.

First, you will need to make a jig. Use a hard wood for this. I used a piece of oak that I had left over from some other project. Set your table saw so it cuts a groove about 3/16" deep. Cut a groove about 1" from the edge of your board. Then move your rip guide 1/8" inch and cut another groove. Now make another groove the same way 1-1/4" inch from the first. You can see the result in Photo 1. You will also need a tool to crimp the ridges on your roofing. Photo 2 shows the tool I bought at Lowe's. This tool was made by Wiss and cost between $25 and $30.

To make a roofing panel, start with a ridge close to one edge of a metal sheet. Extend the sheet about 1/8" past the first groove in your jig. Use a hard wood spline to make a slight crease in the metal from top to bottom. Then press harder to force the metal all the way into the groove (Photo 3) being careful not to break through the metal. I used a rather small spline and didn't wear gloves on this project. The result was blisters on my thumb and index finger. I recommend using gloves and a larger spline that is more comfortable to handle.

After the first ridge is made, turn the metal panel over and put the ridge in the second groove. Now make another ridge using the groove closest to the edge of the jig. When that ridge is finished, move the panel over and make another groove. Continue until you have made all the grooves for the panel. In Photo 4, I have moved across the panel and I am making the final ridge.

Next, place the panel on a flat surface with the ridges up and crimp all but the first ridge (the one right at the edge of the panel) using the crimping tool. (Photo 5) You can also flatten the panel as you do this by pressing with the crimping tool. You don't want to crimp the first ridge yet. It will go over the last ridge on another panel when you put the panels on your building.

I bought a nice two-story building from Michael's Woodworking at SELSTS 2007. This building came with a cedar roof that had been planed to look like corrugated roofing, but the roof had cracked. Since the rest of the building was in good shape, I decided to cover the wooden roof with metal. I cut off the corrugations with a sharp chisel to make a flat surface for gluing. In the photo, I have already applied several panels. I used Liquid Nails (the type marked for exterior use) for this project. I have found this to be easier to work with than silicone sealer or other adhesives I have used in similar applications, and it seems to hold up well outdoors. I apply a good bead around the edges of the area where the new panel will go. Put glue on the edge of the last panel you installed, but don't put glue on the last ridge. Put some extra lines of glue in the middle of the area where the new panel will go. Then put on the new panel, placing the open edge ridge over the last ridge of the previous panel. Use the crimping tool to tighten the first ridge of the new panel onto the last ridge of the previous panel. I demonstrate this in Photo 6. In the photo, I have not applied any glue and I do not have the new panel all the way to the top of the roof to make it easier to see what I am doing. Notice that I also clamped down the last panel while the glue set up.

Finally, cut some strips of metal and fold them length-wise to form pieces for a ridge cap for your roof. Glue them to your panels so they overlap. Photo 7 shows two buildings on the Lake Town & Shire. The one on the right is the building from Michael's Woodworking with the new metal roof. The ridge cap is not quite even along the bottom and I will trim it a bit. The roof appears much shinier in the picture than it does to the eye, but it definitely is a bright, shiny roof. You can overspray the metal lightly with a grey primer to take off some of the shine if you want. Hold the spray can far enough away that the paint just drifts onto the roof. It should be practically dry when it hits the roof. Follow this by an even lighter application of flat black to give some texture to the roof.

Photo 7 also shows a scratch-built warehouse with a different kind of ridged metal roof. This roof is made from commercial styrene sheets and then painted green. It looks good and I like the variation in roofing materials. I have found, though, that the styrene roofing material is quite thin and tends to become brittle in the sun even when painted. I have no doubt the real metal roof on the two-story building will last much longer.

Waht is often most visible when you look at garden railroad structures, especially those at ground level, are the roofs. That is not what your eye is drawn to: you will be looking for the details and figures. But if the roof does not look good, you will notice. You will also notice if all the roofs look alike. I have described here another method for making a good-looking roof that will add variation to you structures. And remember that you don't have to scratch-build the entire structure to do the roof. If you have several plastic kit buildings with identical roofs, consider putting your own roofs on one of two of them to add some variety.

Photo 1: The ridged roof-making jig.

Photo 2: The crimping tool.

Photo 3: Make the first ridge.

Photo 4: Use a wooden spline to make ridges.

Photo 5: Crimp all but the first ridge.

Photo 6: Crimp the first ridge of the next panel to the last ridge of the last panel.

Photo 7: A warehouse with commercial styrene ridged roofing and another building with real aluminum ridged roofing.

A roof cap made up of V-shaped strips of metal has been added to the building on the right.