Using C-Channels to Construct a Steel and Cedar Fence
April 8th, 2021 | Back to Blog Listing

Introduction

This is a new method that I came up with for building a Steel and Cedar fence using stainless steel C-Channels in place of other methods like angle iron.


A section of the fence shortly after completion

One of the difficulties of building a steel and cedar fence is the process of physically adhering the cedar pickets to the steel itself. While this might not be immediately obvious at first, the mechanics behind it actually create quite a lot of work for anybody building this type of fence.

The typical method used is to weld angle iron pieces to the vertical posts. They are positioned on the inner tracts of each section and allow various types of backing boards to be screwed onto them. These backing boards can then be used to affix the cedar planks.

I came up with a new method for accomplishing this same process by using Stainless Steel C-Channels. The channels allow for standard pressure treated 1x4s to be slid into the channel slots. These are then used to affix the cedar just as in the standard method.

Here's a detailed video of how I made this work. Full textual instructions can be found below that.

Acquiring C-Channels

Once I came up with a proof of concept for the work, the first challenge was just acquiring all of the C-Channels. I found what I needed at Home Depot, but I thought surely my local metal distributor would have these at a better price and quite possibly in longer segments.

It turns out that I was mistaken.

My local steel company sold C-Channels too, but unfortunately they were quite different from what I actually needed. If you look at the two of them side-by-side, you can see that one of them has angled edges. The reason for this is how they manufacturer them.


Two different types of C-Channels, one with straight walls that I found at Home Depot and one with angled walls that I found at my usual metal distributor

The C-Channel on the right (which I'm told is called "pig iron") is actually manufactured in the forge. They start with a solid brick of steel and then use a press to carve out the channel. The problem is that excess steel has to go somewhere and so it's left behind in the channel. That's what forms the angled grooves.


Some of the C-Channels I acquired at Home Depot just before cutting them

By contrast, the C-Channel on the left is made from an existing piece of flattened stainless steel. They use a machine to bend the two sides of it. This creates the channel with the straight walls. This is an important distinction for the method that I came up with and these types of C-Channels are required for the process to work properly.

Once I had all of the C-Channels that I needed, I laid out half of them on a ladder next to me and started on the process of preparing them.



Jig to Cut the C-Channels

Given that Home Depot only sells the stainless steel C-Channels in 36” pieces, I needed make literally hundreds of cuts for the 3-1/2" pieces that would be useful on the fence. To ensure they were done with relative precision, I built a simple jig out of some scrap wood.

The jig was designed so that the C-Channel could be slid into a groove with walls on either side locking it firmly into place. The outermost edge had a wall that would stop it from being inserted any farther into the jig. In order to get the proper cut, the C-Channel had to abut this outer wall. I left a several inch wide gap in the two side walls. The 3-1/2" cutline that I needed was where the gap first started. So in other words, so long as I cut the C-Channel as close to that edge as possible, the resulting piece would be sufficient for what I needed (with a precision of maybe +/- ¼").


The jig I built for cutting the 36" C-Channels into 3-1/2" pieces

It took about three hours for me to cut all of the pieces that I needed. It should be noted that safety equipment is of the utmost importance here. In addition to always needing safety gear when working with a grinder and cutting steel, the sheer volume of the material being cut produced an unbelievable amount of metal dust and shavings. For that reason alone, I would strongly advise wearing a breather as well as an apron.

Metal dust and shavings are incredibly difficult to get out your clothing. What's worse is that because so many of our modern conveniences rely on strong magnets (your phone, for example), the tiny shards of metal will get stuck to everything and are very difficult to remove.


A view of the jig I used after cutting hundreds of C-Channels


Some of the metal dust that resulted from the massive amounts of cuts made


The Homer work bucket filled with 3-1/2" C-Channel pieces

After each cut, I'd just toss the 3-1/2" C-Channel into a Homer work bucket. The bucket eventually became extremely heavy, but not so much that I couldn't move it around. It provided an easy way to move them to each fence section as we worked on welding them into place.



Welding the C-Channels

Welding the C-Channels into place wasn't especially difficult, but it did require some reasonable welding skills. Admittedly, they don't require a lot of welding to secure them to the frames, but rather can be adhered with just a few well-positioned tacks. We found that placing a tack on the underbelly of each C-Channel as well two tacks on the outer portion of each one worked just fine.


One of the C-Channels tacked into place. The board in this photo is a standard 1x4 untreated common board. This was used as a test, but only pressure-treated wood was used for the final product

Assuming each fence section is 8 feet wide, you should plan on having 3 pairs of C-Channels per fence section. One pair on each of the outermost parts of the section and then one pair dead center.

If you have any sections of fence that exceed 8 feet in width, you might consider using 4 pairs of C-Channels for such a section. In that case, use two pairs on the outermost posts of the section and then space two more pairs equally within the section itself. Keep in mind that if you do this, you’ll want to divide the width of the fence section by THREE and not by four. The reason is because you need to use the number of gaps required (3) for the math and not the number of channel pairings (4).



Once you have all of the C-Channels welded into place, you'll want to paint them. For a black fence, I'd recommend using Rustoleum Black Gloss paint. You can use a brush if you prefer, but I found the spray was much easier for painting the C-Channels given their irregular shape and how small they are. Still though, this is entirely a preference.

At this point you'll be ready to start attaching the 1x4 backing boards. These should be pressure treated boards and you'll want to make sure that you spend time carefully choosing the boards to ensure minimal warping. Horizontal warping is especially problematic with this method given the boards will need to be properly fit between each pair of channels. You'll want them to be as straight as possible.


Pallet of pressure-treated "Yellawood" 1x4s at Home Depot

I found that cutting all of the backing boards was probably the most labor intensive part of the entire job. Because of the unusual shape of the C-Channels, it can be difficult to properly measure the height that you need. Ideally you would run the tape measure from the floor of the lower C-Channel to the ceiling of the upper C-Channel. However, given that each C-Channel is just ?" thick, you can simply measure the distance between the two horizontal steel tubes and then subtract ¼" from the total required height. This is what I found easiest.

I also tended to err on the longer side of my measurements as I needed to ensure that each backing board was snugly fit into place. Consequently, I would measure the distance needed and then subtract just under ¼" from the measurement before making the cut. This would usually result in the board being slightly too long to fit inside of the C-Channel pairing. I would simply set the bottom part of the 1x4 in the lower channel and then see how close it was to fitting inside of the upper channel. Once I could see how much was left to cut, I could usually eyeball it from there and make very small adjustments. While this took a lot of additional time, I wanted to ensure I got the height of the 1x4 as perfectly fit as I could. This would occasionally mean I had to make 3 or 4 cuts on the same piece of wood, but I think the results speak for themselves in terms of the precision that I ended up with.


A section of the fence with three backing boards and a single cedar picket held onto the bottom.
This was still testing the proof of concept

I should also note that just because the left side of your fence section measures some height does not mean that the right side will have an equal height. While you should have certainly used a level when installing the horizontal tubing, it's very possible that there will still be a slight angle to the tube resulting in one side being slightly higher or lower than the other. While this isn't generally perceptible to the eye (provided you indeed used a level), it makes a significant difference fitting the 1x4s given the precision required to slide them into the channels.

The backing boards should fit perfectly into place between each pair of the C-Channels. While you don’t want them to be loose in any way, you also shouldn’t require a great deal of force to knock them into place. I found that they worked best when they required a gently tapping from my hand or a mallet.

But that's basically it. Once all of the backing boards are in place, you can proceed with installing the cedar pickets as you normally would. Cut them to width and then screw them into the backing boards.


Various sections of the fence with the backing boards exposed



Attach the Cedar Pickets

Assuming that you're using 1x6 cedar pickets and paired with the 1x4s, this means that the total amount of usable wood depth should be 1-½". I used Spax #8 1-¼" decking screws for the job. This ensured that none of them would penetrate the 1-½" of depth. The brand is generally very well-received for these kinds of jobs.


The boxes of Spax screws required to affix all of the cedar pickets

If you have any questions about how to apply this method, please feel free to contact me!


Working on cutting and affixing the cedar pickets to one side of the fence


Me, after getting the first few sections of fencing finished after weeks of hard work