How to Run Ethernet Through a Wall Horizontally

I noticed this morning that most of the guides that talk about running Ethernet cable through walls recommend that you do so by following the tried and true method of first running the cable up or down the wall vertically and then getting the cable where it needs to go by utilizing a space like an attic, basement, or crawl space. While I agree that is often the best way to go, there are some situations where choosing to run Ethernet through a wall horizontally is the better choice.

You may need to run your network cable through a wall horizontally because there is no usable utility space above or below the room you are working in. You may also choose to use one of the methods in this article because the distance that your cable needs to travel is not very far and it does not make sense to run the cable to the attic and back again just to extend a network across a room. Whatever the reason you may need to run an Ethernet cable through a wall horizontally, here are a few of my favorite methods for getting the job done. 

Running Ethernet Through a Wall Horizontally in New Construction

Just like most physical networking tasks, this job is most easily accomplished when working in new construction. If you have the opportunity, the best time to install any kind of Ethernet cable, including cat 5e and cat 6, is after the wall studs are framed up but before the sheetrock is installed. 

If you are lucky enough to have the opportunity to work on your installation at this point in the construction process of the home, running Ethernet through the wall horizontally is relatively trivial. It is nothing more than drilling a hole in each stud between your starting and ending locations, threading the cable through the holes, and preparing the cables in such a way that they do not get damaged throughout the remainder of the construction project. Once the wall is finished and painted you can come back to terminate the cable and install the faceplate. 

Before you start cutting holes in your wall studs you must take the time to understand local building codes so that you don’t accidentally cause problems for yourself down the road. Building code varies from place to place so you should take the time to make sure you are following the law where you are but here are a few rules of thumb that should keep you out of trouble most of the time. 

  • Drilling holes in wall studs will weaken them. You should not drill any holes larger than they need to be.
  • Most places forbid drilling holes that are larger than 40% of the total width of the stud. 
  • One company I used to work for only allowed us to drill holes one inch in diameter or smaller as a company policy.
  • If you are running more cables than what will fit in a properly sized hole you can add a second hole a few inches above or below your first hole without adding too much additional weakness.
  • There is a danger that a drywall screw can hit your cable when the sheetrock is being installed. To mitigate this risk keep all of the holes more than an inch from either side of the stud.

Once the holes are drilled and your cable is threaded through the wall, protect the end of the cable from damage with a gang box like the one in the picture below. You should also take the time to make sure that the cable is snug enough that it will not wrap in front of or behind a stud. If there is too much slack in the cable it can get pinched and damaged when the sheet rock is being installed. 

While having the opportunity to install your network cable inside of a wall before it is finished is the best-case scenario, there are still a handful of options if you are not so lucky. The remaining methods I will write about today are all things you can try if you need to run Ethernet through a finished wall horizontally.

Installing Ethernet Behind Existing Trim Work

One of my favorite ways to run Ethernet cable through a finished wall horizontally is by running it behind the existing trim. The reason that I like this technique is that it is very flexible, completely hidden once it is finished, and does not cost much money.

The first step to completing this technique is to carefully remove the wall trim boards that you will be running behind. You need to take your time here as it is relatively easy to damage the boards and any wall paint that may stick to the boards as they are removed. I find that taking the time to run a razor blade along the seam between the wall and the trim goes a long way in freeing up the board and avoiding damage to the paint. 

Once the trim has been removed from the wall you can start by cutting a hole in the wall where the cable will terminate. Before you cut the hole use a stud finder like the one below to make sure that you are cutting the sheetrock between two studs rather then directly over one of them. This hole should be cut to the right size to accommodate a low voltage, or mud in, ring like this one. The hole should be just large enough to fit the ring while the arms are collapsed but small enough to be completely covered up by a standard faceplate. 

Next, drill a hole through the drywall directly below this new location and behind where the wall trim will be reinstalled later. Assuming this location is within a couple of feet of the floor, it should be relatively trivial to reach down into the wall and grab onto the end of an Ethernet cable that is threaded through this new hole.

You will need to create enough space behind the trim work for the cable to fit without getting pinched when the trim is reinstalled. To do this, I like to use a utility knife to cut a v-shaped channel down the length of the run. Be careful when cutting this channel to pay attention to where the nails or staples will be installed when the wall trim is reattached. If a single nail hits the cable at any point you will need to replace it. 

Be very careful when reattaching the wall trim that the cable does not get pinched or punctured by a fastener. If needed, you can use cable staples to keep the cable in place and help this step go smoothly.

After the trim has been reattached you will likely need to go through and repaint or at very least touch up the paint on the trim. I have never seen a situation where the trim has been perfect after a job like This but if you are careful you can get it very close. 

This may seem like quite the process just to hide a cable down one or two walls but it really is one of the best methods to use if you need to run an Ethernet cable through a wall horizontally and want it to look as nice as possible when it is finished. 

Installing Additional Trim Work

One of the biggest drawbacks to installing Ethernet cable behind existing trim is the fact that said trim work is seldom the same after it has been removed and reinstalled. People who need the project to look absolutely perfect once it is finished may need to consider installing new or additional trim work.

While it is possible to run your Ethernet cable behind the existing trim and then replace it with fresh boards so that everything still looks perfect at the end of the project, being open to buying new wall trim also opens up some additional options. 

Two such options are adding a second piece of wall trim on top of the existing trim or installing crown molding at the top of the wall. Both of these options can be quite a bit faster than trying to use existing trim in some situations and can look quite nice once it is finished if you do it correctly. Just be careful which styles of wall trim you choose to stack together as this ca

n look absolutely horrible if you are careless with this decision. 

I have personally installed crown molding in multiple residential projects as a way to create pathways for network infrastructure. To me, it is a particularly attractive option because of the large void that is created behind this style of molding when it is installed. This large space is really easy to work with and provides more than enough room for any residential project I have ever worked on. In this image you can see the nice big space that is created behind a piece of crown molding.

One last thing to consider before choosing this technique is the fact that it requires you to either pay someone to install the new trim work for you or you will need to have the tools and expertise to be able to do it yourself. This can still be a problem when working with existing trim but the problem grows when you add the more technical tasks cutting and fitting new boards to the to-do list. That being said this really is the best option if you want the project to look as good as it possibly can once it is finished.

Running Ethernet Behind Finished Drywall

It is possible to run Ethernet cable behind existing drywall but it is a messy job that can be relatively expensive if you, like me, do not have the skills to repair drywall well. This technique is something that can only be used if you have a wall texture that can easily be replicated or if you do not mind if the wall does not have a perfectly uniform texture in the end. 

The process is rather simple but crude. Before the cable can be run enough drywall must be cut out for you to have the space needed to drill the holes in each stud. Once the holes are in place you can easily run the cable where it needs to go. Afterward comes the difficult part of this technique. The drywall needs to be repaired. I would strongly recommend that you do not make this your first drywall project unless you do not care what it looks like in the end. Matching drywall textures can be extremely difficult. I have a subcontractor that I use for this kind of work and even he, with his decade or more of experience, can not always make the wall look all that good depending on the wall texture he needs to match.

While this method of running Ethernet cable behind finished drywall can work I do not recommend it unless you do not have any other options or if you don’t mind if the wall doesn’t look perfect in the end. I find that using some of the other techniques in this article leads to better results in most cases. I will however cut out drywall and then pay to have it repaired when I do not have another choice. 

Running Ethernet in Surface Mount Raceway Moulding

The last way that I commonly run network cable along a wall horizontally has a unique set of advantages and disadvantages. The two major advantages of using surface mount raceway are that it is by far the fastest method here and it is the only technique that is temporary. The biggest disadvantages are the financial and aesthetic ones. Surface mount raceway can be expensive and has a distinctly industrial look to it that many people may find to be a turn-off.

This product allows you to contain Ethernet cable within a plastic molding that is applied to walls and ceiling with drywall anchors or command strip style adhesive pads. Because no real modification needs to be done to the drywall or its molding, this is a relatively fast and easy process. You need only buy the proper pieces of raceway, cut them to the proper lengths, and apply them to the surfaces where you need to run your cable. Once the molding is installed you can install your cable and snap everything closed. 

Provided you chose not to use permanent fasteners when installing the molding, removing the installation is even easier than installing it in the first place. This makes surface mount molding the ideal choice for someone who is renting or leasing the space where they are installing the cable. Provided you have the budget and don’t mind the look of the surface mount raceway it may be the best choice for you. Because of this, I use this method more than any of the others for commercial or industrial applications. For residential applications, I almost always end up reaching for one of the methods that look better in the end. 


Whether you are looking to run Ethernet through a wall horizontally because it is your only option or because it seems like an easier option than using a more traditional pathway, I hope that you were able to find a technique in this article that will be a good fit for your application. If you are looking for the quickest and easiest way to run the cable, try surface mount raceway molding. If you are more concerned with the way the end product looks, I would recommend either cutting and later repairing the drywall to install the cable behind it or hiding the cable behind traditional trim boards such as crown or wall molding.