What to Think About Before Running Cable Through Finished Walls
Running cable through finished walls is doable, but it takes planning. Here is what homeowners should think about before cutting into drywall for Ethernet, HDMI, or speaker wire.
Know Your Wall Type Before You Start
The type of wall you are working with determines everything about how a cable run will go. Standard drywall over wood studs is the easiest scenario — you can cut small openings, use flexible drill bits to bore through studs, and fish cable through the cavity with minimal difficulty. This is what most homes built after 1960 have. Plaster and lath walls, common in older neighborhoods like Congress Park, Park Hill, and Baker, are a different story. Plaster is harder to cut cleanly, and the lath strips behind it can snag fish tape and make routing unpredictable. Concrete and brick walls — found in basements and some commercial-to-residential conversions — require masonry-rated tools and surface-mounted solutions like raceways or conduit rather than in-wall routing. Before any cable project, identify what your walls are made of. Knock on the wall: drywall sounds hollow, plaster sounds solid and dense. If you are not sure, an experienced technician can identify the wall type quickly and recommend the best approach for your specific situation.
Planning Your Cable Route
A cable does not just go from Point A to Point B in a straight line through a wall. Between those two points, there may be studs, fire blocks, insulation, plumbing pipes, electrical wiring, and HVAC ducts. A good cable route avoids all of these obstacles — or at least accounts for them. The most common routing strategy in a finished home is to go up into the attic, across the attic space, and back down the wall to the destination. This avoids having to drill through multiple studs and navigate the cluttered interior of wall cavities. In homes with a basement or crawl space, routing down and across the floor joists is another clean option. Interior walls that run perpendicular to floor joists can be tricky because the cable needs to cross multiple joist bays. Exterior walls are often filled with insulation, which makes fishing cable more difficult but not impossible. Plan the route before making any cuts. Identify where the cable will enter and exit the wall, what obstacles are in the path, and whether attic or basement access is available. Professional wiring services include a route assessment as part of every project.
Permits and Code Considerations
Low-voltage wiring — which includes Ethernet, HDMI, speaker wire, and coaxial cable — does not require an electrical permit in most local jurisdictions. These cables carry minimal voltage and are not considered a fire or shock hazard the way high-voltage electrical wiring is. However, there are still code requirements to follow. Low-voltage cables must be CL2 or CL3 rated for in-wall installation. Running a standard extension cord or non-rated power cable through a wall cavity violates building code and creates a genuine fire risk. If your project involves adding a new electrical outlet behind the TV — which is common for clean TV mounting installations — that portion does require a permit and should be handled by a qualified electrician. The distinction matters: running an HDMI cable through the wall is a low-voltage project with no permit needed, but adding the power outlet next to it is an electrical project that follows different rules. TV Solutions handles the low-voltage side of every installation and coordinates with electricians when outlet work is part of the project.
Avoiding Common Mistakes
The most frequent mistake homeowners make when running cable through finished walls is cutting openings before fully planning the route. A hole in the wrong spot means patching, repainting, and starting over. Always verify stud locations, check for obstructions with a scope or inspection camera, and confirm that the cable can actually reach from the entry point to the exit point before cutting. Another common error is using cables that are not rated for in-wall use. Standard HDMI cables, for example, may not carry a CL2 rating — and while the practical risk is low, it can become an issue during a home inspection or insurance claim. Using the right cable from the start avoids problems later. Finally, do not underestimate how much cable you need. Measure the route, add 20 percent for slack and turns, and buy accordingly. Running short mid-installation means splicing or starting over, neither of which produces a clean result. If your project involves multiple cable types or complex routing through a finished home, schedule a consultation with TV Solutions. Transparent pricing means you will know the full cost before any work begins, and every installation comes with a Lifetime Service Guarantee.