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This FAQ is intended for professional installers and Do-It-Yourselfer's who are contemplating installing their own security system. The opinions expressed here-in are my own. We welcome your comments and suggestions.
Please note: My thanks goes to Robert L. Bass at Bass Home Electronics for providing the inspiration for this FAQ.
How does an installer run wire inside a wall without having to damage the drywall? (The answer applies to most homes built in North America today). For lathe and plaster walls, this method may NOT apply. Email us if you need help with an unusual situation or if you're wiring in an older home (pre 1970's vintage).
Tool Tip
You'll need the following tools and equipment:
There are several methods used. One involves removing the baseboard but if there is none (or the baseboard isn't wide enough - minimum 2"), access to the wall's top or bottom plate (from either the attic or the basement respectively) is required (unless you want to do some minor patch and paint work). If you plan on running the wire up from the baseboard, you'll need a sharp utility knife to "cut" the paint on the board away from the drywall first. Attempting to remove the baseboard without first doing this could result in damage to the drywall from the paint adhering to it and peeling away unevenly. I prefer to use a wide putty knife to get in behind the baseboard and gently prise it away from the wall. Sometimes the nails actually pull right through the board (remain stuck in the walls base plate). If that happens, you'll have to remove the nails (use the 3/4" plywood board to protect the sheet rock when you're pulling the nails with the hammer or use a pair of vise grips to grab the nail and pull it out). Once it's removed, lay the baseboard aside, nail-side down against an adjacent wall (not in an area where it may be a hazard to foot traffic). Use a stud finder to locate the vertical studs in the wall in the area you wish to install the device (motion sensor, keypad, glass break).
Insert the tip of your drywall saw about 1 1/4" above the floor (you may have to peel the carpet back slightly to expose the floor). Cut horizontally along the wall's bottom plate about 1". Make another horizontal cut about ½" above the first. Make sure your top cut is below the level of the top of the baseboard (easily discernable once it's removed). Now make two vertical cuts between the two "ends" to remove a section of drywall that's 1" x ½".
Insert your fish tape and push it up the inside of the wall with the hook end facing *away* from you (this will prevent your scoring the vapour barrier behind an outside wall). It's a good idea to put a slight bias in the tape so that it runs up against the inside of the drywall. That way you can hear it progress up the wall. If you're able to push it all the way past the third tape band (6' mark), you're home free (in the case of a motion detector or glass break).
A comfortable viewing height for most LCD keypads is between 4 ½' and 5'. Drill a 3/8" hole at the height you want to mount your motion sensor or glass break and push the wire into the hole... If the wall is insulated it should bunch up around the hole. You can snag a section with the fish tape and pull it down and out of the hole you've cut under the baseboard. For most keypads, I cut a 1 ½" square hole as it's my practice to run two four conductor wires to every keypad. I carry a role of vapour tape that I use to seal off the hole the saw makes in the vapour barrier after I've finished running the wire.
If you plan on running the wire you've pulled out along the edge of the room/wall you'll have to gouge out the drywall under the hole you've cut to get to the floor. Trim enough of the drywall away so the wire lays flat and won't interfere with the baseboard. It's a good idea to gouge it out to expose the bottom plate to make drilling into an open basement or crawlspace easier. If you plan on running it into an open basement or crawlspace under the wall, then you can drill down using a 3/8" drill (position the tip right against the exposed bottom plate).
Replacing the baseboard is pretty easy. Carefully hammer the nails/staples out of the board or you can use the plywood block to gently tap it back into place using the existing nail or staple holes. With the former method, you'll need the spackle to properly "finish" the job and paint to touch it up. With the latter, you should be able to get the baseboard back into place with no nail pops to fix.
Tool Tip
Top/Bottom plate access requires the following additional tools/equipment:
Caution: Never step directly on the exposed or insulated drywall ceiling in the attic, or electrical boxes and cable. Always step carefully on either the wooden joists or the top plate of a framed wall. If you're going to be working in the attic, do so early in the day (when it's coolest). Plan to do all your runs at once so you won't have to stay up there very long. Attics can get extremely hot. Avoid excessive exposure to this kind of environment (take frequent breaks, drink lots of water). Work safely! Always wear proper protective footwear!
For more information on running wire in an attic, click here.
Using the stud finder, locate the cavity you want to run your wire into. You can predrill a hole for a motion or glass break detector, but I wouldn't recommend this unless you know you have positive access from either the attic or the basement.
Some installers like using the paddle type bits, but I've encountered nails in some top and bottom plates that would wind up creating a major problem for you if you accidentally hit one (sometimes the framers will break or bend a nail and it won't be easily discernable). In the attic (wear the coveralls and dust mask as glass fibre insulation encountered in most modern homes can be irritating) you can usually identify the wall's top plate by several methods. One is to watch where the electrician may have run wires for switches and fixtures into the same wall (easy), and the other is to clear the insulation away from the suspected area and actually look for it. In most homes with frame and drywall construction the top plate is actually exposed in the attic (usually sandwiched between the ceiling drywall).
Some top plates will have a second plate that's slightly offset from the first. This acts as a nailing point for the drywall. Watch how the electrician has drilled his holes in this type of situation or you may inadvertently make a hole in your ceiling if you're not careful. Since most homes use 2x4 construction (for the interior walls) you don't have a whole lot of room for error. Vertical studs can usually be identified by the nail pattern (16" centers) you'll see on the plate... Have someone rap on the ceiling. They should hold the piece of plywood on the ceiling or section of wall adjacent to the ceiling where you want to mount your detector or keypad and hit it lightly with the butt end of a screw driver. You should be able to mark the position fairly accurately. You'll also be able to tell on which side of the stud you're going to wind up as well. Drill down into the wall cavity and run your wire into the hole you've made.
TIP - You can run the marked 10' fish tape into the wall and make sure it's clear of fire-stops down to the level of the device you wish to mount first.
Now drill the hole in the drywall where you're going to be mounting your detector (motion or glass break). With the short length of steel tape you can fish the wire out of the hole that you've run into the wall cavity. For a keypad, cut the hole in the drywall at the height you want to mount it and use the longer length of fish tape to pull the wire out.
Sometimes, bottom plates are a little harder to find (some inside walls). In an unfinished basement or crawlspace, you can usually see the nails the framers used to secure the bottom plate, but if that isn't possible, a quick method to find the wall is to use a small drill bit (1/4" x 18")... Pull the carpet away from the baseboard (you don't have to remove the baseboard with this method) and drill a hole into the floor right against the wall and adjacent to the cavity you've identified with your stud finder. With the longer bit you can angle it so that the drill doesn't touch the baseboard but goes into the floor right against the wall. Pull the drill out and insert a short piece of 4 conductor into the hole. You should be able to find it easily in the basement. Orient yourself properly so that when you measure 2" from the hole you've made, you're right in the wall cavity. Drill up using the 3/8" bit and fish the wire using the same method as we outlined in the baseboard. For keypads try to stay away from mounting them on outside walls if at all possible (it'll make your job a lot easier).
For wiring windows and doors, click here.
Copyright © 2003 by Frank Olson
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Last updated:
October 19, 2003
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