Wiring 2-Story home


Senior Member
Hey Guys,

I need some tips here... I recently moved into a new 2-story house and I need to get my Elk and all the fun stuff hooked back up (TStats, keypads, etc). I'm great at wiring single story homes and commercial spaces, but I've never done anything with a 2-story home before.

In my neck of the woods, there are no basements; the houses are on a concrete slab... so no way to get from below.

So here's the question... What are the tips/tricks and other important things to know about passing from one floor to the next? One example is the thermostat location - It's on a wall that is open all the way from the first floor to the second (same wall as the pantry). Also, in the media niche it could use some Cat5 - and I need to get some Cat5 from the "His Closet" into the garage. "His Closet" is where the home's structured wiring already goes and all the new wires must run to.

Can anyone share some tips and/or pictures of how their homes were wired? I guess what I'm not sure of is if you'd normally just drill straight through the second floor into the wall cavity of the first (think that tall wall). What would you want to avoid drilling for structural integrity and other code reasons (fire, etc)? I'm OK with doing a little drywall repair where necessary if I need to cut guide holes, or a hole to let me get my drill in the wall.

My big concern is the bigig stacked-wall - that's got to be a support beam of some sort there - how would you get through that, or do you have to go around somehow?

Any pictures of how wiring was run between floors pre-sheetrock would be awesome too.

Thx guys!


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I have a colonial style two story in the MW. The front entrance walls expand from the first floor to the second. I also have a basement. I used this common wall to wire from the basement==> main floor ==> second floor = => attic.

Looking at your drawings my wiring wall would be similiar to the wall adjacent to your stairs in the middle of your drawings. Looks like all your cabling would have to be done mostly from the attic down (similiar to my setup in FL). What is difficult is that you have no basement. Do you have access in your attic to all of your interior walls and some exterior walls? IE: I have a steep pitch for the roof over the second floor. The attic is about 8-9 feet high in the middle. With the large open space in the attic I can walk to any of the areas of any of the rooms. How is your HVAC configured? Is it in the attic?

I do not have cross members in the middle of the interior walls (fire breaks?). In FL the home is a ranch style with 9' or more (vaulted ceilings) and no basement. I can only pass wires from the attic down. I have one central point that I use from the MM/HAI box to the attic then down to rooms. Its difficult because of blown in insulation in the attic and all the walls have fire breaks about 5 feet up between all of the studs.

To help me with the wiring some I installed in wall speakers and an access panel on the second floor.

Main floor foyer has an in wall speaker once removed giving me access to drilled holes to the second floor in between wall stud cavity. On the second floor in one bedroom behind some furniture is an access panel I made which allows access to cables / pulling cables from the 1st floor cavity by the in-wall speaker. At the top of the second floor foyer I put another in wall speaker. This allows access to the area where the access panel is below and allows access to the attic space.

Not sure if my description makes sense. With the access panel / speaker holes (X2) its easy to pass cables from the basement to the first floor to the second floor then attic. All of the wiring form the 2nd comes from this cabling run.

I looked at your pictures for common 1st and 2nd floor walls. I did an overlay of the second floor to the first floor which might help you some.


Senior Member
When I built, I had a chase added so I can get from my wiring room to the attic, then from there, I just drop into whatever room I am trying to get into.



Active Member
You definitely need an attic of some sort to guide the wires to each section of the house you want to wire. It is sometimes surprising difficult to drill and run wire horizontally through any wall for more than 3 studs (unless you have giant cutouts on your drywall like for speakers), so you need an open place just to drop the wire where ever it is needed. I'm thinking there's got to be something under the eaves of your home. Generally you need one good route out from your structured wiring panel (or where ever).

One thing I noticed from your pictures is that a lot of the spaces you may want get into have closets. It's not always the prettiest solution, but it is WAY easier to drop down into a corner of a closet. For instances, drop from the attic space into a second floor closet and then down to the first floor. Otherwise, I would suggest taking into account all the outlets and switches, maybe remove the power switch and see which direction the power lines go and use the hole where the jbox is (if it's a retrofit jbox) to drill holes through ceilings and floors. Every drop will be different. Avoid plumbing walls and exterior walls when possible.


Active Member
I was putting new flooring in and took time to put my wiring in at the same time. Rather than cutting holes in the drywall, I cut holes in the second story floors and used that to drill holes in the top plates of the walls and run the wiring on the 1st floor.


Senior Member
Hey Guys - I'm picking this back up finally...

Today I'm putting in the CV can and hopefully taking care of a few of the important main runs - especially the upstairs stuff...

Question - when going from a second floor to a first floor, do you just drill right through the base plate all the way down? Anything weird you have to do there? I'd really love to see some pics from peoples' wiring passing floors from when walls were down.

I do know it's easier to run wires in front of walls - but I just can't do it. I'd rather cut the wall open - but only where absolutely necessary.

Wish me luck - if anyone could provide some tips before I get down to it, it'd be helpful - I'll be looking to do a few of the big runs to the first floor in a few hours.

BTW - this is a 5yr old house that's never had anything done to it since it was built... so they're all new work electrical boxes, no floors to replace, etc. And I hate wire under the carpet.


Senior Member
If you provide specifics, would be easier to suggest tips. ;)

This write-up was posted recently at AVS - loaded with good tips



Active Member
As far as drilling between floors, there is no structural concern as long as you don't go crazy with it. After all, that's how the electricians do it. Just don't drill the holes much larger than what you need for the cables to pass comfortably through without binding, and you'll be fine. It's not a bad idea to get some fire-retardant caulk and fill the holes after everything is pulled.


Senior Member
Using a Flexibit-type bit has kept me from most major drywall repairs. You can drill through the floor/bottom/sole plate from outlet or switch height cutouts.

Find a helper. I've been doing all my retrofit cable pulls solo, and it's VERY difficult, for soffit pulls. The dangling cables to the floor are just too heavy.

A 2nd ladder would also be helpful, but depends on what you're doing.

Pulling baseboard is easy for horizontal runs.

Make sure the Flexibit is perpendicular to the board you're drilling.

Bundle cables with electrical tape while they're entering the cutout, but don't tape the extra pull string (for future pulls).

Add a pull string when you think you might want another cable in the future. I've been using mason's line.

Add an extra cable or 2, in places where it might conceivably be needed in the future. I pulled a cable bundle last night with 11 cables, from 2 audio zones (cat6 x 7, 18/2, 22/4, 16/4 x 2). KPs will be in the garage (future alarm and phone uses for extra cables), and next to the back door (door bell, additional contact sensor).

Don't drill into a space blindly. Obstructions include Romex, other LV cables (phone, alarm, coax, audio), central vac pipe and cable, vent stacks, copper plumbing, vapor barrier. The line voltage wires worry me the most, because I don't know where wires could be running to reach the upper floors.

Keep your holes small, e.g. single gang, so you can cover them with a plate affixed to a low voltage bracket until repair is done.

Let new work boxes drop into the wall when you remove them, unless they'll interfere with drilling at the bottom of the stud bay. When you pry them away from the stud, always move your pry bar or screwdriver AWAY from the stud. Similar approach for baseboards - away from the drywall.

I've never mistakenly drilled into something that I really shouldn't, but most of the other stuff I've learned the hard way. ;)

Don't pull cables through a drywall cutout without a helper or without a LV bracket. The cables will rub against the drywall and very quickly carve a groove into the edge of the cutout.


Senior Member
Trying to drill from the attic all the way down to the first floor is going to be tough. You can put the 4 foot flex bits together but passing it down 8 or more feet from the attic to the floor plate of the wall below and then through that to the first floor walls is likely to not work. Plus you may nick water pipes, electric wires, or accidentally pop out the wall.

Fire blocking is usually only for 10 foot walls. And if you don't drill big holes the fire code shouldn't care, but you would have to ask your local guys.

Tricks like pulling base moulding off and using crown moulding to run wires helps a lot. If you don't have crown moulding, consider adding it and run the wires there. On uninsulated walls it is pretty easy to cut a hole at the top where it will be covered by the moulding and drop your wire from the top down to a box lower in the wall. Use closets to your advantage and try to cut holes in the drywall there so patches aren't visible.

If you are taking up carpet, you can use a router to cut a small channel in the subfloor and lay LV wire in there. If you don't have a wood subfloor you can run thin wires under the carpet but you might feel them if the carpet/padding are thin. It is not the greatest but it works. I did this (cut a groove) for speaker wire when I was a teenager many many years ago in my parents house. It still worked perfectly 20 years later when my parents sold the house.


Senior Member
Thx guys - I read the tips over the weekend too, but was on my ipad and I'm too stubborn to make the required changes to my profile to be able to respond from it...

Neuro - lots of good tips - and that write-up has a lot of great tips - especially for helping people adapt cheaper items for a lot of situations! The weed-eater line and a few others were great tips. I actually have some advantages because I'm fully equipped for commercial runs - so I have flex-rods, poly-line, glow-rods, the long drill-bits, and lots of other handy tools.

I have been really close to compromising on my keypad locations just to keep things easier, but with the baseboard trick, I just might be able to get to the places I want to. I'll look at that closer.

I did venture into the attic for the first time this weekend - and while it's a pretty nice attic (my last one was easier to get around in, but the insulation used traumatized me - I've never been around so much loose fiberglass)... this one is nice and not real itchy, but the insulations is so thick, it's actually pretty hard to dig down and find the actual lower wall structures because there's like another set of beams above that were really throwing me off.

The most scary thing of all for me, is knowing that there's PEX in the walls, so something like 29 individually run water pipes (so they're sure to be everywhere) and fire sprinklers covering the whole place (plumbed with PVC, not metal - since they're residential).


Senior Member
Are there some first and second interior walls that overlap? If so, what I did was add two 2" conduit runs from the attic down. One goes to first floor and into a 42" structured wiring box, the other goes under the house. I had to drill through top/bottom plates to do this. I also added another 42" structured wiring box upstairs with even more conduits going into the attic. Retrofitting 2" conduits is possible if your attic has the clearance; I did mine in 10' sections (it wasn't easy though). The conduits are a real time saver and future proof my installation.

I do plan to go back and add sheet metal anywhere there are holes in the top/bottom plates. I think is required if you go with large conduit in a 2x4 wall? Kind of pointless since the studs will carry the load and not the top/bottom plates... If you can't run two vertical conduits, I wouldn't run 2" conduit horizontal as this would weaken studs that carry load.


Senior Member
Well, I'd never in a million years fit 2" conduit, but the ideas about following the baseboard are really starting to appeal to me. I'm getting much closer to just cutting a few walls, and running wire behind baseboards to get my wires where I really want them.

But, that's pretty obtrusive - so I'll be waiting until after Christmas to start ripping up the walls :-D Until then, a keypad in the bedroom and iPhone control will hold us over.