Help me wire my basement office for sound

October 2, 2008 3:29 PM

How difficult is it to run low voltage wire perpendicular to the joists, in a finished basement, with minimal damage to the existing plaster?

I want to add two ceiling speakers and an outlet with ethernet and coax jacks in a basement room. The walls and ceiling are lath and plaster but the lath is a keyed gypsum board called Rock Lath (just like drywall). There are three joists (5 feet) between the speakers. The outlet will go in a wall cavity that more or less sits in the same area as the joist cavity of the right speaker. From that joist cavity there are an additional 3 joists that I need to go through and then up to the main floor equipment closet.

My initial thoughts were to cut a hole in the ceiling above the outlet in the same joist cavity as the speaker and another hole under the equipment closet. I want to use use a flexible bit between the two speakers to run speaker wire from one to the other and then down the joist cavity to the hole in the ceiling. I'd use the same flexible bit to go up the wall, through the header to run wire from the ceiling to the outlet box. Finally I'd drill through the joists between the two holes in the ceiling and then up through the footer of the upstairs wall.

I have a few questions about the plan:

1 - One of the joist cavities I need to go through is a cold-air return. There is no plenum, just the joists and the lath/plaster. I can get to this particular joist cavity from an upstairs return vent and can see that there already are electrical wires running across the cavity (not down). Am I going to be ok running low voltage through this cavity as well? I'll keep the low voltage wire two feet from the electrical.

2 - How about using the flexible bit across the joists? Does it seem practical? Are there any gotchas I need to be aware of? As far as I can tell, other than the cold-air return mentioned above, there are no HVAC, plumbing or electrical obstructions between speakers or between the outlet wall and the equipment room.

3 - Can you think of any better way to do this or anything I'm missing? I really want to minimize damage to the plaster as suck at repairing it.

Bonus - I'd really like to run some flex-conduit to make this a little more flexible down the road but the flex bits seem to max out at 3/8 which is not big enough to run conduit that can hold the amount of wiring I need. Are there any other options?

posted by toomuch to home & garden (4 comments total)

I've been thinking about a similar problem, and have been eyeing the products from here - basically they have flat wire that can be run over the surface, then plastered and painted. They have speaker, and I believe ethernet. I cannot speak to the quality of the wire, myself, but it seems like a good solution
posted by deliquescent at 3:43 PM on October 2, 2008

Here is a place that sells half and three-quarter inch flexible conduit. At work, in our wiring closets, I have seen larger...perhaps not readily available at Home Depot, but it does exist.
posted by mmascolino at 6:49 PM on October 2, 2008

I'm having a hard time understanding from your description, but that's because it's been a long day---not because it's not clear.

Depending on the age of your house, there are likely firebreaks in the walls between joists, it's not always as easy as running crap down between them. There's also often fun stuff in there like old nests, random junk they stuffed in there when they were building the house (we've found clothing, blankets, boxes, tools, etc.).

I would see no problem running speaker wire through the venting cavity as I understand what you have said.

Something to consider:
It's pretty easy to make a drywall-plug in a wall hole. Cut a sizeable hole between joists where you want the box to go so it's not hard to find, run the cable down from above, and then mount the rectangular piece of drywall between the joists with the box in it or on it. You can even use magnets/velcro if you want to, and decorate it or obscure it however you want to---you don't have to truly finish the drywall if you don't want to.
posted by TomMelee at 7:51 PM on October 2, 2008

The easy way out would be to use discretely placed wire mold--near the baseboard or ceiling--for the horizontal runs. I know it's not as elegant as going through the wall, but at least you wouldn't have to mess with the plaster. Good luck.
posted by paulg at 8:50 AM on October 3, 2008