[TriLUG] Information on running CAT5 in exterior walls

[Heath Roberts]

On Thu, Jul 28, 2011 at 1:19 PM, Bill Vinson <bill at vinsonweb.com> wrote:

> Given some of the discussions recently, I thought I might be able to get
> some helpful suggestions from this group... We just recently moved into a
> new house & I am looking to wire several rooms up with CAT5e/6, but I'm
> running into an issue. I can easily run cables through the attic or
> crawlspace, but connecting the two is causing me some issues. I found where
> the TWC coax lines run from crawlspace to attic & had assumed I would be
> able to fish cables by trying to lead in & follow the same path, but I'm
> hitting stud, heavy insulation, or something (possibly the hole these
> cables
> run through is just too small to accommodate additional lines). The old
> house was easier as I could run from the crawlspace through the garage &
> unfinished storage above the garage without every dealing with insulated
> exterior walls...
>
> Does anyone have any suggestions for next steps or am I just needing a
> professional at this point (I'm not handy enough to open the drywall & then
> repatch/paint)? If I do need to go the professional route, does anyone have
> any recommendations they'd care to offer? I have no idea what kind of cost
> I'm looking at, but I want to weigh all options (including professionally
> finished wiring, or bridging wi-fi, or powerline networking, etc.)
>

It's usually easier to run wire in a overhead space (attic), because you
don't have to
worry about the beam supporting the wall you're trying to get into.

Since you have access to the crawl and attic spaces, you could just put in a
large
chase (PVC pipe, etc.--please use the gray electrical one) between them. The
biggest
problems are usually figuring out where to drill and getting around
obstructions in/under/on
top of the wall. You typically want to find a stud bay that has no wiring or
plumbing, and that's
in a wall that runs perpendicular to the floor and ceiling joists. Exterior
walls are almost
always going to be insulated and will most likely have blocking, so it's
usually easier to
run wires on the inside.

One way to locate a good spot to drill is to use something like this:
http://www.lsdinc.com/content/product_details/18#
to make 'locator' holes close to but not in the walls.

and here's an example of how you can deal with insulation

http://www.magnepull.com/index_010.htm

A youtube search for "fish wires through wall" turned up some potentially
helpful videos as well.

Overall, though, running wiring inside existing walls isn't usually easy.
I'd hire someone who does
it all the time (they're not easy to find, though), and if you're worried
about cost, maybe offer to
be a helper for the day.

It's also cheapest if you can plan ahead to have a whole day's work for
them, and know exactly
what you want where.

-- 
Heath Roberts
htroberts at gmail.com