sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Cabling Telephones Systems Wiring Plaster Walls

Got a rookie question for ya- We're planning on drilling through a plaster wall to install(1) cat 5e cable. Ordinarily, this is not a big issue, but after meeting the maintenance guy who explained he was THE MAINTENANCE MANAGER and put on his white gloves for inspection, started spouting codes, and then accused us of making gouges on the tiles (we used bare hands to open the tiles), I want to be careful.

I have never had it happen, but I have heard techs talk about plaster walls cracking when drilling. Can this occur? Do I need
to use a certain drill bit to be sure I don't crack?

I'll start with a small pilot hole, drill bigger to 1/2" and put a small conduit sleeve in to make a legal firestop. I have already typed a written release for customer.

Thanks

Plaster walls can be tricky if its an old building with wood laths. If the plaster has got old and brittle it can break away from the lathes very easy. Drilling may not be an issue but if you try to cut a hole in loose plaster it can fall off in large chunks.

When I see a maintenance guy giving me a hard time, I have the customer get someone to drill the hole. Especially when drilling big holes into slabs to get to a basement or second floor. Electricians usually will do the work.

I hope your release includes who is responsible
to repair the plaster walls should your 1/2 hole become a 2 foot x 2 foot broken section of wall as well who will patch after your done.

Also that the release in executed prior to you
touching the wall.

Good luck

OK. I told customer to have electrician install a conduit sleeve. Thanks guys.

If you have to drill plaster, use a sharp masonry bit (the smaller the better). Use a fast drill and put no real pressure against it, just let the drill do the work. As you progress through larger bits, inspect the condition of the plaster through the hole - if it is starting to separate from the lath from age, then there may be nothing you can do anyway. Also, if the lath is metal, drilling a large hole can be really tricky because you don't want to snag the metal lath with the drill. In the past I have drilled a circular pattern of small holes, carefully dug out the plaster, and then cut the metal lath with snips (PITA).

Ancient plaster can be quite fragile indeed, and I sure wouldn't want to touch it with Felix Unger looking over my shoulder, so telling them to get someone else to do it was probably a good idea.

Jim
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Speaking from a secure undisclosed location.

I like the electrician idea. That was going to be my suggestion. Make the customer take responsibility for their own buildings and walls.

I've helped on remodeling at my mom's work where we had to run MC cable through thick plaster walls for electrical. A drill and chisel and then mud over it works okay. Not the best though.

Dunno, I've never had a problem with plaster walls. I can't imagine one "cracking" unless either you smack it with a hammer or it is so deteriorated it's already falling apart. Never used a masonery bit unless the "plaster" really isn't plaster but stucco. Normal tools are regular twist drills, hole saws, keyhole saw and an old screw driver smacked with lineman pliers to chip the plaster off the lath. The latter when cutting in a box for electrical outlets, switches, etc.

So unless this was very old deteriorated plaster from centuries gone by, a hole saw should work just fine.

-Hal

I like to apply blue masking tape over the area before drilling or nailing. I'm sure you've seen it...it's an easy-release tape preferred by painters.

Cover the area to be cut or drilled with said tape and take the above precautions. Make your hole or cut, then gently peel away the protective mask. This technique relieves the tendency for "starter" cracks to spread and cause further damage.