Contractor Talk - Professional Construction and Remodeling Forum banner
1 - 17 of 17 Posts

·
hack of all trades
Joined
·
1,144 Posts
Discussion Starter · #1 ·
Ive been working on an apartment remodel in an old plaster and lath building. Running electrical, I'm having to fish emt through the walls, which sometimes requires cutting a 1" wide channel all the way down the wall, through the plaster and lath. This has been leaving those areas of the wall feeling less stable, being that some of the lath is not longer running tight stud to stud. I've been snapping plumb/level lines, carefully removing the plaster along them, and then cutting the lath with a circular saw to avoid the vibration of a sawzall. Does anyone have recommendations for ways to stabilize the plaster when I get around to patching up? It's tough with plaster because once it loses its original bond with the wood lath, you cant just pop a few screws through, you kind of need to replace it. Any tips?
 

·
Registered
Remodel
Joined
·
30,124 Posts
This is going to be a pain. The best thing to do is when you first go in, take off ~2" of plaster both sides of the cut (one side if you're following a stud), then do your cuts. The lath has to be attached to something, and to do that you have to take keys off the back, so that part of the plaster has to go - it won't be locked in any more. Normally you can slip a 2X3(? sometimes 2X2, sometimes you have to use a 1X) in to nail the lath to, but your trenches are a little narrow for that, so you have an option of building up something in place to get the stiffness you need. Most of the details of what is going to work for you depend on access at the top and bottom of the wall, or having a stud close by to tie to. The bottom of the wall usually has a good pile of plaster and broken off keys to get in the way of anything you do.

You can always foam everything solid as well, as an added measure.
 

·
Registered
Joined
·
77 Posts
Once the lath is severed, it is considerably weakened. You need to stabilize what plaster is left. I use adhesives and consolidant. Big Wally's Plaster Magic works well. Try to buy a contractor pack for best value. If you want to avoid taking back to the studs, you will need to do some join from lath end to lath end. With the adhesives you should be able to get by with out doing every lath; every other lath should be enough to support what is there. You can secure metal lath in between and fill. You will probably have to take some additional plaster off to get some exposed lath. I would leave the plaster edge jagged since it is easier to hide the seam. You are wise to avoid the sawzall.
 

·
hack of all trades
Joined
·
1,144 Posts
Discussion Starter · #4 ·
Im thinking that I should really be cutting all areas open from stud to stud so there's no floating sections, then patch with drywall furred out on the 3/8-ish lath leftovers. It would give me a lot more room for installing conduit and boxes and drilling studs. I'll look into those adhesives, I've never seen anyone use those, but sounds like a good option when it's needed. Thanks
 

·
Registered
Joined
·
2,745 Posts
Is the plumbing and HVAC being remodeled at the same time?

Is there a repeating floor plans that would lend itself to the 3-D design process on the remodeling of the utilities for shared access paths?

Could get together and share new utility chase(s) or split the sub-sub demo/relather/plasterer?

Fiber-optic pinhole camera systems?
Wet/ damp plaster saws?
 

·
Registered
Joined
·
1,214 Posts
Can you use flex? if so then all you need is a 4" hole saw
it may cost more in material but will save alot of labor, yours and the plaster's
 

·
hack of all trades
Joined
·
1,144 Posts
Discussion Starter · #9 ·
In a remodel situation where the walls are not already being opened you can use flex, and shorter whips are allowed in new work; since there were several walls that were being resheathed with drywall and a lot of patching was being done already, we decided to stick with all emt. Running additional home runs, we were able to send conduit down to the basement through a pipe chase.
The last electrical work done was flex pinned between the old plaster ceiling and new 1/4" drywall and a lot of it had been spliced behind the wall at the ceiling corner. Almost none of it had box connectors.
 

·
Registered
Joined
·
6,819 Posts
In a remodel situation where the walls are not already being opened you can use flex, and shorter whips are allowed in new work; since there were several walls that were being resheathed with drywall and a lot of patching was being done already, we decided to stick with all emt. Running additional home runs, we were able to send conduit down to the basement through a pipe chase.
The last electrical work done was flex pinned between the old plaster ceiling and new 1/4" drywall and a lot of it had been spliced behind the wall at the ceiling corner. Almost none of it had box connectors.
ahhhh, we don't need no stinkin' junction boxes :laughing:
 

·
Registered
Joined
·
9 Posts

·
Pro
Joined
·
2,138 Posts
senorfish said:
Best plaster repair technique I've seen is from Scott at thecraftsmanblog.com. He says to resecure plaster with broken key, use the Grip-Plate type plaster washers. They pull everything up tight, can screw into just the lathe, or the studs. Both options work. Float it with some mud and bam you're done.

http://www.amazon.com/GRIP-PLATE-Plaster-washer-100-count/dp/B00IMG3O4S/ref=sr_1_10?ie=UTF8&qid=1403326354&sr=8-10&keywords=Rodenhouse+Inc
These plaster washers work very well.
Only thing I would add is :

Pre-bore the old plaster slightly below the surface, where you want to put the washer with an old 1 1/4" spade bit, ( to make it a little easier for the finisher to cover) and hit the studs. Driving these into just the lathe is hit or miss ( even when you hit the lathe, they don't always drive tight )

- Scott
 

·
Registered
Joined
·
2,745 Posts
Window shopping the big Box, Lowes, A double action two bladed reciprocating saw was being sold for 99$, One blade goes out, adjacent blade comes back A lot less shaking........Crazy smart, think even in surgery.....

Similar to the counter-rotating dual bladed skill saw....?

RE: plastic washer(no rust) acrylic, flexible and sticky, grind out divot, screw washer to lathe or stud to secure loose plaster chunk fill over washer/screw?
 

·
Registered
Remodel
Joined
·
30,124 Posts
Not familiar with this method.

Got a link?

- Scott
Here's one place you can get materials - he's very pricey:

http://www.plastermagic.com/

Basically, it uses an acrylic conditioner and an acrylic adhesive. Driill holes for getting the conditioner and adhesive in, pull tight with the plastic washer so it doesn't stick. Let dry, remove washer, fill holes, done.

Here's a similar GSA spec which gives less expensive materials choices (but doesn't use the plastic washers):

http://www.gsa.gov/portal/content/112122

And a quick note with no details:

http://www.thisoldhouse.com/toh/article/0,,195050,00.html
 

·
Registered
Joined
·
36 Posts
In my experience with plaster I have mostly used flex and cut in boxes, though in commercial settings I've usually cut stud to stud for EMT. Another reason for that is We've usually paired it with a communications drop as well.

Never seen the washer method, will have to research into that.
 
1 - 17 of 17 Posts
Top