PDA

View Full Version : Surgical Plaster Demo



Matt Kiley
10-24-2004, 07:42 PM
I’m faced with a project that will require creating new doorways in 2 inch thick partition walls in a 50 year old high-rise. The walls are two coat vermiculited plaster with metal lathe, metal tracks run the length of the wall. The new openings will have no trim, just a square plaster detail. One of them is perpendicular to an aluminum framed window, the other is a foot away from a finished travertine shower. I’m thinking of kerfing the wall, carefully breaking out the plaster on the demo side, then using snips to cut away the lathe. I’d prefer to use a recip saw for the final stage but I’m worried about vibration. With a metal cutting blade should I be? I’m also concerned with how to handle the intersections at the ceiling without damaging surrounding areas I want to keep.

What is the correct method to install base over plaster? When I pulled the existing base it was obvious that most of the fractures in the wall began with screws and nails.

Thanks for any insight,
Matt

HenryP
10-24-2004, 08:13 PM
Matt:

Could those "metal tracks" be rebar and tie wire with wet wall?
Are the floors parquet on mastic on concrete?

Sounds familiar.

If these walls are 2- 2 1/2 inches thick, it sounds like a monolithic application and I don't know if you will be able to "strip one side" only.

In any case, if it's rebar frame with tie wire or "metal track", I would use a demolition saw to cut the openings. Use the sawzall only to finish the cuts at the floor and over cut at the heads. Place the building and management on notice because you will set off smoke and fire alarms for 3 floors in both directions.

Better check the clauses in your contract, that travertine shower sounds like it could set you back a few bucks. Protect yourself on this one with plenty of communication.

John McElwee
10-25-2004, 01:54 PM
Is there one layer of lath only with plaster on both sides? 3/4" channels vertically or rib lath installed vertically? I would worry about vibration with a reciprocating saw. The dust from a circular saw is unbelieveable. I think use a saw and cut completely through the wall. Maybe use a recip at the top and bottom where the circular won't cut. I think cutting at the wall/ceiling angles will be pretty neat too if you can do it. On the other hand. A good plasterer can make almost anything look right if your cuts are off or ragged.

Matt Kiley
10-26-2004, 12:24 AM
Thanks for the replies guys,

Starting from the center of the wall - ½ inch of what looks like a pre-formed gypsum panel with brown paper on both sides, Diamond mesh lath, scratch coat, veneer. I’m thinking that the channels on the floor and the end of the wall somehow grip the panel and everything goes from there. Vibration is really my primary concern - unless metal lath is more forgiving than wood, I'm betting a Super Sawzall will do some damage.

Coming from both sides - circular saw through plaster, angle grinder with a cutting wheel through lath, demo saw through panel?

Matt

John McElwee
10-26-2004, 07:02 PM
Why not use an abrasive blade and go through everything in one cut? Is the daimond mesh lath on both sides? Is it over the whole wall or only joints in the panels and at the angles? You must have made some cuts or you wouldn't know the construction of the wall. What did you do and how did it work?
I think you are trying to make this more complicated that it is. I, too worry about vibration from a sawsall. That would be my last choice. I've actually had good luck cutting with a hammer and mason's chisel. But I am a plastererand can can fix any irregularities or broken plaster. Just figure out the best way--either a demo saw which would not be my first choice or a circular saw and cut through.