Cutting drywall and lath and plaster?

[spikfot]

Thanks, Tinker. I hope my nose never knows well, you know-
Stories of Old Masons? -More the merrier!

 

[Sean.M]

Paul, is this something like the routine you are currently doing for repairs?  

1). Remove loose plaster. ( Plaster that is no longer keyed behind wood lath )

2). Patch with board. ( This may require odd geometrical shapes but is easier filling with structo lite)

3). Apply bonding agent: Plaster weld or USG plaster bonder to entire surface.

4). Apply thin coat of Diamond Base coat.

5). Finish with pre guaged lime finish. Like Diamond finish or kal coat.

6). Or you can skim three coats of durabond over it. ( That sucks)

Quote taken from Drywall Tycoon on DWT.

I understand your concerns for a jig saw but I was thinking of a low depth.

 

[JLB builders LLC]

Roto zip sucks for plaster BUT great for drywall and I hold the PC 7812 hose beside it while cutting and have a dust free area. I have had home owners watch in amazement expecting dust everywhere.  I had spent 3+ years on the Ronald Reagan Building doing metal framing and Drywall, and 2 years doing the new Washington DC convention center, Thats more drywall than most people do in a life time and I still have and use the roto zip from there to this day. Great tool for the right job.

I haven't found any one thing to work on plaster/lathe and wood except a 2 lb hammer. Then sheetrock the ceiling.  [wink]

 

[Rob Z]

We've gotten good to excellent results cutting drywall, cement plaster (over  metal lath and blueboard), cement board, etc. with a variety of tools.  

The Rotozip has been one of the best tools when used with the dust collecting shroud and a good vac such as a CT22/26 or even the Midi.  

The Rotozip saw and the Hilti grinder work  well when cutting into a surface which is either enclosed or has something under it ( such as subfloor).  In the picture with the Hilti grinder cutting cement board and tile on a wall, you can see the shop vac is being used to get the dust which exits  from the cavity in the wall.  In the picture of the Hilti grinder cutting away the gypcrete underlayment in a doorway, the Festool vac  connected with a hose was enough to get almost all the dust because the grinder was cutting on a solid surface.

We've had varying levels of success (or failure) trying to carefully cut away the old horsehair and lime  plaster over wood lath.  That is just a PITA no matter how you approach it.

I recently learned about Kett saws.  I like the look of this model KSV 432 (check out the EPA video), although I don't know if it would cut through wood lath with minimal vibration imparted to the wood lath and plaster.  We have a  job coming up soon in a 1930's vintage house which I know has plaster and wood lath.  If I can get confirmation that this tool will cut away the plaster and lath without causing a lot of damage to the surrounding area, I'm going to buy it and put it to use.

Has anyone seen or used Kett saws in action?

http://www.kett-tool.com/product_details.php?product_model=KSV-432

 

[Ken Nagrod]

I'll reiterate a little of what I said previously and expound on it as well.  Typically, when dealing with old plaster walls and ceilings, you'll find any combination of plaster, wire mesh and wood lath.  Personally, I've only come across plaster with wood lath and plaster with wire mesh on top of wood lath or patches of it.  I haven't done any jobs where there wasn't wood lath involved.

On the recommendation of a tech from Rotozip many years ago, before Bosch bought them, it was suggested to try a blade or router bit for the plaster (cement) and then go back and use either a wood type router bit in the same cut or a fine tooth blade to cut the wire mesh and wood lath without pulling on it like a typical demo blade or reciprocating saw blade would do, because of the low tooth count and high hook angle of the teeth.  If you're dead-set on using a reciprocating saw, even though I don't recommend it, go with a metal cutting blade and cut at a very shallow angle to minimize vibration.

Yes, this does add to the time, basically doubling it or more, but you will have to consider the quality you intend for your end result.  I would venture to say that a small diameter saw blade with a high tooth count, low hook angle and diamond teeth or at least a top quality tungsten carbide toothed blade would cut through all materials with very good results.

 

[gkeas]

I've had good luck with my trion and carbide plaster blades. I use it with the trammel for cutting round speakers into lathe/plaster ceilings.

Very little dust in my drop cloth after.

 

[Brice Burrell]

I just picked up the Hitachi CM5SB, about $150 without a blade.  It's similar to the Hilti Rob has in has pictures.  With the blade completely enclosed you've got no vision of the blade so you have to guide it with a notch in the front like that of a circular saw.  Also the Festool hoses don't fit on the dust port all that well, although I'm pretty sure I can figure out a better way to attach the hose.  Dust collection was okay cutting cement board.  I'd say probably around 70% with my (older) CT Mini, D27 hose, with old style paper filter bag.

I'll try to remember to report back after some more use.

 

 

[Alan m]

I just picked up the Hitachi CM5SB, about $150 without a blade.  It's similar to the Hilti Rob has in has pictures.  With the blade completely enclosed you've got no vision of the blade so you have to guide it with a notch in the front like that of a circular saw.  Also the Festool hoses don't fit on the dust port all that well, although I'm pretty sure I can figure out a better way to attach the hose.  Dust collection was okay cutting cement board.  I'd say probably around 70% with my (older) CT Mini, D27 hose, with old style paper filter bag.

I'll try to remember to report back after some more use.

 

do you think that the guard part would fit a normal  grinder

 

[Brice Burrell]

do you think that the guard part would fit a normal  grinder

Alan, I think there is a good chance it might.  It attaches the same way a regular blade does.  Check out this parts schematic, see parts #33 and #34.  I'll try to measure the mounting ring on Monday and that should give you a good idea if it will fit your grinder.

 

[Alan m]

thanks brice. i would love a dc schroud on my grinder for some jobs. lately iv had a few jobs where cutting a few feet of shallow cuts(like grout from tiles) have been 80 % of the total dust [eek]. im sure i could come up with some kind of rail guide or straight edge that would keep it straight and from cutting the tiles etc. maybe a festool rail and 2 geeko clamps.

are thare any other grinder dust colection  schrouds out there.

 

[Ken Nagrod]

thanks brice. i would love a dc schroud on my grinder for some jobs. lately iv had a few jobs where cutting a few feet of shallow cuts(like grout from tiles) have been 80 % of the total dust [eek]. im sure i could come up with some kind of rail guide or straight edge that would keep it straight and from cutting the tiles etc. maybe a festool rail and 2 geeko clamps.

are thare any other grinder dust colection  schrouds out there.

Use a Rotozip setup for cutting out tiles or grout.  Just hook up a CT to it.

 

[Kev]

You guts really need the Protools don't you.

I was messing about with a Protool angle grinder with DC that can plunge on a track like te track saws .. Really cool. Shame I don't see a need for one for me!

 

[FulThrotl]

Any suggestions on a dustless way to cut drywall and/or lath and plaster?

Here's one scenario of older home having electrical and plumbing upgraded. Trades leaving holes around the house.

Currently I use a Fein multimaster with an extractor held close. (cuts better than a rotozip)

Dustless drywall cutter?

i'm an electrical contractor by trade, and there is a tool made for cutting can lights in...
i have three of them, one each set for 4", 5", and 6" can lights.... with a single dust
housing in a #1 systainer.

there's a chinese company that makes them, and sells a number of different configurations,
but it's obvious they come from the same factory. i can cut a 6" cookie in about ten seconds,
and have a vac running so it pulls the drywall dust out of the air, when i pull the thing down
from the ceiling or wall.

there are cheezy ones, but the one you want to get will cost about $80 and will look similar
to this one.... you can get them at most electrical wholesale houses.

http://www.noralighting.com/Product.aspx?pid=8343

i use them for snoodling stuff across ceilings, installing can lights, whatever.... i then take a couple pieces of lath,
screw them across the hole, bridging it, and put the cookie back, oriented as it was before... it's pretty easy to make
the patch match.

they cut plaster ok, they don't like stucco much. don't use them on stucco.

for straight lines, i use a fein tool, with a vacuum hose right next to it, sucking
up the dust.

 

[nanook]

thought I would bring this thread back from the dead and ask about tearing out cracked plaster ceilings? 

The plaster is detached from the lath and down in a few pieces, the lath is then holding up 6-8in of packed insulation in a sunroom w/ a flat roof.  Roof was replaced recently. 
Anyways, looking to pull down the plaster w/o damaging the wallpapered walls if I can. 
Any advice in regards to a grinder vs multi-master vs small circular saw to cut/isolate the ceilings from the walls?    Sounds like a jigsaw or sawsall will just destroy things with the vibrations!  (esp with the plaster louse and ready to fall in places).  Also there is a chandelier mount - so there is probably electrical up there, might even be knob and tube!

The plan right now is to pull out all the plaster and leave the lath and insulation intact for the time being, there is some discussion of sprayfoaming the underside of the flat roof, but then your running into moisture issues.    So right now the thinking is to tear out the plaster and drywall over the lathe, wondering what the best way is to cut a relief cut around the perimeter of the ceiling to minimize damage to the walls?

 

[Floorman70]

Maybe an Exact PS150? It`s small,lightweight(easier for working overhead),up to 14mm cutting depth(depth can be adjusted to suit),has dust extraction,HSS/TCT/DIAMOND blades available

 

[Tinker]

thought I would bring this thread back from the dead and ask about tearing out cracked plaster ceilings?   

The plaster is detached from the lath and down in a few pieces, the lath is then holding up 6-8in of packed insulation in a sunroom w/ a flat roof.   Roof was replaced recently.   
Anyways, looking to pull down the plaster w/o damaging the wallpapered walls if I can.   
Any advice in regards to a grinder vs multi-master vs small circular saw to cut/isolate the ceilings from the walls?    Sounds like a jigsaw or sawsall will just destroy things with the vibrations!  (esp with the plaster louse and ready to fall in places).   Also there is a chandelier mount - so there is probably electrical up there, might even be knob and tube!

The plan right now is to pull out all the plaster and leave the lath and insulation intact for the time being, there is some discussion of sprayfoaming the underside of the flat roof, but then your running into moisture issues.    So right now the thinking is to tear out the plaster and drywall over the lathe, wondering what the best way is to cut a relief cut around the perimeter of the ceiling to minimize damage to the walls?

The roof has recently been replaced.  I am assuming the plaster is sagging because the roof had been leaking.  If the lathe is plaster board or old wood lathe (packed insulation leads me to think it might be old wood lathe.  Modern insulation does not get packed in), the chances are that the plaster is sagging because there has been a change in the lathe as well as in the plaster.

Read my earlier post from two years ago. That plaster can come down all at once as soon as you create any vibrations.  There may have been vibration as part of the breaking down when the roof was being worked on, both from the demo portion as well as the fixin' part.  I would not tackle that ceiling without first shoring or adding over your head protection.  If only sheetrock (some people call sheet rock "plaster".)  I think you know the difference, but just in case, sheet rock might not be too uncomfortable, depending on hardness of head, when it comes crashing down.  Plaster comes in all degrees of weight and hardness.  That stuff can be extremely uncomfortable when wearing, especially when the first realization you will be wearing comes when you notice the decension from three feet below the mass.  [oops] [censored]

In ceiling plaster repairs later in my experience, I never started with any demo work without first setting up A-frame type supports in whatever pattern i felt necessary.  The job you are describing sounds as if you want to be making those A-frames outside of the room and then transporting Verrrryyyyy carefully into the room.  I would advise the client that they should stay out of the room until it has been repaired to the point that ALL plaster ceiling has been removed.  If they try to go in for inspection once you have started, I don't know if doing as i did, and walking off the job would release you from liability.  The rules have changed since the early 50's.  It just seems like a dangerous situation the way you are describing.
Tinker

 

[Frank-Jan]

For the cutting part: both fein and lamello make machines that look suitable.

link to fein
link to lamello version

/edit by "suitable" I mean in this case, quick, dustfree, near flushcut. but they both are very expensive.

 

[woodie]

thought I would bring this thread back from the dead and ask about tearing out cracked plaster ceilings?  

The plaster is detached from the lath and down in a few pieces, the lath is then holding up 6-8in of packed insulation in a sunroom w/ a flat roof.   Roof was replaced recently.  
Anyways, looking to pull down the plaster w/o damaging the wallpapered walls if I can.  
Any advice in regards to a grinder vs multi-master vs small circular saw to cut/isolate the ceilings from the walls?    Sounds like a jigsaw or sawsall will just destroy things with the vibrations!  (esp with the plaster louse and ready to fall in places).   Also there is a chandelier mount - so there is probably electrical up there, might even be knob and tube!

The plan right now is to pull out all the plaster and leave the lath and insulation intact for the time being, there is some discussion of sprayfoaming the underside of the flat roof, but then your running into moisture issues.    So right now the thinking is to tear out the plaster and drywall over the lathe, wondering what the best way is to cut a relief cut around the perimeter of the ceiling to minimize damage to the walls?

I had to do something similar a few years back. The walls were in great shape, the ceiling not so much.  At some point the ceiling had been covered with 12x12 interlocking tiles (yuck). I'm sure this was to cover up the nasty paint failure above.  

[attachimg=1]

Check out that awesome ceiling fan... I think the fan on my PC moved more air.

Anyways, I put 1/8" hardboard on the floors and taped the seams to keep the debris from getting underneath.  Then I used a 4-1/2" grinder to cut along the perimeter of the ceiling and went to town breaking the plaster up with a flat shovel.  I had to add several recessed lights so the lath came down as well.  

[attachimg=2]

The whole process was incredibly messy, I don't think dust collection on the grinder would have made much difference.  Just be sure to tape the room off and wear a respirator.

 

[green fever]

Well  guys I have been working with these type of walls & ceilings for years in the uk and I have tried every thing tool wise to help minimise mess and further damage to old ceilings the timber laths never become detatched from the timber joist only plaster that loosens up from either water damage or years of paint and poor repairs , cutting with utility knives works to some degree best results are fein saw and extractor but nails will hurt the blades even the metal cutting type ,  you cant use the wall chaser types with the shrouds and extractors as they get heavy and you cannot adjust the speed only the depth of plunge cut , I have tried large circle cutters designed for downlights the ones that have a full cover but they fill up to fast and man that plaster burns the eyes so glasses a must, I worked on listed buildings here in the uk with national heritage so I know what I am on about ,  and yes I have been underneath ceilings when they come down and they are not like having  sheetrock on your head ,  we screen up and prepare for the worst , most damage caused not by kids jumping on floors above or even water its generally some electrical sub trying to cut lights out ,  that said we try our best , so fein it is .

 

[woodie]

When you say "Fein saw" you don't mean a Multimaster do you?  I've used the Multimaster many times to cut a switch or outlet in but it would've taken an entire day to cut around the perimeter of ceiling.  I can't imagine the number of blades I would have gone through.