Everybody I ask about making my ceilings smooth again tells me to pull them down and put up drywall. So I've stopped asking. (This is not unlike the predictable suggestion to replace my windows.)
Most of my ceilings are generally okay but have that built up debris of a hundred years of paint that didn't always stick. Is there a way to skim coat ceilings so that it will be sure to adhere? Another method?
ETA- I just found this. Am I on the right track?
https://youtu.be/i5mdg4gH1Ko
Skim coat a ceiling?
Re: Skim coat a ceiling?
Are you doing ceiling repairs or trying to smooth out a popcorn/textured ceiling ?
I have had to skim coat sections of ceilings during repairs, including building up areas where the PO had used patches of drywall that were too thick. (I had done some surgery to remove a patch to replace with thinner drywall but then that was an even worse ordeal, and even more labour intensive to correct).
My skimcoated areas have stayed stuck, even over painted areas. I used regular pre-mixed joint compound. There are a couple of areas with a new tiny hairline crack - but there was also a major explosion that shook all the houses in this area (Aug. 16/19), and I noticed the cracks after that.
My $ 0.02: scrape off any seriously loose or flaking areas, before you skim coat. If the plaster is flexible enough to be moved by your hand then shore that up with plaster washers, then mesh tape, and skim coat over that.
See Jane Drill has some great how to videos, including really clear advice about plaster repairs. This might help:
http://seejanedrill.com/plaster-skim-coat/
I have had to skim coat sections of ceilings during repairs, including building up areas where the PO had used patches of drywall that were too thick. (I had done some surgery to remove a patch to replace with thinner drywall but then that was an even worse ordeal, and even more labour intensive to correct).
My skimcoated areas have stayed stuck, even over painted areas. I used regular pre-mixed joint compound. There are a couple of areas with a new tiny hairline crack - but there was also a major explosion that shook all the houses in this area (Aug. 16/19), and I noticed the cracks after that.
My $ 0.02: scrape off any seriously loose or flaking areas, before you skim coat. If the plaster is flexible enough to be moved by your hand then shore that up with plaster washers, then mesh tape, and skim coat over that.
See Jane Drill has some great how to videos, including really clear advice about plaster repairs. This might help:
http://seejanedrill.com/plaster-skim-coat/
Re: Skim coat a ceiling?
Thanks, Willa. I particularly liked the demonstration of the finish coats. Between the two videos, I think I'm getting the hang of it. Most of my ceilings are generally okay, just suffering from age-related cragginess. I've begun to scrape the applied popcorn texture off the living room ceiling and that has exposed a stable surface to the other rooms and one I think I can work with. The large bedroom has a significant crack, so the method shown in the Ask This Old House video may be the way to go. Joint compound (and removing loose material, of course) seems to be the solution to good adhesion.
Re: Skim coat a ceiling?
It's great if you can scrape the popcorn ceiling off before you repair/skim. The Nightmare Apartment had popcorn ceilings. I watched a bunch of videos online about removal, but these ceilings had definitely been painted with several coats of oil paint as no matter what I did, the popcorn crud would not budge. They were real grunge collectors. I did fantasize about adding glitter to them, since I couldn't make them go away (I wasn't going to skimcoat the ceilings in an entire apartment).
One thing they don't do in the "This Old House" video is apply mesh tape over the plaster washers before they skim coat. They DO use large areas of fibreglass screen to stabilize though, which I have not done. The tape or mesh will help to hold onto more joint compound than going over the washers bare. He also seems to not be setting the screws deeply enough with the washers, IME.
I hate dealing with ceilings the most. I think this is a combination of weak upper body strength, but also being a progressive lens wearer. I would typically get terrible neck and shoulder pain after a day of intensive ceiling battle, which I think was exacerbated by having to constantly hold my head a certain way to look through the lower progressive lens area for close-up work. I finally bought different glasses for close work and reading and that helped a lot.
I don't think Tom Da Silva, from This Old House, is a very proficient plasterer. There's lots of good plaster repair and skimcoating videos that show professionals at work, and how they handle their tools. See Jane Drill has a bunch of plaster repair videos, that I found very helpful as her explanations and demonstrations were very clear. She used to teach the trades, so I guess that is why.
One thing they don't do in the "This Old House" video is apply mesh tape over the plaster washers before they skim coat. They DO use large areas of fibreglass screen to stabilize though, which I have not done. The tape or mesh will help to hold onto more joint compound than going over the washers bare. He also seems to not be setting the screws deeply enough with the washers, IME.
I hate dealing with ceilings the most. I think this is a combination of weak upper body strength, but also being a progressive lens wearer. I would typically get terrible neck and shoulder pain after a day of intensive ceiling battle, which I think was exacerbated by having to constantly hold my head a certain way to look through the lower progressive lens area for close-up work. I finally bought different glasses for close work and reading and that helped a lot.
I don't think Tom Da Silva, from This Old House, is a very proficient plasterer. There's lots of good plaster repair and skimcoating videos that show professionals at work, and how they handle their tools. See Jane Drill has a bunch of plaster repair videos, that I found very helpful as her explanations and demonstrations were very clear. She used to teach the trades, so I guess that is why.
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phil
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Re: Skim coat a ceiling?
Ive done both , in one room I stripped all the wallpaper off and washed all the calcimine paint off, taped every crack in the plaster, skim coated to perfection. in other rooms I just applied drywall over the plaster or even removed the plaster.
to fix cracks in plaster I soak the drywall tape in a mix of water and carpenters glue. it sticks better and you can flatten it out, otherwise you need more filler to hide the tape which is the normal way but I hate when it peels so I do this and I've never seen one spot let even try to let go. Ive also not had any of the spiderweb cracks transfer through. you have to fill the space of the thickness of the tape. I do that as a filling operation and I don't put a lot of crown over my tape. If you spread that thickness of a piece of tape plus filler over the entire ceiling it's a lot of mud! drywallers are experts at making those waves between the top of the tape and the adjacent areas not show. you need some mud even over the areas where there is tape to bury it sufficiently. the glossier the paint or if you use solid colors the better job you need to do on the finish or it will show. I think my living room ceiling took about 5 boxes of mud. I did about 5 coats a commercial finisher will do it in less coats because he wont want it to take so long but if you pay for it they can do more coats and achieve greater perfection of course.
it is typical that a year or two after you use drywall and screws even if the finishing is perfect you might see indents near the screws. I can see very slight ones hardly noticible and I could do another go now that it has stabilized more but this is very insignificant. I can barely detect a few of them , nothing popped. dont use nails , they do pop. they are a thing of the past for the most part. screws dont pop. only place I use nails is when I bed the corner bead to keep it flat while it sets.
Ive gotten good at laying it thin and consistently and ridding my mix of bubbles. any bubbles get filled in a second coat. the better you are the less coats you need to do but I do about 5 to reach a situation where my efforts are no longer making a lot of difference.
you will build some stmina. when you hold your hands above your head for long periods you feel some fatigue but by the end of the job it will feel like you are stronger and better at it some of the skills you will develop at first you'll drop more mud as you get better you will do that a lot less because you will learn to control the knife and the consistency much better.
I borrowed a rolling platform it's easier to stand on than a ladder.
when finished, you look up and you have the ceiling flat and painted and no one can tell if it is plaster or drywall. using drywall is half the work but you lose some ceiling height , mine are 9 foot ceilings and the difference of 1/2 inch is not noticeable.
I use corner beads. they help to square up the rounded corners and leave a more finished appearance. it takes the waves out of the corners provides a straight edge for the knife, leaves a more perfect finish.. so I use the corner bead in every corner inside corners as well as outside corners. the outside corners are susceptibel to being knocked inside ones are not.
some just use the drywall tape on inside corners.
with plaster if there are layers of wallpaper especially, I take a drywall knife and knock out the rounded shape then bed my corner bead so it sits flat. maybe you like the look of rounded and imperfect corners as it is typical of plaster. your choice of course. .. you can also get rounded corner beads.
You can use traditional materials all the way which would eliminate the use of drywall tape or mud and instead use only plaster and plaster washers. no screws.. . Personally I don't think it makes the finished job any better at all in fact if you consider the time the drywall will give you a better finish for the same amount of effort. I just wanted mine flat and square and as perfect as I could get so I could put paint that has some sheen. I use the kitchen and bath paint as it is washable and has some sheen. If you dont want to go to the work of really flattening it then you need to use flat paint to hide the imperfections. popcorn was a quick way to avoid all the work of making it perfect but I don't think it is suitable for your house.
If you use mud to flatten the ceiling then mix it really well. add some water to the bucket and mix it with a drill the night before you use it then the bubbles can rise out. there are 4 grades of the stuff I use. never us it straight from the box or bucket, it will be way too stiiff. the more water you add the more drippy it will be and the more it shrinks. as it gives up water it shrinks that's how it works and that's why you can't get there in one coat no matter how good you are.
the taping mud is more yellow because it has more glue. I often add glue to the mud when I am filling holes. I learned some tricks with mixing plaster into the mud to fill larger openings like cracks between sheets.
there is a medium or general purpose and a fine and a finishing mud. the finer stuff has smaller grit. use the fine stuff on the finishing stages. the stuff I use to finish ceilings is called classic finish and I found only certain home depot stored carry it.. I add some glue, about a tablespoon to a fist sized clump for taping but you can't sand it so if you add glue watch for drips after and look after them before it dries. if you want to to add plaster to your mud you can. this will enable you to fill big holes and dips. you can mix the plaster the regular way then mix it with about two or three times as much drywall mud ,, or if you like you can buy gap filling compound. once you start the reaction with the plaster you have to use it up and clean your tools. if you fill a big dent with drywall mud it will shrink and crack and take forever to dry otherwise.
when you apply it put a bead about an inch around along the front edge of the drywall knife. press it against the ceiling and pull back to deposit it , do that three times to make a good deposit of the mud on the ceiling.
then do the same again only a smaller bead, push up pull back and you can pull a smooth stroke as long as your reach. you will then be collecting more mud than you rare depositing , return it to your tray and keep going. move to the right and overlap your strokes slightly. you will leave some squeeze out which you can knock off when it's dry with a pole sander. the more you do and the smoother you want it the more work it is. as you go you will get better at pulling it down ( or up? ) smoothly without bubbles. to avoid bubbles mix it really well. as you get to the bottom of your tray you will find the material is a bit coarse, you can afford to chuck the last fist full to get more clean stuff. what happens is the action of applying it filers the stuff and you are left with coarse stuff with less glue in it.
I add water as I go the consistency is very important. first mistake people make is trying to use it when it isn't fluid enough to spread easily.
now if you do the same with plaster , you can the thing with plaster is that you have working time from when you mix until you use it up and if you are not fast enough you have to chuck it and go again. If you have someone to mix plaster and pass it to you that could speed things up a lot.
my opinion is that either way you are trying to achieve a nice flat perfect surface and the materials you use will not be visible through the paint. I dont' see enough reason not to use modern materials but of course I do respect that some want that to achieve that degree of originality. you should make that decision yourself.
if you use drywall you can get 5/8th fireproof, use that if the wall or ceiling will ever divide a suite for fire protection. if you use 1/2 you can choose from normal or lightweight. the sheets are lighter. you can use the expensive soundproof stuff but it is super heavy so Id just use that on walls if sound proofing is an issue. I used that to block traffic noise. it was expensive but it blocks about 7 times the sound as regular drywall for it's thickness. if the ceiling is already pretty flat but there is debris like popcorn or wallpaper you can use the 1/4" stuff. you can tape and fill just like you put fresh drywall up and the thickness will be less. I would not use the 1/4 on its own but if you laminate it over plaster its fine you can screw anywhere and at least hit the lath.
if you chose to refinish the plaster you might want o give it a coat of good oil based paint to get a good surface to bond to on the plaster and to block out any calcimeine if you have that , I did.
I used a small drill to locate the studs. it left a row of tiny holes and once you find the first stud ( or joist) the others follow suit. if the bit goes through after about an inch then you missed, if you hit wood you can't push the bit after drilling in 1 inch you only need a tiny bit maybe 1/16th or so. when I locate both sides of the joist then I make a center mark and transfer that mark to the wall so you dont loose the location. you can do this as a first step so you can always find their exact location.
If you use drywall mud and drop that in your eye, you will live. yea you should wear goggles right , but If you use plaster YES definitely wear goggles for sure. You dont want an eye full of plaster !
if you use plaster be aware that you could have issues with paint sticking to it. the reason that water soluble calcimine paint was used was because the plaster could reject the paint, now maybe with modern paint that is not an issue? If you use latex paint that is another material that is non original. where do you stop? your decisions.. you can use colored plaster , that's nice.
my take after doing a lot of it is that you need to really think of the final objective and plan towards that. use the materials you want to , experiment. I stripped one room and felt it was not worth the extra effort to not use modern materials. by the time I had all the paper off it was covered with calcimine paint then after I got rid of that it had a lot of tiny spiderweb cracks. and taping every one was a crazy chore.. It worked.. honestly 1/4 inch drywall is the way I'd go and leave the rough stuff and any wallpaper where it is. it helps hold it together if you don't remove it and it saves time because it will level things out for you and provide a good new surface to work on. the cost of materials is minimal either way. the 1/4 inch stuff is easy to lift by yourself without a special lifter or a helper, just some support sticks is enough. just dont use that 1/4 inch stuff on it's own, its not for that.
if you are aiming for perfection just try to get it as close as you can then primer it. then do more finishing and primer again. this will help as it then stops sucking drywall up into the new mix and you can see better where you have done previously you will see the flatness better because it has more sheen and the drywall mud is stronger if you have some primer between coats it all bonds together. the room will feel less "gritty " once you seal it in. drywall is meanto be sealed with paint of course. If you use plaster and also paint between Im not sure if that is good, others have dome more of the traditional plaster work and might add more on that. you might strip enough to see if you wil be wahing off the calimine paint , when it gets wet it lets go, it isn't like latex paint.
plaster in itself will not really dissolve because it gets wet. wet ceilings aren't usually a problem anyway bit there is some obvious difference between the products although they can play together. don't be afraid to really wet the plaster walls as you are stripping them. a wet mop might help with the popcorn once you scrape most of that mess off. the popcorn was a 70's thing..
now one little warning. MUD used in the 70's is likely to contain asbestos. although your ceiling is plaster and not likely asbestos, you may be dealing with a layer of asbestos material that was applied when the mud contained asbestos It cost me $50 to do a test. probably worth it as you make decisions on your favorite process. if you need to mask up through the whole job or take further measures, it might affect your decision to cover it in or play with that stuff. from what I found the drywall didn't usually contain the asbestos the danger is that the mud did and it may be on top of your plaster if you have popcorn because it's probably in that era.
to fix cracks in plaster I soak the drywall tape in a mix of water and carpenters glue. it sticks better and you can flatten it out, otherwise you need more filler to hide the tape which is the normal way but I hate when it peels so I do this and I've never seen one spot let even try to let go. Ive also not had any of the spiderweb cracks transfer through. you have to fill the space of the thickness of the tape. I do that as a filling operation and I don't put a lot of crown over my tape. If you spread that thickness of a piece of tape plus filler over the entire ceiling it's a lot of mud! drywallers are experts at making those waves between the top of the tape and the adjacent areas not show. you need some mud even over the areas where there is tape to bury it sufficiently. the glossier the paint or if you use solid colors the better job you need to do on the finish or it will show. I think my living room ceiling took about 5 boxes of mud. I did about 5 coats a commercial finisher will do it in less coats because he wont want it to take so long but if you pay for it they can do more coats and achieve greater perfection of course.
it is typical that a year or two after you use drywall and screws even if the finishing is perfect you might see indents near the screws. I can see very slight ones hardly noticible and I could do another go now that it has stabilized more but this is very insignificant. I can barely detect a few of them , nothing popped. dont use nails , they do pop. they are a thing of the past for the most part. screws dont pop. only place I use nails is when I bed the corner bead to keep it flat while it sets.
Ive gotten good at laying it thin and consistently and ridding my mix of bubbles. any bubbles get filled in a second coat. the better you are the less coats you need to do but I do about 5 to reach a situation where my efforts are no longer making a lot of difference.
you will build some stmina. when you hold your hands above your head for long periods you feel some fatigue but by the end of the job it will feel like you are stronger and better at it some of the skills you will develop at first you'll drop more mud as you get better you will do that a lot less because you will learn to control the knife and the consistency much better.
I borrowed a rolling platform it's easier to stand on than a ladder.
when finished, you look up and you have the ceiling flat and painted and no one can tell if it is plaster or drywall. using drywall is half the work but you lose some ceiling height , mine are 9 foot ceilings and the difference of 1/2 inch is not noticeable.
I use corner beads. they help to square up the rounded corners and leave a more finished appearance. it takes the waves out of the corners provides a straight edge for the knife, leaves a more perfect finish.. so I use the corner bead in every corner inside corners as well as outside corners. the outside corners are susceptibel to being knocked inside ones are not.
some just use the drywall tape on inside corners.
with plaster if there are layers of wallpaper especially, I take a drywall knife and knock out the rounded shape then bed my corner bead so it sits flat. maybe you like the look of rounded and imperfect corners as it is typical of plaster. your choice of course. .. you can also get rounded corner beads.
You can use traditional materials all the way which would eliminate the use of drywall tape or mud and instead use only plaster and plaster washers. no screws.. . Personally I don't think it makes the finished job any better at all in fact if you consider the time the drywall will give you a better finish for the same amount of effort. I just wanted mine flat and square and as perfect as I could get so I could put paint that has some sheen. I use the kitchen and bath paint as it is washable and has some sheen. If you dont want to go to the work of really flattening it then you need to use flat paint to hide the imperfections. popcorn was a quick way to avoid all the work of making it perfect but I don't think it is suitable for your house.
If you use mud to flatten the ceiling then mix it really well. add some water to the bucket and mix it with a drill the night before you use it then the bubbles can rise out. there are 4 grades of the stuff I use. never us it straight from the box or bucket, it will be way too stiiff. the more water you add the more drippy it will be and the more it shrinks. as it gives up water it shrinks that's how it works and that's why you can't get there in one coat no matter how good you are.
the taping mud is more yellow because it has more glue. I often add glue to the mud when I am filling holes. I learned some tricks with mixing plaster into the mud to fill larger openings like cracks between sheets.
there is a medium or general purpose and a fine and a finishing mud. the finer stuff has smaller grit. use the fine stuff on the finishing stages. the stuff I use to finish ceilings is called classic finish and I found only certain home depot stored carry it.. I add some glue, about a tablespoon to a fist sized clump for taping but you can't sand it so if you add glue watch for drips after and look after them before it dries. if you want to to add plaster to your mud you can. this will enable you to fill big holes and dips. you can mix the plaster the regular way then mix it with about two or three times as much drywall mud ,, or if you like you can buy gap filling compound. once you start the reaction with the plaster you have to use it up and clean your tools. if you fill a big dent with drywall mud it will shrink and crack and take forever to dry otherwise.
when you apply it put a bead about an inch around along the front edge of the drywall knife. press it against the ceiling and pull back to deposit it , do that three times to make a good deposit of the mud on the ceiling.
then do the same again only a smaller bead, push up pull back and you can pull a smooth stroke as long as your reach. you will then be collecting more mud than you rare depositing , return it to your tray and keep going. move to the right and overlap your strokes slightly. you will leave some squeeze out which you can knock off when it's dry with a pole sander. the more you do and the smoother you want it the more work it is. as you go you will get better at pulling it down ( or up? ) smoothly without bubbles. to avoid bubbles mix it really well. as you get to the bottom of your tray you will find the material is a bit coarse, you can afford to chuck the last fist full to get more clean stuff. what happens is the action of applying it filers the stuff and you are left with coarse stuff with less glue in it.
I add water as I go the consistency is very important. first mistake people make is trying to use it when it isn't fluid enough to spread easily.
now if you do the same with plaster , you can the thing with plaster is that you have working time from when you mix until you use it up and if you are not fast enough you have to chuck it and go again. If you have someone to mix plaster and pass it to you that could speed things up a lot.
my opinion is that either way you are trying to achieve a nice flat perfect surface and the materials you use will not be visible through the paint. I dont' see enough reason not to use modern materials but of course I do respect that some want that to achieve that degree of originality. you should make that decision yourself.
if you use drywall you can get 5/8th fireproof, use that if the wall or ceiling will ever divide a suite for fire protection. if you use 1/2 you can choose from normal or lightweight. the sheets are lighter. you can use the expensive soundproof stuff but it is super heavy so Id just use that on walls if sound proofing is an issue. I used that to block traffic noise. it was expensive but it blocks about 7 times the sound as regular drywall for it's thickness. if the ceiling is already pretty flat but there is debris like popcorn or wallpaper you can use the 1/4" stuff. you can tape and fill just like you put fresh drywall up and the thickness will be less. I would not use the 1/4 on its own but if you laminate it over plaster its fine you can screw anywhere and at least hit the lath.
if you chose to refinish the plaster you might want o give it a coat of good oil based paint to get a good surface to bond to on the plaster and to block out any calcimeine if you have that , I did.
I used a small drill to locate the studs. it left a row of tiny holes and once you find the first stud ( or joist) the others follow suit. if the bit goes through after about an inch then you missed, if you hit wood you can't push the bit after drilling in 1 inch you only need a tiny bit maybe 1/16th or so. when I locate both sides of the joist then I make a center mark and transfer that mark to the wall so you dont loose the location. you can do this as a first step so you can always find their exact location.
If you use drywall mud and drop that in your eye, you will live. yea you should wear goggles right , but If you use plaster YES definitely wear goggles for sure. You dont want an eye full of plaster !
if you use plaster be aware that you could have issues with paint sticking to it. the reason that water soluble calcimine paint was used was because the plaster could reject the paint, now maybe with modern paint that is not an issue? If you use latex paint that is another material that is non original. where do you stop? your decisions.. you can use colored plaster , that's nice.
my take after doing a lot of it is that you need to really think of the final objective and plan towards that. use the materials you want to , experiment. I stripped one room and felt it was not worth the extra effort to not use modern materials. by the time I had all the paper off it was covered with calcimine paint then after I got rid of that it had a lot of tiny spiderweb cracks. and taping every one was a crazy chore.. It worked.. honestly 1/4 inch drywall is the way I'd go and leave the rough stuff and any wallpaper where it is. it helps hold it together if you don't remove it and it saves time because it will level things out for you and provide a good new surface to work on. the cost of materials is minimal either way. the 1/4 inch stuff is easy to lift by yourself without a special lifter or a helper, just some support sticks is enough. just dont use that 1/4 inch stuff on it's own, its not for that.
if you are aiming for perfection just try to get it as close as you can then primer it. then do more finishing and primer again. this will help as it then stops sucking drywall up into the new mix and you can see better where you have done previously you will see the flatness better because it has more sheen and the drywall mud is stronger if you have some primer between coats it all bonds together. the room will feel less "gritty " once you seal it in. drywall is meanto be sealed with paint of course. If you use plaster and also paint between Im not sure if that is good, others have dome more of the traditional plaster work and might add more on that. you might strip enough to see if you wil be wahing off the calimine paint , when it gets wet it lets go, it isn't like latex paint.
plaster in itself will not really dissolve because it gets wet. wet ceilings aren't usually a problem anyway bit there is some obvious difference between the products although they can play together. don't be afraid to really wet the plaster walls as you are stripping them. a wet mop might help with the popcorn once you scrape most of that mess off. the popcorn was a 70's thing..
now one little warning. MUD used in the 70's is likely to contain asbestos. although your ceiling is plaster and not likely asbestos, you may be dealing with a layer of asbestos material that was applied when the mud contained asbestos It cost me $50 to do a test. probably worth it as you make decisions on your favorite process. if you need to mask up through the whole job or take further measures, it might affect your decision to cover it in or play with that stuff. from what I found the drywall didn't usually contain the asbestos the danger is that the mud did and it may be on top of your plaster if you have popcorn because it's probably in that era.
Re: Skim coat a ceiling?
Willa wrote:I hate dealing with ceilings the most.
I hear you. I have a temperamental neck and sometimes find it difficult to get into a position where I can focus more on the work I'm doing than the discomfort. I think, as Phil says, you build up stamina pretty quickly but getting started can be awkward. As far as technique, I'm not expecting perfection from the YouTube videos; just the distilled knowledge of watching several to see how other people do the job. It's not a bad idea to look at the comments and see if the consensus is approval or disapproval of the method.
Phil, thank you for the pointers. I have a limit to how deeply I want to get into this project, based on my skills, time and resources. Facing the old plaster with drywall is out. I don't see myself removing all the trim in the room and then throwing off the alignment of the trim at the front door... I'd rather just live with the imperfections. I don't mind the grainy texture of old plaster but would like it to be reasonably consistent.
My "devil's advocate" friend did a good job of making me nervous about how well a skim coat will adhere to the ceiling or walls. He conjured an image of a filthy chunk of plaster splashing into my Negroni a couple of years down the pike. I'll prepare the surfaces according to the best recommendations. For starters, they'll get a good scrubbing with TSP. Should I do more than that? Is it advisable to score the old plaster in some way to help adhesion?
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mjt
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Re: Skim coat a ceiling?
I haven't scored the plaster when I've done this. Everything is still adhering, even when I've used pre-mixed joint compound. There have been some areas where I've used setting-type compounds and those are fine too. I'd expect them to perhaps adhere better, though you have less time to work with them to get them smooth. They are also harder, so take more sanding if you don't get them smooth from the start.
Re: Skim coat a ceiling?
Manalto wrote:
My "devil's advocate" friend did a good job of making me nervous about how well a skim coat will adhere to the ceiling or walls. He conjured an image of a filthy chunk of plaster splashing into my Negroni a couple of years down the pike. I'll prepare the surfaces according to the best recommendations. For starters, they'll get a good scrubbing with TSP. Should I do more than that? Is it advisable to score the old plaster in some way to help adhesion?
Geez with any of those "devil's advocate" types. Ask your pal what personal experience they have with doing this sort of repair ?
From living in a succession of fixer upper type places that had repaired ceilings and walls (by me or my ex) I had 0% chunks or even grains of plaster fall off the ceiling or walls. This house has the worst plaster of them all, and in the last 18 months also was in proximity to major road repairs with lots of vibration, heavy gravel trucks coming down my street, increased traffic due to detours, etc. A few hairline cracks developed, but that has been it.
I have never washed down a wall that needed plaster repairs, with the except of the bathroom which had major wall issues due to the calcimine paint on the bottom layer. You'll know calcimine paint by the way you can rub it off the wall. It coats your hand like chalk on a chalkboard. This probably needs to get scrubbed off, unless you will be skim coating 100% of that surface. I scrubbed 95% off and did not have any adhesion issues. I have also never scored a wall or ceiling either.
There are adhesives in joint compound that help it to adhere. Joint compound is different from lime plaster - which is a different chemistry, with different issues. I wouldn't bother with lime plaster as it needs an extremely long time to cure before it can be painted. It is the material for historically correct repairs - like an earlier 1800's house.
My goal with repairs has always been "good enough". By this I mean that the repaired surface becomes unremarkable, with no obvious demarcation from new to old. I can often look backwards, and see that I "could have" kept going, and built up even more layers to make everything even smoother - but to what end ? There's a point where the misery has to end, and the room needs to be finished. Several mm more of skim coating and smoothing will not make the room more functional, and the smoothness of the ceiling as viewed from the floor below is significantly different than being a few inches away from it, with a harsh light that exposes all the flaws.
My repairs created a smooth finish, but due to all the settling and previous wear and tear in this house, my walls will never be truly flat, and I am completely fine with that ! Flat or eggshell finish paints are your friend, too.
Here's photos of the worst ceiling in the house, the one with !9! drywall patches that were too thick, partially scraped off wallpaper on the surface, loose plaster and assorted other troubles:
- _DSC0007.jpg (883.27 KiB) Viewed 6652 times
Here's that room in progress. You can see there were lots of troubles:
- _DSC0006.jpg (1.28 MiB) Viewed 6652 times
Here's that same room, "good enough" :
- _DSC0020.jpg (876.74 KiB) Viewed 6652 times
If you got up on a ladder to examine the ceiling there's some small areas that could have been a little more built up, or sanded more, or whatever - but it is better than where it started, and the room just feels like a room again.
I mean, maybe don't invite that Devil's Advocate over, and lend them a headlamp, a magnifying glass and a ladder to give their $ 0.02 on your repairs. If they are too scared of your ceiling repairs, make them take you to a pub and buy you a couple of drinks there. On their dollar of course.
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phil
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Re: Skim coat a ceiling?
with walls , if you laminate you do have the difference in height to contend with. In mine I took out the plaster and put insulation and drywall to achieve the same height because that would bug me. on ceilings thare was no issue. I had a non original crown molding but I chucked it.
You could consider a tin ceiling and avoid the pain? i like the idea of painting them and then putting them up. I like doing it myself, I find it quite therapeutic but the trick is to separate your living space so you aren't living in the drywall dust, just working in it. a plastic divider might be enough to give that separation of work and living space.
probably part of it is that it is hard to hold your hands above your heart for extended periods, so you have to stop and do a jiggle dance as you go ..
you'll build strength in a week or so doing it an hour or two a day. Just dont push yourself.
pole sanding can be awkward too. I find it often easier to get myself right up near the ceiling and sand in circles using a foam pad thing. I sense the hollows as much by feel as by sight. that way I turn my eyes away from the work a lot. I only sand once per coat and I don't use sandpaper to level it, only to knock the bumps and pips off. with wood sand with the grain drywall doesn't have grain and you don't want to see sanding lines , I was taught that if you go in circles the sanding marks dissapear. i sort of sand with the block above my right shoulder and maybe switch hands now and then.
I have the lock feature on my cell phone that reads a fingerprint. I found it impossible to use it because I removed my fingerprints ! so during the job I had to punch in the unlock code. gloves just give me sweaty hands.
the first coats you apply more, and hold the knife more flat to the surface, later when you are just filling hollows you can hold the knife more perpendicular so the knife is sort of scraping it on rather than laying it on if that makes any sense. filling little holes and bubbles is really easy. the finer the finish the more wet you can make the mud since you are putting it on a bit differently. the finer finishing mud is better for that.
I like to do rows as ling as my reach and move sideways , then turn and do the same at 90 degrees.. so mostly I do pull strokes. you might find that some pros throw it on doing more of a semi random arc pattern, whatever works I guess.
if you put too much water in your mud you have to add more drywall compound so try not to add too much. You can't take the water back out easily. I often dip my knife in a bucket as I go to add water to the mix. you'll find the consistency you like by experimenting.
watching lots of videos will help. this one shows how to mix your mud with plaster for filling deeper holes, so they dry fast without a lot of shrinkage. yoiu can put that stuff on thick and it will still harden up. sometimes I mix in glue like if I think it could break from being bumped.
I bed the tape and corner bead with a bit of glue in the mud..it really makes it hard and stable similar to plaster. a gallon of carpenters glue is only about 15 bucks or so and that goes a long way so it isn't expensive. I tried an experiment where i had an electrical box hole in an interior wall that I was covering with the baseboard anyway and just crumpled up some paper filled the hole with plaster, It hardened up and worked well , in that case I was just filling a void that was not going to ever be seen but it demonstrated to me that I can put plaster super thick if it were drywall mud it would not work as it would be way too much in one spot to ever dry right..
https://www.youtube.com/watch?v=sp-RatKtLYU
you can also scrape with a knife a bit.
I'd find a straightedge and check visually first, see how flat it really is before you start. you can hide lots with dull paint and maybe you dont want it flat.. in my place the walls were all pretty well dead flat as plaster so it didn't make much visual difference but some have different plaster. If the keys are breaking you need to stabilize it. laminating over top is easiest because then that holds the plaster issues in place, but you can do it with plaster washers, epoxy etc. i f the surface has big waves that run for feet that is a bit harder to fix but its just about perseverance to achieve the finish level you want to achieve. they make really wide blades. I bought one but just found it awkward to handle myself.
I used Kilz or something similar on top of my plaster after I removed any wallpaper and hot mopped for hours to get the calcimine off, but I didn't skim coat with plaster , I used mud.
if you try and dont reach the level you want then you can always paint and it can always be done again later. the layer of paint won't stop more work in the future. It's nice if you can clear the room of any obstacles. hiring a pro might help especially if they dont mind teaching you and letting you do some of it. Those guys can do in a day what a homeowner does in a week. some like the platter some use a tray. I like the cheap plastic trays because I can put it down and it doesn't run all over if it is thin. a lot of the pros use the platter thing.. your preference.
I dont think the argument about weather plaster is better or drywall is healthy we all respect the originality and realize that your methods should be your choice and you can find the ways you like and your investment , your choice. If you want to restore it like a museum and use only traditional tools and materials, most of us admire that.
You could consider a tin ceiling and avoid the pain? i like the idea of painting them and then putting them up. I like doing it myself, I find it quite therapeutic but the trick is to separate your living space so you aren't living in the drywall dust, just working in it. a plastic divider might be enough to give that separation of work and living space.
probably part of it is that it is hard to hold your hands above your heart for extended periods, so you have to stop and do a jiggle dance as you go ..
you'll build strength in a week or so doing it an hour or two a day. Just dont push yourself. pole sanding can be awkward too. I find it often easier to get myself right up near the ceiling and sand in circles using a foam pad thing. I sense the hollows as much by feel as by sight. that way I turn my eyes away from the work a lot. I only sand once per coat and I don't use sandpaper to level it, only to knock the bumps and pips off. with wood sand with the grain drywall doesn't have grain and you don't want to see sanding lines , I was taught that if you go in circles the sanding marks dissapear. i sort of sand with the block above my right shoulder and maybe switch hands now and then.
I have the lock feature on my cell phone that reads a fingerprint. I found it impossible to use it because I removed my fingerprints !
so during the job I had to punch in the unlock code. gloves just give me sweaty hands. the first coats you apply more, and hold the knife more flat to the surface, later when you are just filling hollows you can hold the knife more perpendicular so the knife is sort of scraping it on rather than laying it on if that makes any sense. filling little holes and bubbles is really easy. the finer the finish the more wet you can make the mud since you are putting it on a bit differently. the finer finishing mud is better for that.
I like to do rows as ling as my reach and move sideways , then turn and do the same at 90 degrees.. so mostly I do pull strokes. you might find that some pros throw it on doing more of a semi random arc pattern, whatever works I guess.
if you put too much water in your mud you have to add more drywall compound so try not to add too much. You can't take the water back out easily. I often dip my knife in a bucket as I go to add water to the mix. you'll find the consistency you like by experimenting.
watching lots of videos will help. this one shows how to mix your mud with plaster for filling deeper holes, so they dry fast without a lot of shrinkage. yoiu can put that stuff on thick and it will still harden up. sometimes I mix in glue like if I think it could break from being bumped.
I bed the tape and corner bead with a bit of glue in the mud..it really makes it hard and stable similar to plaster. a gallon of carpenters glue is only about 15 bucks or so and that goes a long way so it isn't expensive. I tried an experiment where i had an electrical box hole in an interior wall that I was covering with the baseboard anyway and just crumpled up some paper filled the hole with plaster, It hardened up and worked well , in that case I was just filling a void that was not going to ever be seen but it demonstrated to me that I can put plaster super thick if it were drywall mud it would not work as it would be way too much in one spot to ever dry right..
https://www.youtube.com/watch?v=sp-RatKtLYU
you can also scrape with a knife a bit.
I'd find a straightedge and check visually first, see how flat it really is before you start. you can hide lots with dull paint and maybe you dont want it flat.. in my place the walls were all pretty well dead flat as plaster so it didn't make much visual difference but some have different plaster. If the keys are breaking you need to stabilize it. laminating over top is easiest because then that holds the plaster issues in place, but you can do it with plaster washers, epoxy etc. i f the surface has big waves that run for feet that is a bit harder to fix but its just about perseverance to achieve the finish level you want to achieve. they make really wide blades. I bought one but just found it awkward to handle myself.
I used Kilz or something similar on top of my plaster after I removed any wallpaper and hot mopped for hours to get the calcimine off, but I didn't skim coat with plaster , I used mud.
if you try and dont reach the level you want then you can always paint and it can always be done again later. the layer of paint won't stop more work in the future. It's nice if you can clear the room of any obstacles. hiring a pro might help especially if they dont mind teaching you and letting you do some of it. Those guys can do in a day what a homeowner does in a week. some like the platter some use a tray. I like the cheap plastic trays because I can put it down and it doesn't run all over if it is thin. a lot of the pros use the platter thing.. your preference.
I dont think the argument about weather plaster is better or drywall is healthy we all respect the originality and realize that your methods should be your choice and you can find the ways you like and your investment , your choice. If you want to restore it like a museum and use only traditional tools and materials, most of us admire that.
Re: Skim coat a ceiling?
Phil, your answers are always amazing. I just can't type that much. Sometimes I wonder why I didn't take Miss Slocum's typing class in 7th and 8th grade, oh well, next life. I'll throw my hat in the ring for answers, scrape the surface as best as you can, then secure the plaster with plaster washers. I like watered down white glue as a bonding agent. I fiber tape the cracks and paper tape the corners. I like the first coat with Durabond 90 and then use easy sand Duraond 45 after that. My work comes out nice and smooth using this method.You can hand sand it using a strong light to catch and ripplesin the wall/ceiling.