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The Old House
zenpotter

Repairing holes in plaster from plumbing repair work.

zenpotter
17 anni fa

We just had to have an extensive plumbing repair job. The PO put in a bathroom on the second floor that was put in with many problems we have had to have it totally re-plumbed.

Now we have plaster and lath walls to repair. Along with ceilings that appear to be a fiberboard covered with a thin layer of plaster. The walls are 3/4" thick the ceiling 1"

The largest hole in a wall goes from a corner out 58" and down from the ceiling for 78". The same room has a ceiling hole that is just about 4' x 4'. One side meets the wall a second side is 6"out from the wall. All of the cuts are very rough.

The rest of the rooms aren't quite as bad. We have had suggests for repair work done with sheet rock and with plaster. None of them sound like the best way to do it, whatever that may be. The advice all came from people that have never done the same kind of work themselves.

So, we are looking for help. We want to do it ourselves 1. because we like to work on the house 2. we just spent and arm and a leg for the plumbing work.

The link I am adding is to the same question on a different site since I couldn't add the photo here.

Here is a link that might be useful: photo of one room

Commenti (12)

  • ginam_oh
    17 anni fa
    Ultima modifica: 9 anni fa

    I did extensive plaster work in our bathroom in the spring, and while it was labor- and time-intensive, it was well worth it. I made my own lime putty, aged it, mixed my own plaster, and applied it. I cut/pasted my blog entries regarding this below. Hope it will be of some help to you.
    Long post, I realize.... Gina

    Monday, May 15
    I bought Type S Hydrated Lime at my local masonry builders' supply. Since this was my first time making lime putty I really wanted to go with a true quicklime or similar product, but the Type S was available, and from what I'd read it seemed as though it'd work. (note: finding plaster recipes is really hard, but if you look for fresco plaster you'll have much better luck, at least I did). So I took a 5-gallon bucket, filled it about a third of the way with water, then began adding lime and stirring until it was all well mixed. I continued to add lime and to mix well until my putty had the consistency of a thick yogurt. Then I covered the whole shebang with about an inch of water so the lime wouldn't begin to carbonate, and let it sit for a while. Funny thing about lime putty, it's actually better the longer it gets to sit, but I didn't have time to wait too long. My next batch of plaster will have great putty because I mixed it all at once and what I didn't use in our bathroom is happily sitting in 5-gallon buckets, covered with water, continuing to slake and get completely hydrated.

    Getting good, sharp sand was not easy either. I ended up using general-purpose medium builders sand. Probably a little coarser than what I really needed, but so far (knocking on wood) it's holding up. I did NOT use any gypsum ("gauging plaster") because it does not hold up well in a moist environment, and let's face it: a bathroom is quite a moist environment. So we went lime, sand, hair only.

    Mixing the plaster went as follows:
    Slop out some lime putty (keep track by volume of what you're using) into a mixing tub

    Add sand: I found my recipe in a 1920s era encyclopedia. They suggested using a mix of one part putty to three parts sand for "coarse stuff," one part putty to three parts sand for the second coat, and putty alone or one part putty to one part fine sharp sand for the skim coat.

    "Knock it up" by mixing, beating, mixing, beating, mixing again and it will become more and more plasticized

    Add the hair. The amount of hair is kind of a judgement call, especially since I was not making much plaster. I added and mixed until it seemed like things were fairly "hairy" and then put some on a trowel and hit it sharply against my bucket. I ended up with about a 5-inch glob of plaster with lots of hairs visible hanging down. A fabulous, fabulous session at the Traditional Building Conference taught me that little rule of thumb...er, hair. My old encyclopedia notes that the second coat can be mixed minus the hair or with the hair in halved amounts, and straight putty or one part putty to one part sand for the final coat.

    After I had what I thought was a reasonable mix, and after thoroughly wetting everything and spraying with a bonding agent, I started troweling it onto the walls. I have no shame when I say it's HARD to get plaster nice and even. HARD. Luckily, since this is the bathroom (which is the experimental room anyway and will be changed extensively at some point), I did not worry too very much. Figured if it stuck to each other and to the walls, we could sand down where necessary and make it all shake out.

    All my plaster notes made mention of slopping the plaster on, then letting it sit for some time before "working it up" with a wooden or plastic float. This "working up" is apparently not my strong suit. The first time I tried it, a lot of my plaster stuck to the float. Uh-oh. Must have not let it set up long enough. The second time I tried, maybe things had been allowed to set for too long, because it didn't really feel as though I was doing anything. Time will tell, and I'm sure I'll get better at it with each new project. After all, plasterers used to apprentice for months, even years, before they were allowed to do any plasterwork in a visible location!

    Tuesday, June 13, 2006
    Well whaddaya know--the encyclopedia was right!
    The recipe I used for plaster came from an old encyclopedia, which also mentioned the after-care of plaster. This included misting (did that) and scouring with a wood float. When I first tried to scour the plaster, it was not quite cured enough, and some of it stuck to the wood float and came off. This, obviously, was not the intended result, so I stopped. But I did mist. Scouts' honor!

    Now my beloved skim coat that took so long is cracking here and there, despite the misting. I figured I had nothing to lose by trying to scour it with the wood float since it has cured for a couple of days now. With more than a little trepidation, I took said float in hand, wet it down, and began scrubbing my sweet, innocent plaster wall in a circular motion. Hard. Holy moley! Everything kind of evened out, the cracks disappeared (with a few exceptions . . . feel my pain below), and my wobbly uneven skim coat began to look like REAL plaster that had been done by someone who knew what he/she was doing. Do you believe in miracles? Yes!

    Now, the problem. There are a few small areas of the wall on which the scouring did not work. In fact, on these areas, large chunks of skim coat began to fall off the wall as I scoured. Not cool. Not cool at all. And I have no idea what made the difference from one area to the next. What the heck?

    ?????????

    Soooo, it looks like I have a bit of patching to do. I'm not looking forward to that, especially after all the mini anxiety attacks this danged wall has already given me. Looks like I've got a lot more experimenting to do as well. Thank goodness the bathroom walls are nearly always covered with a shower curtain and are only visible to V, me, and, once I post pictures, all my friends in cyberland!

    Wednesday, June 14
    For Greg (Petch House), who responded to my last post about using the wood float. I was a real nonbeliever at first. I mean, who seriously would think that going back to the plaster (the plaster you labored so hard at to just get to stay on the danged wall) and ripping back over it with a piece of wood could somehow magically make it smooth and crack-free? But somehow it does work. My old-timey plastering guide notes that scouring with the wood float is a necessary step on the process because it "gets the fat back." While I'm not hip to my 1920s-era plastering terminology, I think what it boils down to is this. The skim coat is made of lime putty and sand. Steel finishing trowels have a tendency to (I don't know how or why) separate the two and cause a less-than-strong finished product. The source I have says to go over it once with the steel trowel, just to get it to a modicum of smoothness, then leave it alone. I had a verrrrry difficult time trusting in this logic. After all, wasn't I striving for that beautiful, smooth, clean plaster wall? But by gosh, it actually worked. I put up the skim coat, troweled it over once, and left it.

    "Getting the fat back" refers to the wood float's magical ability to push the lime and sand back together and compress the whole shebang into a lovely skim coat. Before I used the float, my walls looked....well, kind of sandy/plastery, not like smooth plaster should look. But the areas in which I used the float, my walls looked super smooth after I was finished. One note of warning: scouring with the wood float is a killer on the wrists! You have to try to maintain an even pressure, all the while scrubbing in circles, but also trying to not create any suction between the float and the plaster (I believe this was my downfall in the lost plaster fiasco....however, I don't want to try it again in order to prove it).

    Apparently people who have oodles more experience than me with plaster can actually "polish" a wall to practically a mirror finish using a float. I don't envision that being in my repertoire anytime soon, although I'd sure like to try my hand at it. Virginia Limeworks has a finish that they use in bathroom environments that actually looks almost like a perfect white piece of marble, minus the graining and feathering. It's that smooth and shiny. In person, it's absolutely drop-dead gorgeous. When I had the good fortune to spend a day with Jimmy Price and the VL gang last summer (part of Travis McDonald's Poplar Forest program, which totally rocked!), I practically had to be dragged from their demonstration rooms. I kept stroking this lovely, shiny, smooth, polished surface. It was amazing. Incidentally, if you're ever in the Lynchburg area and are into lime, plaster, and/or museum-quality restoration work, I highly, highly, highly recommend visiting Poplar Forest and giving the guys at VA Limeworks a call. Both experiences are fantabulous. :)

    Here is a link that might be useful: My blog

  • zenpotter
    Autore originale
    17 anni fa
    Ultima modifica: 9 anni fa

    That is a long post, thank you.

    I have some questions after a quick read.

    1. Why the hair? Is it necessary?
    2. Did you have to re-place lath or did you use screen?
    3. How large of an area did you do at once?

  • ericwi
    17 anni fa
    Ultima modifica: 9 anni fa

    Zenpotter, I would never try to discourage you from repairing your bathroom walls with authentic lime putty, reinforced with horsehair, and smoothed out with a wooden float. My understanding is that 100 per cent lime putty takes about one year to fully cure. Regardless of what type of finish is applied, it will be necessary to fasten some sort of lath, such as wood lath, or wire lath, or rocklath, to the structure of the house. This is generally done with nails. You might have to actually remove more of the original plaster, in some places, to get good access to a wooden beam or stud, in order to securely attach the lath as needed. If you decide to use sheetrock as your backing for finish plaster, then it will be necessary to coat the sheetrock with an adhesive, after it is installed, but before the finish coat plaster is applied. However, if wood lath or wire lath is chosen, then you can apply a modern base coat plaster, pre-mixed. The pre-mix base coat will very likely contain chopped fiberglass to improve its strength, instead of horsehair. Since chopped fiberglass is not so good to breath, you should use come care when mixing this with water, to avoid raising a cloud of dust. Base coat plaster will set up in less than an hour, and can be coated with finish plaster the same day, if necessary. There is no great skill involved in application of base coat plaster. You have to mix it with reasonable care, and press it in place with sufficient force that it penetrates the lath, and binds firmly to the wall or ceiling. It needs to be troweled reasonably flat, and should be slightly below the intended surface plane, so there is some allowance for finish coat plaster. Base-coat does not have to be perfectly flat, or free of tool marks. Finish coat plaster is made from slaked lime and gauging plaster(aka plaster of paris). High quality type S finish lime, made from dolomite limestone, is easy to work with and gives good results. Finish coat plaster application is a learned skill, and not easy to describe in detail. As soon as the plaster is mixed, it begins to set up, and will harden in less than 30 minutes. You have to work fast, and there is a limit to the size, in square feet, that can be done in one mix. If the base-coat plaster is fresh, and still damp, then no misting will be required. If the base-coat has thoroughly dried out, it will rob moisture from the finish coat plaster, and interfere with both application and cure. Misting the base coat with water, before troweling on finish coat, will prevent this problem. If you decide to teach yourself how to apply finish coat plaster, my suggestion is to start with an area around one square foot, for your first trial. With initial success, you will gain confidence, and can begin make larger mixes, and plaster larger areas. The wall doesn't care if it gets plastered in small increments or in one fell swoop.

  • ericwi
    17 anni fa
    Ultima modifica: 9 anni fa

    From the photo you provided, it is clear that there is a wall stud located about 8 inches from the right corner. This stud, to the right of the large drainpipe, is going to be used to attach and support your lath, on the right side. Therefore, it will be neceassary to remove additional plaster to gain access to this stud. You will likely not be happy to hear that the hole must be made larger before it can be fixed properly, however, there is good news. The raw materials used in plaster repair are relatively inexpensive. If you were to use wire lath, pre-mix base coat plaster, type S finish lime, and gauging plaster, then the total cost for raw materials would be under 200 dollars.

  • brickeyee
    17 anni fa
    Ultima modifica: 9 anni fa

    Find a copy of "Plastering Skills".
    It has all the info you need.
    While stright lime putty plaster was common in Europe, in the US the addition of plaster to shorpten the curing time has always been very common.
    Lime putty hardens by reacting with CO2 and takes a very long time.
    By adding plaster you can have the material harden in a few hours, then continue to cure for an extended period.
    It typically can be painted and finished within a week or two, instead of the up to one year wait to finish a stright lime putty wall.
    If additional moisture resistance is desired Keen's cement can be used in place of plaster.

    One of the hardest things about finishing plaster is starting off woth a rough surface and achieving a flat and uniform surface. A number of special tools are used, but the Darby is probably the one used to establish the large flat areas. It is a wooden board about 36 inches long and 2 inches wowith a round handle ant one end, and a hand grip at the other. By holding the round handle in one place and using the hand grip to swing the Darby in an arc large areas can be flattened quickly.
    A pass with a stell trowel is then used to start the smoothing process.
    When the plaster has taken a good set, it is splattered with water and a steel trowel again used to create a smooth and compacted surface.
    Using stright plaster results in a setting time that is to fast, but the lime-plaster mix typically starts to harden within a few hours allowing ample time to work the surface smooth.
    Expanded metal screen is a comon base for 3 coat, with gypsum backer board as the base for 2 coat plaster.
    If real backer cannot be found even 3/8 drywall can be used.
    The second coat is about 1/4 inch thicjk and sanded, while the top coat is ether lime-plaster with more plaster than the base coat. Sand can also be added to the finish coat if desred to produce a slightly more textured surface.
    Even two coat plaster is a big job, and using a mortar mixer to make the lime-plaster mix is usually required for larger jobs.
    A layer of 3/8 drywall followed by Easysand or Durabond can produce the same finish without the work of two coat.

  • zenpotter
    Autore originale
    17 anni fa
    Ultima modifica: 9 anni fa

    Wow, this is a lot to digest at once. It isn't something to jump right into. One thing I didn't mention in the original post is that there is a hole in a closet. That will be our practice site. We many even need to enlarge it to get lot' of practice.

  • brickeyee
    17 anni fa
    Ultima modifica: 9 anni fa

    Just a trick about 'enlarging holes' to find a stud.
    It is far easier to attach some 1x2 tothe back of teh remaining plaster bridging the opening and use that to attach the backing (expanded metal or backer board) than to bother enlarging a hole to a stud.
    The 1x can be cut about 12 inches larger than the opening and 2 drywall screws used in each end to anchor to the back of the remaining plaster.
    If you do need to enlarge or shape a hole, a rotozip makes short work of cutting plaster (keep a shop vac handy sine it dioes kick a decent amount of dust up).
    You can also use a sawzall to cut plaster, but if you have wood lath you ned to be very careful to avoid breakingthe plaster keys and pulling the wood off portions you intend to keep. Using a long blade (8 inches) and keeping it as close to parallel to the wall surface (just enough angle to cut through the plaster and lath) helps change the direction of force applied to the plaster and lath.

  • zenpotter
    Autore originale
    17 anni fa
    Ultima modifica: 9 anni fa

    brickeyee, thank you for the tips.

  • sombreuil_mongrel
    17 anni fa
    Ultima modifica: 9 anni fa

    And use a bonding agent like "Link" or "Plaster Weld" on the broken edges of the old plaster, and on any wood lath that you reuse. It will really help prevent the patch from shrinking away. Used between the scratch coat and the brown coat, it permits more working time by preventing the scratch coat from drawing out the moisture from your fresh brown coat.
    Casey

  • ana_m
    17 anni fa
    Ultima modifica: 9 anni fa

    Here is some info that may assist you in weighing your options.

    Here is a link that might be useful: Technical Preservation Brief 21: Repairing Historic Flat Plaster Walls & Ceilings

  • zenpotter
    Autore originale
    17 anni fa
    Ultima modifica: 9 anni fa

    We will look for the Link or Plaster weld.
    ana, that link is very good. It is direct and to the point. Thank you.
    Pauline

  • bullheimer
    17 anni fa
    Ultima modifica: 9 anni fa

    i am a hack. i have used red (harder) taping mud for alot of plaster repairs, both over lath after wetted down. or over sheet rock in very thin layers. it has been a year with no cracks. knock knock. always let it dry first before adding another layer. always wet plaster or wood first before the next layer of plaster. i'm happy with what i got. i dont know how long it is spzed to last tho. dont use the blue taping mud: too soft.

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