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The defect you describe is fondly referred to in the trade as "nail pops". After a house is built, the wood framing tends to lose moisture once it is no longer exposed to the elements. The wallboard, which had been firmly nailed or screwed to these wall framing members, or studs, suddenly has a slight gap behind it… gasp… the wood has shrunken away! The nail pops occur when either normal seasonal shifting in the house or the touch of a human hand (or head… or foot) causes the wallboard to move towards the stud. The nails, of course, remain in position. The compound covering the nail heads is pushed outwards, forming the slight rise, or "pop".
To perform a repair you need to do two things. First, scratch the wallboard compound from the head of the fastener to see if it is a nail of screw. If it is a nail, hammer it back in. If it is a screw, turn it until is below the level of the wall..
Next, you must add additional fasteners to stabilize the wallboard so that the "pop" doesn't recur. Simply driving in the old nail/screw is not sufficient. Press the wallboard solidly against the stud and install one nail or screw a few inches above the pop, and another a few inches below it. It is not necessary to remove the original fastener… just drive it in so that it is below the level of the wall. Once the wallboard is solidly fastened, cover all the nailheads with a coat or two of drywall compound, sanding as necessary after the final coat dries.
Sometimes, this can become a "Rube Goldberg"... fixing one nail pop causes another to appear. This means that there has been excessive shrinkage in the wall studs, and you will have to do more banging, screwing, and patching to get the job right!
There are a number of ways to approach this repair, depending on the severity of the problem. One way to repair a small area of plaster that has released from the lathe is to chisel out the loose plaster and replace it with wallboard. It is generally acceptable to leave the lathe in place and screw the wallboard directly to it as long as you can screw the wallboard firmly to it. If the lathe is damaged so that there is no screwing surface (angry feet through walls can cause this interesting decorative effect), cut the wall open just wide enough to expose a wall stud and bridge the gap with the wallboard.
Instead of cutting the stud-to-stud opening, you could instead attach 1x2 or larger wood strips across the hole, screwing through the plaster into them so that they bridge the opening and give you a strong nailing surface. You may have to use a masonry bit to predrill the holes for the screws and make a slight depression in the surface of the plaster with a larger masonry bit to "countersink" the screw heads. You don't want the screw heads to show! Get the feeling that working with plaster is not as easy as working with wallboard?
Cut the wallboard to match the shape of the plaster hole, leaving about a quarter inch open around the perimeter of the patch. Use wood shims to raise the level of the wallboard so that it is slightly lower than the level of the plaster. If you are lucky a thin pre-made wood product such as lattice might do the job. If not you will have to cut custom wood shims on a table saw.
Then again, shimming might not be necessary depending on the thickness of the plaster. If standard 1/2" wallboard is too thick and produces a level or raised surface, use 3/8" wallboard instead. The reason I suggest having the wallboard slightly beneath the surface of the plaster is because plaster walls are not always of uniform thickness. "Picture perfect" wallboard will almost never make a good patch without some creative filling.
Slightly dampen the plaster on the perimeter of the patch and the wallboard with water. Apply a stiff mix of Plaster of Paris to the 1/4" gap, pressing it deeply into the gap and also pressing it against the old plaster. Plaster of Paris expands as it dries, filling the opening tightly. It will also seal the damaged edges of the plaster so the final finishing will wallboard compound won't dry too quickly. Plaster of Paris sets quickly so don't dilly dally around! This is why I use it instead of slower drying patching plaster. To avoid having to sand the Plaster of Paris (which can be done but is a pain), make sure the level of the plaster is below the level of the finished surface.
Let the plaster set hard... usually less than a half hour. Now you can begin the fun and artistic part of this repair... smoothing the patch. Apply a coat of wallboard compound with a wide wallboard knife over the entire patch, bringing it slightly above the level of the original plaster and "feathering" the repair out beyond the patch. Don't expect a perfectly smooth surface with the first coat. Allow a day for the first coat and the plaster to dry. You will use multiple coats and a final sanding to obtain a perfectly smooth surface that will blend your patch into the rest of the wall.
Sometimes if a plaster surface is fairly solid but has loosened from the lathe, it can be solidified by reattaching it to the lathe, or "keying" it. This is done by drilling a number of holes in the plaster with a masonry bit and finishing them with a cold chisel so that spaces between the lathe are exposed. Space the holes a foot or so apart, vertically and horizontally.
Dampen the old plaster slightly and press Plaster of Paris into the hole so that it pushes through the lathe. You might want to put pressure on the wall while the plaster dries to keep it firmly against the lathe. You should keep the wall absolutely immobile overnight so the plaster becomes extremely hard. Once fully set, it will bind tenaciously to the lathe, holding the wall firmly in place. Finish repairing the holes with wallboard compound.
As an alternative, you could also screw the wall back against the lathe using 2" drywall screws. This method is less sure than the plaster key method because you have no way to know how strongly each screw is holding in the lathe, especially if the lathe is old dry wood. However, locating the wall studs and adding additional screws through the plaster into them can't hurt!!
If the newly firmed wall has developed unsightly "spider web" cracks, you can apply a special wallpaper to restore the surface to pristine smoothness. Check with your local paint/wallpaper store for the correct product. Of course, using standard wallpaper will also mask these imperfections if you prefer to have this big job end a little more quickly... without the finish painting and seam covering!
You are "on track" and your plan seems well thought out! You should pay special attention to steps (3) and (4).
IF the drywall turns out to be solid after it dries, you might not have to replace it. Killing the mildew with bleach and priming with Kilz or an equivalent oil-based stain killer should give you a good, paintable surface. If the drywall is solid... but a little "bumpy" or uneven because the facing paper is loose... score the paper with a utility knife (don't cut deeply... just the paper!) and peel it off. Then use drywall compound to level and smooth the surface prior to priming/painting. Or just use compound to smooth the area if the defect is really minor.
It isn't absolutely necessary to clean the wood, even if it has mildewed. Once the source of the moisture is gone and the wood dries out, the mildew will cease to grow. It is true that mildew spores can remain alive for long periods of time with no water, but if you fix the leak there should be no recurrence of mildew growth. Of course, if you have any "hygienic" or allergy-related reasons to clean it please do.
I like to use the pre-mixed mildew-killing sprays with chlorine bleach that are available for bathroom use. They are very strong and effective. Since you may be spraying upwards, be careful to protect your eyes and don't breathe the spray. You shouldn't need a respirator, but if you think you might inhale the mist use a dust mask, which will at least catch the droplets. Though the instructions call for rinsing the treated surface, you need only to wipe it with a damp sponge to get off any loose dust, especially since you are going to prime the drywall surface and repaint. I have not found the dried bleach residue to affect the adhesion of Kilz at all! Not much does!!
Also, don't worry about rinsing the bleach from the wood... the action of the bleach will be short-lived and will not cause any damage to the wood if you don't rinse it. You might want to sponge off any excessive amounts of mildew if you have grown a fungus-forest up there!!
Pound in the offending nail. Then, put a nail or, preferably, a drywall screw above it and below it into the stud, spaced a few inches away. Patch and paint. If your problem is under the tape, work right through it! It is unnecessary to cut the tape away unless it has loosened from the wall. Then, you should bend the tape up, slather a little wallboard compound underneath it, and press it back into place.
When you say dent, I say drywall… or gypsum panel… or wallboard… all names for the gypsum-based, paper-covered construction material of choice for modern walls and ceilings. (SHEETROCK©, another oft used name for drywall, is a registered trademark of the USG Corporation.) Plaster… a Portland cement-based product… doesn't dent because it's very hard. However, with enough "persuasion" it can break or crack!
Small dents or defects in walls are easy to fix with any of the patching compounds available for wallboard, regardless of the actual type of wall. Of course, larger repairs in plaster will need a special setting product made for plaster repair.
For drywall, though, the easiest products to use are the premixed,
lightweight spackling compounds, available in small plastic tubs or gallon
sizes. Regular or lightweight wallboard compound is also an excellent choice for
this sort of repair, but since you must purchase a gallon minimum it makes
little sense unless you plan on going on a "denting spree"! Besides,
once the seal on the container is broken, drywall compound does tend to dry out
in the can over time. A year from now when you need it again it just might be
somewhat lumpy and unusable.
All you need to do is apply it to the dent with a three inch wide flexible putty knife for any dent up to that width. Use smooth strokes to fill the crevice and to be sure that the spackle has stuck to the wall. Be neat and don't build up the spackle. When it is fairly smooth, stop and walk away. It is very difficult to get a perfect fill the first coat. The larger the repair, the harder it is! So go have a Perrier, watch the game and give the spackle some time to dry… at least four or five hours. I know… the labels say that they can be painted over almost immediately. That is true for very small holes, but in the case of a dent or larger fill, the product will smear if not given adequate drying time.
Sand the patch lightly with a 120 grit sandpaper to smooth it off. If you are satisfied with the repair, you can proceed to touch it up with paint… no need to prime these products if you are using a high quality latex wall paint. But if the patch is not full and level, apply a second coat of lightweight spackle and repeat the process.
I make the distinction between the "lightweight" spackles and the old fashioned plain spackle. Good ol' plain spackle… which comes either premixed or in a powder form… was designed to be used primarily on small plaster repairs, not on softer, paper-faced drywall. In my experience, I have found that spackle tends to dry so hard that it is almost impossible to sand without causing collateral damage to the drywall! Because of this hardness, there have been a few occasions where I have found it easier to just cut out the spackle rather than waste time sanding it. So if you ever use plain spackle, be very sure that you smooth it carefully and use multiple coats instead of building up the repair with one heavy coat.
Those spidery cracks are typical of old plaster and have been caused by years of stress on the walls. (I feel that way sometimes myself!) Simple patching is not practical since there are so many cracks and they are too fine to hold a patching compound. The amount of labor you would need to invest to open the cracks up sufficiently for patching is better spent elsewhere, such as intense solitaire playing!
In my opinion, the best repair for you would be to cover the walls with a special type of wallpaper designed to restore the wall surface. Any paint or home store can get it for you though most stock it. Do all minor repairs, such as hole filling, before applying the paper. The better the smoothness of the underlying wall surface, the better the final results will look. Prime all repairs with Kilz or another stain killing primer before papering. Ask the paint store for recommendations for sizing (a special type of primer to prepare walls for wallpapering) and the appropriate paste… unless the paper is pre-pasted!
Those spidery cracks are common and annoying which is why this wallpaper product was developed. Unlike patching compound, the paper will flex with the walls and remain crack-free for years. The best part is once the paper is applied and painted, your walls will look like new. You may treat the seams with a light coating of drywall compound, sanded smooth, to make them invisible. Of course, you must prime all the walls again before painting with your finishing paint coat.
Technically speaking, all taped seams should be smooth and dust-free before priming and painting. Once painted, it is virtually impossible to sand them smooth regardless of the type of paint used. This is a common aesthetic problem and not just for amateurs... I have seen many pro jobs that were left in a somewhat rough state for the painters. Sometimes lighting conditions make it difficult to see how smooth the joint is until after painting, where the more uniform color showcases the defects.
But never fear... it's not too late! I suggest putting a broad skim coat of wallboard compound over the rough area, let dry and sand smooth. No wall preparation is necessary unless you used a semi-gloss paint. Then I would suggest a light sanding of the paint with a 120 grit paper before applying the fresh wallboard compound.
If there are still uneven areas, touch them up with another skim coat of compound. Sand off any roughness and use a damp sponge to remove any dust and also to smooth down any sandpaper lines of small defects. This additional TLC (tender loving care) should make the joint smooth as a baby's behind!
There is one quirk with some drywall tapes. Some have an "accentuated" fold line down the center which can stand out if not covered with an adequate layer of compound. So I routinely install drywall tape with the high-side of the fold line towards the wall. This would be the same direction you would install the tape in an inside corner... except you don't fold it!
Unfortunately, paint does not have enough thickness to mask the painted "outline" of the beams you removed. The line will stick out like a sore thumb. Adding joint compound to paint is an time proven and inexpensive way to add texture to a ceiling or wall but will not give the coverage you desire, either.
So it is essential to use wallboard compound to smooth out the paint level. First, try to remove any raised ridges or paint with a scraper, sandpaper or razor knife. This way you will use less compound and thus have less possibility of a visible rise in the wall at each of these repairs. Then, apply enough compound to completely cover the defect, "feathering" the edge of your repair out at least 6-10" outside the perimeter of the repair.
After the first coat dries, sand or scrape off any peaks or lines in the compound and apply a second coat, again feathering it out a few inches beyond the first patch. Sand the repair smooth. Sometimes a third coat is necessary, depending on the thickness of the fill and the amount of shrinkage in the compound. I prefer to use "light weight" joint compound for these repairs. It handles somewhat like standard joint compound but has less moisture and more body. It hardly sags at all in thick applications and shrinks very little, making many three-coat jobs two-coaters, and some two-coat jobs one-coaters! A real time saver in a can!
The enemy of all wall or ceiling patches is shadows. Low profile patching is the goal... so keep the compound as thin as possible while still masking the ceiling defects.
You appear to have done the cosmetic repair correctly. What you haven't done is solve the underlying problem… the wall is moving! First, a nail pop primer… nail pops are visible dimples in the wall over the wallboard nails or screws. This is caused by movement in the wall due to a space between the wallboard and the wood wall studs. This can happen for two reasons… shrinkage in the wood or improper nailing/screwing. This is a common and annoying problem during the first few years in new construction, so much so that it has become common for contractors to use construction adhesive on the studs to keep stud and wallboard blissfully together!
Though some nail pops proudly display themselves without warning, many lie in wait until someone leans on the wall… oops… or during routine repairs such as picture hanging or even painting. The wall suddenly moves, causing the nails to push on the wallboard compound covering them. The pops appear like mushrooms on a damp lawn… as if you didn't have enough work to do!
Simply repairing the visible wall damage… the "pop" or dimple caused by the movement of the wall… is not enough. The pop will reappear… guaranteed… unless you take steps to tighten up the wallboard. Some folks think they can take the easy path and simply bang in the nail or tighten the drywall screw. Sorry… usually not enough. The best repair is to install a drywall screw three inches above and below the pop while pressing the wallboard against the stud. This action both tightens the wall and gives support to the weakened drywall around the pop.
Be prepared (not scared, just prepared) for a few more nail pops to appear along the same stud (or even in adjacent studs) as you do this repair. By disturbing the wall, you are arousing the nail-pop demon! Boogah! Boogah! Get this little devil under control by doing the same aforementioned procedure on all the subsequent pops and I can give you a 99% guarantee that this is one home repair you will not have to repeat!
Contact paper? Oh boy! The adhesive on contact paper is very strong and very difficult to remove. Because the adhesive is also water-resistant, standard wallpaper removal products will not have any effect.
Instead, use a hair dryer to heat the contact paper. The heat will soften the adhesive and make removal much easier. Start at a corner and pull on the paper as you warm it. The warmth may also restore a little of the flexibility to the plastic so it is less likely to split as you remove it. Be patient and take your time or you may do incredible damage to the walls... especially if they are paper-faced wallboard!
Once the contact paper is off, you can use an adhesive remover on the walls to strip the adhesive residue, if any. Use a "citrus"-type adhesive remover rather than a solvent-based one since you may soften or even remove the paint with the solvent. Prime the walls before repainting to assure proper finish paint adhesion.
I feel your paint! Errr... pain, that is! Isn't it amazing how "white" a ceiling can seem until you put a few dabs of fresh paint on it?
Fortunately for you, white is a relatively easy color to work with. Go to your hardware or paint store and purchase a tube of black pigment. Add a very tiny amount to some of your white paint and mix it well. With a little experimentation and lots of patience, you should be able to find a shade of "off white" that more closely approximates your ceiling's current condition.
Most of the textured surfaces you see outdoors are stucco, a Portland cement-based texture coating that is suitable for inside or outside use. The plaster-like texture paints, though, are not rugged enough to withstand outside exposure. Exterior paints have certain qualities that allow them to stand the rigors of the weather... chemically-enhanced mildew resistance, moisture resistance and sunlight resistance. Texture paints tend to give a soft surface with some porosity and virtually no mildew resistance.
Since stucco is not designed to adhere to drywall, I wouldn't recommend using it for your application. However, all is not lost. Apply your interior texture paint... but once it is completely dry apply a coat or two of exterior paint right over the top of it! You will still have the attractive texture, but the exterior paint will act as a barrier to the limited exposure to the weather your ceiling will have. Then you have all bases covered... and the ceiling!