How To Repair Deep Cracks In Prewar Plaster Walls

Piece of cake Set up for Croaky Plaster Walls (and Ceilings) An Illustrated, Stride-by-Pace Guide to the Best Way to Re-adhere Loose Plaster on Walls and Ceilings

Mypsum plaster walls are both the delight and despair of owners of heritage homes. It'south piece of cake to get jealous of your neighbour's drywall – the lack of cracking, the advent of an absolutely flat, smooth wall, and the fact that he can hang a moving picture without rock-boring tools. Your plaster walls are too thick for current door and window jambs, so every new door or window has to exist ordered with a costly special jamb, or has to be modified on site.

Talkin' Plaster

A Glossary of Plaster & Drywall Terminology

Like all fields in the building trades, plastering and drywall have their own peculiar terminology.

Here is some mutual plaster and drywall terminology as used in the Mid-West. In your locality, there may be slight variations.

Blueboard or Blueish lath: A term commonly used in the construction trades to mean plasterboard. Another common name is stone lath.

U.Due south. Gypsum originally colored its plasterboard blue to distinguish information technology from its other gypsum board products. Other manufacturers adopted the color scheme.

Brown Glaze: The second coat of a three-coat plaster wall or ceiling system. The brown coat is the leveling coat applied over the first or "scratch" coat of gypsum plaster. It is typically about three/8" thick.

Whatsoever unevenness left in the scratch coat is removed by the brown glaze which leaves a flat, level surface for the final or "terminate" coat. The brown glaze is no longer chocolate-brown in color but the name persists from the days when the hydrated lime second glaze was darker than the final or white glaze.

Color Glaze: See stop coat.

Drywall: The most common name for gypsum drywall. Also run across: Sheetrock.

Terminate Glaze: The concluding glaze of a three-glaze plaster wall or ceiling system. It is applied to the second or "brown" coat and is finished to a shine surface ready for paint or wallpaper.

The final (finish) coat is unremarkably hydrated lime plaster or a blend of gypsum and lime plaster considering lime plaster works to a smoother finish than the stronger merely coarser, gypsum plaster. Information technology is also called the white glaze (from the colour of lime plaster which is whiter than greyness or dark-brown gypsum plaster under it), especially by old-time plasterers; and may also exist called the color coat because chemical tints were often added to the lime plaster to requite the wall its last color.

Finisher A person who tapes and finishes gypsum drywall. Rockers hang the drywall, finishers stop information technology. Rockers are usually not finishers and vice versa.

Greenboard or Green board: A type of gypsum drywall suited for utilize in clammy (but not wet) areas such every bit bathrooms. U.South. Gypsum originally colored its h2o-resistant gypsum board dark-green to distinguish information technology from its other gypsum board products. Other manufacturers adopted the color scheme. The newer purpleboard and paperless gypsum drywall have at present replaced greenboard for applications where mold and h2o resistance is necessary.

Gypsum Board: A console of gypsum drywall.

Gypsum Drywall: Panels fabricated of a sandwich of gypsum plaster pressed between 2 sheets of paper. The panels are used to cover interior walls and ceilings and are the near common materials for that purpose since gypsum drywall replaced true plaster in the 11940s and '50s. It may besides exist used equally exterior wall sheathing, in which case a water-resistant cloth replaces the paper. Synonyms include gypsum boards and drywall. Also erroneously called plasterboard.

Gypsum Plaster: A plaster mixture containing gypsum equally the bonding agent. Discovered in the 18th century, gypsum replaced lime as the preferred bonding amanuensis in plaster and cement because it is stronger than lime and cures much more apace. Commonly used as the outset and 2nd coats of a plaster wall, with the smoother lime plaster used equally the terminate coat.

Horsehair Plaster: An early on form of hydrated lime plaster to which horse hair was added for greater strength. Now rarely used except in celebrated restorations. Information technology has been replaced by fiberglass in common use considering fiberglass strands are stronger (and considering horses have raised strenuous objections).

Lath: Thin woods strips or metal mesh attached to wall studs and ceiling joists to which plaster is applied.

Lather: (Pronounced "Lath er" with a hard "Thursday" – as in "bath", not "lath er" with a soft "Thursday" like in shaving foam.)

A person who attaches lath to wall studs and ceiling joists. Once the lather is done, the plasterer applies plaster to the board.

In earlier times, Lathers were essentially amateur plasterers. Plasterers themselves seldom attached lath – as well menial a chore for a skilled plasterer. Today both lathing and plastering are unremarkably washed by the same person.

Lime Plaster: A plaster mixture containing hydrated lime as the bonding amanuensis rather than the more common gypsum. Until the use of gypsum was developed as a bonding material in the 18th century, this was the only blazon of plaster available. It is common to use gypsum plaster as the undercoats in a plaster wall because gypsum plaster is stronger than lime plaster; with lime plaster as the final coat because of its smoother finish.

Mudder A slang proper noun for a plasterer or drywall finisher but just if y'all are close friends.

Plaster: A composition of hydrated lime or gypsum, sand, h2o, and sometimes hair or other fiber, applied equally a thick paste to walls and ceilings and immune to harden through a chemical process. The sand (or sometimes chalk) is the aggregate that gives body to the material, the lime or gypsum is the adhesive that bonds the sand particles together. The water is the carrier that makes the fabric workable.

Plaster is similar to concrete and stucco. For plastering a wall, gypsum mixes are unremarkably used for the first ii (scratch and brown) coats of plaster and a lime mix for the final glaze because it finishes to a smooth, hard surface.

In before times horsehair was used to strengthen the plaster and brand information technology less subject to cracking. Today fiberglass strands may be used for the same purpose.

Although nosotros routinely refer to lime plaster and gypsum plaster as distinguishable products, in practice nigh commercial plaster mixes contain both lime and gypsum. Lime plaster simply has more than lime, and gypsum plaster more gypsum.

Plasterboard or Plaster Board; A gypsum board production used as an underlayment for moisture plaster. Too known as plaster lath and rock lath.

Plasterboard was made in solid, perforated, insulating and even acoustical versions.

This is an illustration from a 1954 issue of Popular Mechanics showing perforated plasterboard being installed.

Plaster penetrated the perforations and formed "keys" that solidly gripped the lath. As confidence in the power of plaster to stick to plasterboard grew, perforated board savage out of favor. Today, only solid board is readily available.

The original substrate under moisture plaster was wood lath – sparse strips of forest attached to studs over which three coats of plaster were applied. In the 1930s this was supplemented with expanded metallic lath which was faster to install and bonded better to the plaster. In the 11000s plasterboard began to replace both woods and metallic lath.

It was immediately popular because it substituted for the starting time, or "scratch" of plaster. It was not only faster and cheaper simply made a ameliorate wall. Plasterboard was brusk-lived, yet. Information technology rapidly morphed into gypsum drywall that needed no plaster coating at all. The surface of the lath is also the wall's surface.

Plasterboard is made in solid, perforated, insulating, and fifty-fifty acoustical versions.

The term plasterboard is ordinarily used, fifty-fifty by people who should know amend, to refer to gypsum drywall simply this is an wrong use of the term that causes a lot of defoliation.

Plaster Lath: See plasterboard.

Plasterer A person who applies plaster to a wall or ceiling. The plasterer follows the lather who attaches the board to the wall studs. He or she, in turn, is followed past the finisher who applies the final or finish coat. May besides refer to a person who applies stucco coatings to exterior walls. Today'southward plasterers are often chosen on to utilize stucco, unlike prior times when stuccoers and plasterers were ii different trades.

Purpleboard or Purple Lath: A blazon of gypsum drywall resistant to water and mold for employ in damp (but not moisture) areas. It has largely replaced greenboard for employ in bathrooms and other damp areas.

Rock Lath: Meet plasterboard.

Rocker: Slang term for a person who hangs gypsum drywall. From the brand name of the original gypsum board, "Sheetrock" by U.S. Gypsum. Hanging gypsum drywall is similarly referred to as rocking.

Scratch coat

Scratch Glaze: The kickoff coat of a three-coat plaster wall or ceiling organization. The scratch glaze is the structural coat of the wall. Information technology is forced into the gaps in the wall lath and then that when it has cured it forms a stiff mechanical bond with the wood structure of the wall. It is unremarkably practical about 3/8" of an inch thick and scored with a scoring tool before information technology has cured. The scores or scratches help the second or "brown" coat grip the base coat. Subsequently 1950 plasterboard (or plaster lath) replaced the scratch coat in most residential walls and ceilings.

Sheetrock®: A merchandise proper name for gypsum board manufactured past United States Gypsum (USG). Information technology has migrated into the vernacular and the "sheetrock" is commonly used to mean gypsum drywall. Sheetrock was the get-go widely accustomed gypsum drywall product in the U.South., and "sheetrock" has been used to refer to gypsum board for then long that gypsum board installers are normally referred to in the structure trades as rockers.

Truthful Plaster: A term used to describe plaster for the purpose of distinguishing it from gypsum drywall.

Wallboard or Wall Board: A widely used slang term for gypsum drywall but also used to mean plasterboard. Unless yous know the context, its use is unremarkably ambiguous, and it should be avoided.

Moisture Plaster: A term used to depict plaster to distinguish it from gypsum drywall.

White Coat: Run into finish coat.

Merely, iii-glaze wet plaster walls are amend walls. It'south just that subsequently repairing the umpty-umpth crevice, the practiced things about plaster seem to become lost in the well of aggravation.

True plaster is unmatched in durability and strength. It is a class of concrete and very tough stuff. Plaster resists burn ameliorate than gypsum drywall and greatly reduces sound manual, which results in a much quieter firm.

Information technology is a hostile environment to mold and mildew because, dissimilar drywall, it has no newspaper facings. It is the paper that mold and mildew feed on. And, its loftier tensile strength makes it impervious to almost damage caused past blunt force – beingness hitting by the doorknob, for example. Drywall volition dent readily, plaster shrugs it off with an impish grin.

Still, after the ump-teenth spider crack trying to hang a mirror, there is the temptation to just do away with the old plaster and replace it with nice, new, crack-less, polish drywall.

Our advice, after working with onetime houses for many years, is don't do information technology.

True gypsum plaster, with all its imperfections and evidence of historic period and use, is a part of the original fabric of your house. It is a major architectural element of the distinctive await, feel, and character of your home. Its contours and slight imperfections are an indelible monument to some of America's early on master craftsmen. Then, if only for the practical reason that it makes a ameliorate wall, plaster walls and ceilings should exist left in identify and restored, if at all possible.

Besides, restoring plaster walls is almost always less costly than replacing them. And, nosotros are huge fans of less costly. We are likewise big fans of the de minimus dominion.

The De Minimus Rule Ever do the least to your old house that volition solve the trouble.

Otherwise, you take a chance doing real damage to its essential character. Plaster is a significant part of the "fabric" of the building. Much of the edifice's history is documented in the layers of paint and paper institute covering erstwhile plaster.

How Plaster Becomes Detached from the Wall

Until the 1930s, plaster walls were fabricated with forest lath and lime or gypsum plaster.

Lime plaster dates from antiquity. It has been plant on buildings from the Minoan culture on Crete and structures dating to 7200 B.C.E. at an archaeological site in Jordan.

It is composed of hydrated lime, sand, h2o, and some grade of pozzolan material formed originally from volcanic ash. In more modern times it was usually reinforced with horsehair – much to the irritation of a good many horses. Its master drawback was its very slow curing time: often months.

Faster setting and stronger, gypsum plaster began taking over from lime plaster in the 19th century, and by 1900, most plaster was gypsum. Gypsum plaster is stronger than lime paster and sets in virtually 72 hours. It can be practical in thinner, lighter coats and profoundly speeds structure.

During the 1930s wood lath gave mode to metallic lath and finally to plasterboard or "rock lath" which was used until the 1950s post-war housing boom when an entirely new wall system, gypsum drywall, replaced moisture plaster walls in most localities. This is the wall system yet in use in contemporary structure.

In some areas of the country, paster on rock board is still the preferred wall – well-nigh notably in New England and the Mid-Atlantic states. Despite the claims of its admirers, it really has no advantages over skim coated gypsum drywall.)

Wood board (or split lath) is just thin (1-one/two" 10 one/4") strips of woods, usually pino, nailed horizontally over the wall studs about 1/four" apart. This gap allowed wet plaster to be pushed into the spaces between the lath strips where it slumps down on the inside of the lath.

When cured, the slumps course plaster "keys" that act as a mechanical bail, tying the plaster to the wall framework. Since plaster does not stick to woods, these keys are the merely connection between the wood-framed wall and its blanket of plaster.

The base or "scratch" glaze is scored to provide a rough surface and so the side by side ("brown") coat volition attach. The brown coat is as well scored but more lightly, to help the finish glaze bond.

Once cured, wet plaster is a tough, durable, rigid material that, if left undisturbed, will final nearly forever. Unfortunately, things can happen to disturb plaster. The near mutual are settling and water.

When houses settle (and all houses do settle to some extent), the wood framework of the wall shifts, and if it shifts plenty it can break off the keys holding the plaster to the wall.

Water can take a like effect. Wood board naturally swells when exposed to h2o. Seasonal changes in humidity are unlikely to be a problem just if the wall gets really wet, equally from a leak, the wood may swell enough to interruption the keys.

If enough of the keys are cleaved, the plaster becomes discrete from the lath. Detached plaster tends to cleft or fifty-fifty, if the detachment is over a big area, fall off the wall.

It is possible to accept small cracks, especially around the tops of doors and windows, with minimal or no plaster detachment. But, if yous accept long cracks going beyond or up the wall, then nearly probable the plaster is detached backside the crack. If you have two or more roughly parallel cracks, then the plaster is probably also discrete between the cracks.

Just patching over the crack is not the cure. It is, at most, a band-aid. Equally long equally the plaster remains detached from the wall, the crack will inevitably reappear. Often only leaning on the wall is enough to expose the crack. For the repair to exist permanent, the plaster has to first be re-attached to the wall.

Re-attaching Loose Plaster

Once keys are broken, they no longer mechanically fasten the plaster to the wall. Nosotros cannot recreate the keys, so some other course of reattachment is required.

There are two kinds of plaster reattachment: mechanical and adhesive.

Mechanical Attachment

Mechanical fastening involves the use of the old familiar remodeler'due south friend, the plaster washer or "plaster push". This is simply a thin washer, about the size of a quarter, designed for re-attaching plaster to wood lath.

They have been around for most of a century simply are not a common hardware store item. We usually become ours from McFeely's simply they are available online from several sources.

The traditional washer is galvanized steel, simply we are seeing a lot of plastic washers these days. Plastic is not as strong, is thicker and harder to muffle, and tends to dissever. All-time to use the traditional steel washer.

Their utilise is straightforward. A pocket-sized hole (about three/xvi") is drilled through the plaster but not through the lath. A galvanized flat-caput screw is fitted to the washer and screwed into the wall through the lath.

This creates a new mechanical bail between the plaster and wood wall beneath the plaster.

Plaster washers work well but don't finish well. They stick out from the plaster about 3/16th of an inch (or more than for plastic washers). This may not seem similar much, simply a 1/4" coat of plaster is needed to muffle a 3/sixteen" projection – a fairly thick skim coat. This is not simply a lot of work but often results in an uneven wall that looks patched.

Agglutinative Attachment

More than two dozen years ago, my partner and I were struggling around midnight to get the terminal coat of plaster on a wall repair in his sometime farmhouse nearly Pilger, Nebraska. The plaster washers were making the job harder and much more than involved and we were enough bellyaching.

We started talking about the idea that possibly we could mucilage the plaster to the lath and do away with plaster washers.

The next twenty-four hour period we went to the Large Box lumber store to buy one tube of every kind of construction adhesive information technology sold and started gluing plaster chunks to wood. Amazingly, almost all of them worked – some better than others, of course.

The big problem was that nigh took a long time to set up difficult. A few years later, the Henkel Corp., maker of Loctite adhesives came out with Powergrab^® All-Purpose Construction Adhesive that bonded in a few hours rather than in ii days. We had establish the right glue.

Here'southward how information technology's done.

Just a Few Basic Tools are Required

You will need these tools:

a drill with a iii/16" concrete or masonry bit,
a caulk gun,
a Phillips screwdriver (or Phillips bit for your drill),
a (metal) putty knife,

a set of drywall knives (six", and 12" knives at a minimum),
a drywall mud tray or plaster hawk (tray is easier, militarist is faster),
a painter's five-in-ane tool,
a sponge and saucepan.
a tin of compressed air.
a shop vac, and
drop cloths (lots of them).

You may likewise demand these optional tools:

a spray canteen,
a sanding pole or cake, and
sanding screen or 120 grit open-coat sandpaper.

This safety equipment is required :

a dust mask,
condom goggles,
rubber gloves.

Dust masks and rubber gloves are disposable and should not be reused. They are sold in boxes of 5 to l at your local hardware store. You lot will demand the smaller box.

Rubber gloves are made from latex or nitrile. A lot of people are allergic to latex and don't know information technology. We recommend nitrile gloves. Be sure to go the slightly thicker gloves made for structure work and not the thinner examination gloves used in the medical profession.

No Exotic Materials are Needed

The materials yous volition need are readily obtained from local hardware stores.

Powergrab^® adhesive in a pint tube used with a caulk gun. One tube for every 50 square feet to be repaired.
1-1/iv" wood-thread screws. We utilize drywall screws, cabinet screws, or deck screws – whatever we happen to have lying around. You will demand approximately three screws for every foursquare foot of plaster to be repaired. These and the fender washers volition be used to clamp the wall while the glue dries, and so volition be removed so you can use them on something else later.
Fender washers. One 2" or 3" fender washer with a i/4" hole for each screw.

Drywall summit coat joint compound.
DuraBond setting articulation compound (maybe).
Plaster of Paris.
Windshield washer fluid (to remove wallpaper. (Forget it if y'all don't have to remove wallpaper.).

The Process: Pace by Step

For all-time results, read through the entire process at to the lowest degree once before yous offset, then follow the steps closely. Any questions? Contact u.s..

Alert:
Old Paint May Incorporate Lead

Stop sign

Lead is considered toxic past the EPA which has published guidelines for containing lead in-home repairs and remodeling. Condom from lead paint consists primarily of keeping paint particles out of the air where they tin can be inhaled.

Ever wear a dust mask and rubber gloves, proceed the paint damp with a spray bottle and then the pb does non class dust in the air. Use a disposable plastic driblet cloth.
When you are done, roll up the drib fabric so the particles do not escape, and put it into a plastic pocketbook along with your gloves and mask for disposal. Securely tie the cervix of the bag. One time contained, the atomic number 82 tin exist tending of as ordinary trash.

To learn more well-nigh safely handling lead pigment, read the EPA Pb Renovation, Repair, and Painting Program Rules.

Have Intendance Using the five-in-1 Tool

Scraping on plaster with a 5-in-1 tool is very much similar honing it on a hairdresser's hone. Information technology tin can eventually get razor sharp.

Pace 1 Remove Loose Paint & Wallpaper

Check the wall for loose pigment or wallpaper. All of this has to come off. Trying to bind plaster to loose paint or paper guarantees it will eventually loosen.

The nigh effective tool we take found for removing multiple layers of loose paint and wallpaper is the painter's five-in-i tool. Slide information technology under the loose paint or paper and lift it off.

If the final layer is pigment, then you don't have to remove all the paint, just the loose $.25.

If the final layer is paper, then all the paper has to come up off. Otherwise, it volition absorb h2o from any plaster applied over it and loosen – making a soggy mess of wet paper and plaster that will probably end upwards on the floor.

You can rent a wallpaper steamer from just about any tool rental shop or your local wallpaper shop. We have constitute, all the same, that ordinary windshield washer fluid applied as a spray works nigh too, and is very inexpensive – about $3.00 per gallon.

Removing Painted Wallpaper

Wallpaper that has been painted over is very difficult to removed because the paint prevents the washer fluid or steam from penetrating the newspaper.

You lot need to remove the paint earlier removing the newspaper.

There is a specail tool for this job, the Wagner "Painteater" which uses a annoying wheel to quicly remove pigment. An bending grinder fitted with an abrasive wheel (used to remove paing in motorcar torso shops) is too effective. Both of these are pretty ambitious, however, and may remove more than you lot want to remove.

We simply use an orbital sander fitted with xl-80 grit open coat sandpaper. Unlike removing old paint from forest, you do not have to be peculiarly careful and the result does not accept to be specially neat. All y'all want to do information technology open upwardly the painted layer then liquid tin can get to the paper underneath.

If the wall is covered with alternating layers of newspaper and pigment, you lot may take to practice this several times.

Note that the paint probably contains lead, so take all of the usual lead precautions (see the warning above) including covering all surfaces with plastic and donning goggles and a respirator.

Wet the newspaper with the fluid until it appears very damp, wait a few minutes for information technology to soak in, and scrape the wallpaper off with your 5-in-ane tool or a stiff putty knife. If there are many layers of wallpaper, more than than one application may be required.

The cabinets were pre-state of war and original to the house – unusual since well-nigh Arts & Crafts kitchens were "updated" in the firsthand mail service-war period. (See Arts & Crafts Styles: Craftsman, Prairie and Four-Foursquare Architecture for more on Arts & Crafts kitchens and baths). The original cabinet color was vivid red. This was painted over in yellow, then white.

With olive walls and red cabinets, this was a brilliant, colorful, cheerful kitchen in 1928. And, we hope whoever lived in information technology then enjoyed it a lot.

Stride 2 Mark the Boundaries

To make certain you reattach all of the loose plaster, y'all need to notice and mark the perimeter of the discrete area. The presence of a cleft indicates loose plaster just not necessarily the total extent of the discrete area.

There are ii sure ways to detect loose plaster:

Push on the plaster. If it is loose, information technology will often move and feel spongy, but non always.
Rap on the wall with a knuckle. Detached plaster hounds hollow. Solid plaster sounds, well, solid.

Using the "push button and wait" and "tap and listen" techniques, detect the edges of the detached area, and mark them with a pencil line. You lot don't have to be exact. Close is good enough.

Stride 3 Drill a Lot of Holes

Warning Wearable middle protection whatsoever time you lot are operating a drill or any power tool for that matter. Wear a grit mask when drilling plaster. You don't want to breathe in plaster particles or, worse, onetime lead paint. Dust masks are bachelor in packs of six at whatsoever hardware store.

We need to get glue backside the plaster, between the plaster and lath. To practice this we need to drill three/16" holes using a masonry flake i/2" from any crack, on both sides of the scissure, spaced every three-iv" apart and every 8-10" in the area between cracks.

This process requires a footling bit of a "affect".

Yous want to drill through the plaster but not through the lath. Effigy the plaster to exist well-nigh 3/eight" to ane/2" thick. And so, put tape on your drill bit at the advisable depth. Drill slowly until the drill starts feeling springy. This means yous take probably hitting the lath, so stop. If at that place are footling bits of wood on your drill bit, then y'all have gone far plenty.

To test the hole, button an awl, pocket-sized Phillips screwdriver, or slice of wire clothes hanger into the hole. If the bottom of the pigsty pushes in just a little then springs back, yous have hit lath. If it does not push in or grinds when you wiggle the probe, you are nevertheless in the plaster.

If you accidentally drill all the style through the lath, no trouble. Just move your drill bit about 1/two" right or left of the original hole and drill a new hole. Mark the bad hole by circling it with a pencil. This means, "Don't glue up this hole". If y'all striking the open space between lath strips, do the same thing. Motion 1/2", this time upwards or down, and drill a new hole. Mark the bad hole.

Footstep four Clean Out the Dust

Drilling left a lot of dust and some small plaster particles in the holes. Particles may prevent the plaster from seating to the forest lath and grit interferes with the adhesion of the gum, so we need to get rid of both.

Vacuum out each pigsty with a store vac then blow out the pigsty with compressed air – make certain you are wearing your rubber goggles. Finally, vacuum each hole again to be sure yous got everything. Compressed air in a tin is sold in nigh every hardware or electronics store.

Rarely, only sometimes there is droppings caught at the bottom of a pushed-out section of plaster. This volition keep the wall from pulling in flat unless it is removed. To remove it, drill a serial of 1/4" holes forth the bottom of the discrete surface area spaced nearly 1/ii" apart. Vacuum out the debris.

It helps to put gentle pressure on the slice of board with an awl or screwdriver to help release whatsoever particles that may be wedged in. If some droppings is however stubbornly wedged, a wire coat hanger with a i/ii" right-angle hook at i end can exist used to dislodge any stubborn particles.

Step five Insert the Mucilage

Powergrab^® comes in a pint (small) tube for utilise in a caulk gun. It may come in the larger, contractors' size quart tube but we have never seen it. You will need one tube for every 50 square anxiety of wall. This project was 65 square feet, and so nosotros pulled two tubes out of supply. Cut the tip foursquare and then information technology is slightly smaller than your holes. You want it to fit within the holes you lot drilled so it creates a proficient seal just you don't desire information technology to bottom out on the lath. Cut the hole a little smaller than you think you will demand, and then try information technology. If information technology bottoms out, cut information technology a little larger.

Wall Treatment Archaeology

Removing paint and wallpaper is never a cheerful task but it does requite you a chance to do some wall handling archæology.

Our wall showed only three layers of paint, very unusual for a 90-yr-erstwhile house. The original colour was olive dark-green. The adjacent layer was tan. Both of these were oil-based indicating that the second layer was probably practical in the 1950s. The last, visible layer of paint was latex in white.

Our client elected to return to the olive dark-green paint and bundled her color scheme around that original color. Then, nosotros saved some fries for Sherwin-Williams to colour-lucifer. It matched closely to Ruskin Room Greenish.

We use a Grainger^® dripless caulk gun, which is definitely a pro tool, and expensive as caulk guns go. Information technology works so well, however, that we think it'south worth the outlay. If y'all don't have i, keep some paper towels around to mop up dribbles.

Insert the nozzle of the tube in a hole and press downward and then the nozzle seals the hole tightly. Give information technology about one/ii of a full trigger pull's worth of glue – slowly. Yous will probably feel a footling resistance as the relatively thick adhesive works its style into the narrow space between the plaster and lath. Release the pressure on the gun and remove it from the hole.

Glue each hole the same way, avoiding the bad holes yous circled with a pencil mark. The mucilage may drip a footling out of the pigsty, which is where your paper towels come in handy.

If the glue goes in too easily, then you have probably drilled through the board and the mucilage is simply going into the air. If it blows back right away, then your hole is not all the style through the plaster. Mark this hole with a penciled "10" and move on to the next hole. Come back later and redrill, so mucilage the "Ten" hole.

If you are not sure you are getting mucilage into the expanse between the plaster and lath, here's a simple test. Drill another pigsty 1/2" to the side of the hole to be glued. Continue adding glue until it squeezes out of the exam hole. You tin do this as many times as you like until you go the sense of what a properly glued pigsty feels like.

If your hole is all the way through the plaster but you can't force mucilage into the hole, then the board is probably pressed hard confronting the plaster. To create a picayune infinite for the mucilage, drill a pigsty about 1/ii" to the correct or left of the gum hole, and using a screwdriver or awl, push on the board gently while adding glue. This should give the mucilage enough room to wriggle between the board and plaster.

There is a time limit to this process. Powergrab^® begins to fix after about 15 minutes. And then only glue up as many holes equally you can mucilage and spiral in fifteen minutes. For an experienced operator, this is well-nigh 60 holes. If this is your first time, figure on about 25-35.

Step six Clamp the Plaster

Now we need to clench the loose plaster to the woods lath while the gum bonds. This is done with screws and washers. You can use plaster washers. We did for a few years simply fender washers piece of work better, and they are more widely available at just about any hardware shop or your local body shop supplier.

Y'all will need 2" or three" washers with 3/16" or 1/four" holes. The screws should exist no longer than one-one/four". Any longer and at that place is a gamble of striking power lines or pipes inside the wall – things yous do not want to hit with a metallic screw.

We employ deck screws or drywall screws – any we have on hand. They won't be there long, and we can ever reuse them for something else later.

How to Go on Washers from Sticking

A Reader Tip from David Gabbe:

"Utilise thin brown bundle shipping tape to the side of the washer that presses against the wall. The PowerGrab won't stick to information technology and the washers are ready to reuse for the next section."

"I lay the tape sticky side upwards on a flat surface and drop the washers on. Then cutting into strips and fold the excess record over the top."

Insert 1 screw into a washer then into each hole. Tighten it downward until the spiral is fully seated. You volition see the plaster draw into the wall as the screw is tightened.

Start at the exterior and piece of work toward the centre. This draws the plaster in gradually, reducing the risk of boosted cracking.

If the plaster is very loose and more than 1/4" abroad from the lath, tighten each screw just partway until all the screws are started, then get back and tighten the screws all the way down. This helps prevent further stress cracking in the plaster by moving information technology gradually and evenly rather than all at one time.

When all the screws are set, wash the wall with a sponge and h2o to remove any excess gum, make clean up and call it a twenty-four hour period.

Tomorrow y'all volition remove the screws and washers. Odds are pretty adept (unless you use David Gabbe's shipping tape pull a fast one on) that the washers will exist stuck to the wall – Powergrab^® glues simply almost anything to anything else. Use your 5-in-1 tool to pry them loose. Insert the edge of the tool under the washer and thump it with your hand. The washer volition popular off. If a little paint and plaster come off with it, no impairment is washed. We volition fix this in Stride 8.

It happens very rarely but if some of the plaster still seems a little spongy, no worries. Just drill new holes in the springy areas, add glue and screw downwards overnight. Y'all can do this as many times as you need to until all the sponginess is gone to your satisfaction.

Step 7 Level any Loftier Spots

Not often simply sometimes, in a badly delaminated wall, not every piece of loose plaster will be fully seated against the board. Some plaster bits may have come loose and lodged between the lath and plaster preventing the plaster from fully reaching the lath in some spots. And, sometimes the board itself is deformed or detached or a protruding smash prevents the plaster from seating fully.

There may too be areas where someone in the past has badly patched the plaster. This wall had both issues. In desperately degraded areas, the plaster did not describe back perfectly flat, and in that location was one ham-handed patch task past someone who must take used a butter knife as his chief plastering tool. Anyhow, it was very rough looking.

A main plasterer volition mostly try to fill such defect with new plaster, or interruption out the patch and start over. We want to do neither considering we don't want the unevenness of a heavy mud-over, and we don't want to risk damaging the wall past breaking out the patch. What we do want to do is smoothen down the rough areas to brand the wall ready for our last plaster coat. The all-time way to practice this is with a chugalug sander and a 40-grit belt.

This is messy and creates a lot of dust – a lot of dust – so make sure everything in the room is covered, the store vac is fastened to the sander, and you are wearing an approved grit mask and condom goggles. If you vesture eyeglasses, do not rely on the glasses alone for heart protection. Wear goggles.

Step 8 Fill the Holes and Low Spots

The plaster is now firmly re-attached to the lath, and the high spots have been leveled out. Information technology is now time to start rebuilding the surface of the plaster. If you are not a plasterer, with all the wonderful but cabalistic, plastering tools in your toolbox, no problem. Typical drywall tools volition work just besides, and you are more likely to own them.

Our first job is to patch all the holes we drilled and all the divots left when washers were removed. You can practise this with drywall joint compound and await the two or more days it takes to air dry out. But we like to move a trivial faster than that, so nosotros utilise plaster of Paris.

Plaster of Paris is a setting plaster with a myriad of uses including making castings and splinting broken arms and legs, and, in our case, filling holes and divots. Information technology has a very brusk working fourth dimension, and so mix but as much every bit you can apply in 15 minutes or so – about one pint. Using a putty knife, printing the plaster into each pigsty and so smooth it out.

Mix the plaster in a make clean plastic cup. Do not mix a new batch in a cup that already has old plaster in information technology. It will vastly speed up setting time, giving you lot little fourth dimension to work.

Await at least 45 minutes for information technology to set before proceeding to the next footstep.

Step nine Patch the Cracks

We take re-attached the loose plaster to the board, and this will proceed cracks from getting any worse or new cracks forming. At present we have to bond the croaky pieces of plaster dorsum together.

We have read a number of manufactures and seen a lot of videos in which the cracks are just plastered over with joint chemical compound. This does not work. Even though the plaster is at present firmly attached, merely plastering over the cracks is a virtual guarantee of futurity hairline neat.

What'south needed is a firm bond that joins the two sides of the scissure together permanently and then they cannot separate in the futurity. This requires nylon mesh tape for the structural integrity needed and joint chemical compound to bind the ape to the wall. Joint compound alone will not do the task.

Utilize pieces of tape curt enough to follow the twists and turns of the crack, keeping the crack roughly in the center of the tape. Apply the tape to a vertical crack starting at the lesser and working upwardly. Since most of the states tend to utilize plaster tiptop to bottom, this prevents the taping knife from communicable an border of the tape and pulling it off the wall. If the crack is horizontal, use left to right for a right-hander, right to left for a left-hander.

Some mesh tape is cocky-sticking, some not. If yours is non, you lot will need to apply a thin coat of drywall articulation compound over the scissure before embedding the record in the mud with your taping knife. Some of our plaster guys call back all tape should be embedded, even self-sticking tape because it creates a stronger bond. Others think information technology works just likewise to stick the record to the wall and mud over it – and it takes less time and less work. Personally, I am from the "less work" schoolhouse.

Adhesive mesh tape is piece of cake to apply. Gyre out the length you need, shine it down with your 6" knife. To cut information technology, press against the tape with your knife, and tear information technology. The pocketknife is precipitous enough to easily cut the record. For a good video on applying mesh record, go here.

Mesh tape is never used on inside corners. For inside corners, you need a material that will crease sharply, and mesh tape volition not.

Some pros volition tell you to never overlap mesh tape simply we exercise it all the fourth dimension – just don't build up multiple layers of tape. 2 layers are the max.

Window Screen Canvassing

A Reader Tip from Mitchell Rōem

If you have a lot of cracks shut together, instead of taping each crack individually, you tin reinforce the whole area with fiberglass cloth. This is just a very broad version of fiberglass record – up to 36" wide compared to the tape's iv" width.

Nosotros use it sometimes merely most of the time, nosotros just utilise nylon insect screen – the stuff you put on screen doors.

The technique was introduced to u.s.a. by the tardily plasterer extraodinaire, Mitchell Rōem. Information technology works just as well as fiberglass cloth at nearly 1/tertiary the price.

Window screening comes in 100' rolls but any hardware store will cut but the length you lot need. Be sure to get the fibroid rather than the fine screen and make certain it is nylon, not aluminum or steel.

Since insect screen is non self-adhesive, you will need to embed it in joint chemical compound. Utilise a thin (not more than 1/4") coat of compound the size of the screen plus a lilliputian extra. Lay the screen over the compound, pressing it in slightly in several places to hold it in place. Then, starting at the middle with you 6" pocketknife, embed information technology evenly in the compound. Scrape the excess chemical compound from your knife dorsum into the mud pan or hawk subsequently each laissez passer.

Canvassing

Before nylon and fiberglass were invented, canvas or burlap cloth was used, and it is notwithstanding an selection. but these are more expensive these days than either nylon screen or fiberglass cloth, and harder to work with.

For more on "canvassing" a plaster wall, see Preservation Brief 21: Repairing Celebrated Flat Plaster Walls and Ceilings from the National Park Service.

Regardless of what method you use, utilize drywall joint compound over the tape, tapering the compound on both sides of the tape using an 8" drywall pocketknife (if you don't have ane, a 6" knife works nearly too). This volition give you a taper of well-nigh four-5" on each side of the tape, which is enough. If you exit a ridge or two, don't worry nearly it. Nosotros will scrape these off in the next footstep.

If your wall has missing plaster (the wood lath is exposed), now is the time to patch the pigsty. Use DuraBond® or any similar setting-type drywall compound. Use a thick glaze to the forest lath, pushing it into the spaces betwixt the lath strips. This volition form the keys that lock the new plaster to the lath. Don't fill right to the surface of the wall, keep information technology recessed well-nigh i/viii"

Earlier it sets rock hard, using a scoring trowel (or if you don't have a scoring trowel, any tool that volition score the soft plaster, a screwdriver, or the point on your five-in-1 tool, for instance) to score the plaster. Score in parallel lines about 1/2" apart. The ridges left by scoring are what the next coat will bind to.

After the plaster has set, about 1 hour for DuraBond, apply the concluding coat, finishing it off fifty-fifty with the rest of the wall. If you are unhappy with the final effect, give the plaster a hazard to ready almost hard, then scrape away any ridges and loftier spots. Give it nigh another 60 minutes to harden up, then utilize a very thin coat of regular (non-setting) drywall compound. Don't panic if it is yet not perfectly smooth. We will even it out with the final skim coats of plaster.

At present clean upward and let everything set for about 24 hours. A fan in the room speeds up the process.

Pace ten Apply the Cease Coats

A seasoned plastering professional would probably utilize one perfect cease glaze, accept your generous check, and thank y'all for the work. But, since were are not that accomplished, nosotros are going to apply 2 thinner skim coats.

Get-go, scrape downwardly any ridges you left when taping the cracks. Utilize your half-dozen" taping knife or v-in-1 tool. Drywall joint compound scrapes off easily. Hold the knife at a low angle to the wall and apply the edge similar a paint scraper. If you accidentally dig into the wall here and at that place, no thing, nosotros'll ready it in the adjacent step – but attempt non to do information technology.

You accept several options for the final, skim coat of plaster. You can use actual gypsum/lime top glaze plaster. Information technology is still available from U.Southward. Gypsum and National Gypsum. You tin can ordinarily buy it from your local drywall supplier, although he may spend a long time looking for it in the warehouse. We like Diamond Veneer Finish by USG simply they make several topcoat plasters, all of which will work.

A modern substitute is DuraBond from the same company. Durabond is a setting joint compound intended for drywall but it takes a nice end and cures much faster than true plaster.

Our choice for this job, however, is ordinary topcoat joint compound. Information technology is non every bit hard as truthful plaster (just we volition utilise a fox to arrive nearly equally hard). But, it is very forgiving and much easier to work with, especially if you have non done a lot of plastering.

Some of our plasterers prefer to thin the joint compound a little by mixing information technology with, at most, one or two cups of water per 5-gallon bucket of joint chemical compound. It does make the compound proceed thinner just it is also harder to handle. If you are new at the game, nosotros recommend against it.

Using the widest drywall chemical compound knife you can handle (we use a 12" knife, some hearty souls use a 14" knife) start at the pinnacle of the wall and apply a thin layer (about 1/8") of drywall compound to the wall. Immediately skim the backlog mud from the surface and return it to your mud pan or hawk. Hold the knife at about a 30^° angle and press down fairly hard. The final result should be a thin, ane/sixteen" or and then, coat.

Endeavour to go as smoothen a wall as you can. But, if you get a few tool ridges, don't worry, we volition knock those down later. Keep your pocketknife clean by scraping it oftentimes on the edge of the mud pan or hawk. "A make clean knife for a make clean job" – something apprentice mudders hear over and over and over…

If the section to be skimmed is big – most of a wall, for case, work in manageable swaths. Offset at the ceiling and skim down vertically to only above the centre of the wall. And so piece of work horizontally in about 3-foot sections across the wall. Finally, skim from the bottom of the wall up to overlap the heart section you lot just finished. These are the easiest motions for virtually people to make without excessive fatigue.

When you finish this glaze, clean upwardly, launder your tools and wait 24 hours before applying the final glaze.

Starting time your terminal coat past first scraping downwardly any ridges in your commencement glaze with your drywall knife. Go the surface a smoothen as you can. If there are a lot of ripples, bumps, or other protrusions, you might need to use a sanding block or pole sander to go over information technology lightly. "How to Sand Joint Compound" below for the right sanding technique.

The second glaze is a echo of the first and practical in the same way just thinner. It just fills in any low spots left by the first coat, then y'all don't need information technology very thick. Put in on very, very thin – nigh the thickness of a piece of newspaper. The thin glaze is will not leave whatsoever knife ridges. If it does, your coat is besides thick. Put more than pressure on the knife to thin the coat.

Here y'all might consider thinning the drywall compound with just a niggling h2o to make it easier to utilize a very thin coat. Don't get information technology too sparse. If you do information technology won't stick to your knife. You want information technology about the consistency of cake icing. If you don't know how thick that is, ask your better half to supervise.

The final result should look a lot like the picture above. If you cannot become this effect with two coats, let the second coat cure, then become over it once again with a very, very thin tertiary coat.

Footstep xi Smooth the Plaster

If yous elected to use one of the true plaster topcoats, you can't sand it. It will finish equally difficult as a rock and whatsoever sanding will only disturb that hard skin that forms on the surface of the plaster, and you volition accept to patch it.

Just, we adopt joint compound, and joint compound needs smoothing of some kind. The choices are sanding or burnishing. Let the top coat dry completely – near 24 hours – less if you assistance information technology along with electric fans.

How to Sand Joint Compound Like a Pro

If you decide to sand, utilize a sanding screen (preferred, and available at whatever well-stocked paint store) or 120-grit open-glaze sandpaper and a sanding block or pole sander. A sanding sponge tin be used in place of a block but it's more work. Sanding drywall compound is not difficult merely it is dissimilar from sanding wood. Here are the rules:

1. Less sanding is ameliorate than more sanding. Lightly sand the entire patched surface area. Those new to plastering oftentimes try to go the wall perfectly apartment and fifty-fifty by sanding and more sanding. Yous won't, then don't attempt it. All y'all will do is cutting through the skim coat and have to patch it. Only knock down any projections and go the surface reasonably flat and smooth.

2. Protect yourself and your firm from dust. Wear a mask and comprehend anything you lot do not want to become dusty. Vacuum upwards the dust when yous are done. To reduce drywall grit, you lot tin can rent or hire or purchase a sander in virtually localities that attaches direct to your HEPA shop vac. About ordinary (non-HEPA) vacuums merely shoot the grit dorsum into the air.

iii. Clammy wipe the sanded area. Wipe the whole surface area with a damp cloth or sponge. Damp means "almost dry out". You desire a footling h2o to help pick up the dust merely non enough to dampen the wall finish. Rinse the sponge often. If h2o does not exercise it, endeavour Formula 409 architectural cleaner. Information technology is the but cleaning solution nosotros accept found that picks upwardly drywall grit rather than but spreading information technology around.

The outcome should be a smooth merely dull end wall. Information technology should not have obvious projections or depressions. If it does, do a piffling more sanding on the projections and make full in the depressions, look for the compound to dry, and re-sand the filled areas.

Burnishing For a "Moisture Plaster" Surface

The other end is burnishing. We like burnishing because,

1. it raises no dust and, therefore, makes less of a mess, and

two. in texture and appearance it is virtually indistinguishable from true plaster.

Burnishing is a very unproblematic technique but it is work, and so break out the Bengay for your presently-to-exist sore muscles.

Y'all may non get it all done at once. Since you tin burnish any time before you paint or newspaper the wall, there is no hurry about it.

You will need a spray bottle full of tap water and a 5" or 6" taping knife. If you are applying a decorative finish coat (come across "Burnishing as Decorative Wall Treatment", this page), use a stainless steel knife to avoid leaving rust marks on the wall.

Working about four square anxiety at a time, spray the topcoat until it is damp but no h2o is flowing. Holding the pocketknife at a very low angle, almost apartment against the wall, run it across the damp surface several times in different directions. Use short, very firm strokes. We have a pattern we employ for consistent results: top to bottom, then side to side, then both diagonals, then acme to bottom once more to cease off.

Burnishing compresses the top glaze making it denser, harder and smoother, and gives it a footling sheen.

The difference between burnished and unburnished joint compound is obvious to the touch. Rub your mitt over a burnished area. It will feel difficult, slick, and very polish, just like the gypsum/lime final coat used in true moisture plastering. Run it over an united nations-burnished area for comparing. The raw pinnacle coat will feel rougher and powdery, non nearly as smooth or hard.

A burnished surface looks and feels so much like lime plaster that we have fooled professional plasterers into thinking it was indeed lime plaster.

Now, You're Washed

The wall is ready for your wall end: pigment, wallpaper, or any. Keep in heed that your burnished wall may wait similar real plaster but information technology is simply drywall joint mud, so, if you paint buy the primer for drywall, non plaster.

Congratulations are due. You have just rescued a heritage plaster wall using a plaster-saving technique that works about every time merely that few know about.

Your wall is now as good every bit new simply only to be sure, you lot should inspect it periodically for further cracking – once every 50 years or and then should exist plenty.

You may want to leave the wall unpainted for several weeks. This allows it to dry completely and provides a reasonable interval during which you lot can, graciously and modestly, receive richly-earned accolades from the spouse, kids, neighbors, in-laws, the cable guy, etc.