I am often called to repair plaster work in older homes. Typically, it'due south to repair a cracked ceiling or areas of walls or ceilings where significant reworking of the plumbing or other mechanicals has been done. I've developed some efficient strategies for both situations that don't require rocking over or demolishing the entire surface.

A drain pipe that had been relocated into the wall cavity couldn't be pushed back far enough and stuck out beyond the plane of the existing plaster surface.
A drain pipe that had been relocated into the wall crenel couldn't exist pushed dorsum far enough and stuck out across the plane of the existing plaster surface.

Large Wall Repair

A hard repair I did on a customer's plaster wall last summer provides a great example. Some major plumbing renovations had required opening upwards the wall and demolishing a big section of plaster. On top of that, a bleed pipage that had been relocated into the wall cavity couldn't be pushed back far enough and stuck out beyond the plane of the existing plaster surface. In this case, as it often is, the door casing and baseboard needed to be left in place, and I wouldn't be able to build upward the plaster or joint compound to be besides thick forth the edges of the trim. All of this meant that I couldn't easily cover the wall section with board cloth, so I opted for using metal lath instead.

Nosotros settled for having the inside corner of the room just a few degrees out of square. To brand that work, I began by ripping a piece of two-by and installing information technology even with the airplane of the pipe to create a solid attachment for metal lath, which I could then roll out from the corner 2x2 over the drain pipe, and blend into the casing.

Then I covered it with wire lath, securing the lath with screws and plaster washers.
And then I covered it with wire lath, securing the lath with screws and plaster washers.

Material and lath. In previous repairs, I had discovered the use of plaster over wire lath that had been backed with rosin paper to help prevent also much plaster from falling through the lath. Instead of rosin newspaper, I used FibaFuse Wall Reinforcement fabric, which I use regularly for resurfacing ceilings, as I will explain later in this article. For the wall repair, I stapled the textile over the opening in the wall, and so covered it with wire board, securing the lath with screws and plaster washers. As luck would take it, the opening I was repairing could be covered with a single canvass of board measuring 8 anxiety by 27 inches—a mutual size for wire lath.

Primer and base glaze. Before applying the plaster over the mesh and ceiling repair, I beginning had to apply a plaster bonding agent. In add-on to helping the plaster bond to a variety of materials, the bonding agent reduces the water assimilation out of the plaster, allowing the plaster to cure properly.

I mixed the base-coat plaster to a thick consistency, and I started applying the plaster along the lesser of the wall. Because I used a thick mix, started along the lesser, and had the material behind the board, I was able to build upwards the plaster to a thickness of at least 1/2 inch and taper it to zippo along the casing. When I returned the next mean solar day, the plaster had ready into a solid surface. The alloy-in over the drain pipe already looked good.

For the next coat, I applied a thick coat of setting chemical compound, which set up in about an hour. I and so applied a thin coat of lightweight joint chemical compound for the final coat. This coat was merely a skim coat of compound to smooth and make full in any remaining defects in the surface. When it was dry out, I sanded it to a smooth finish with 220-grit sandpaper.

I then applied a thin coat of lightweight joint compound for the final coat.
I then practical a thin coat of lightweight joint compound for the final coat.

Repairing Ceilings

Large ceiling areas can exist repaired with pieces of drywall. On this job, an area of the ceiling above the wall repair had besides been demolished, by the aforementioned plumber who installed the drainpipe. The plaster and lath was well-nigh one inch thick, so I padded out the ceiling joists with strips of 1/two-inch drywall earlier installing large pieces of the same material to fill up in the hole. Notation that the plaster around the perimeter should be well secured with screws and plaster washers, and any pocket-sized areas of exposed board should too be secured.

The plaster and lath was about one inch thick, so I padded out the ceiling joists with strips of 1/2-inch drywall.
The plaster and lath was most one inch thick, and so I padded out the ceiling joists with strips of 1/two-inch drywall.

Regular drywall tin be used as a plaster base, but it—and whatsoever exposed wood board you want to plaster over—must be treated with a bonding amanuensis. Next, I prefill any open joints and the perimeter of the patch with base-coat plaster (10), into which I embed fiberglass tape. When that has ready, I follow with a coat of setting compound and plume in the patch before resurfacing the rest of the ceiling.

Resurfacing Plaster Ceilings

Many old plaster ceilings have shallow cracks over much of the surface, and it'south time-consuming to employ record over every crack fifty-fifty when yous're using cocky-agglutinative mesh tape. And then all those taped areas have to exist concealed with multiple layers of compound. This is before the spider cracks are even considered.

Spider cracks are what I call the fine cracks that are sometimes all over an one-time plaster ceiling. They appear to just exist cracks in the paint, but I was never sure what to do about them. Was it necessary to reinforce each one? Doing that would be hard and time-consuming and crave a lot of mesh tape.

Prep work. You're finishing over an existing surface, so if information technology's in poor condition, any material applied over it volition exist compromised. If the base is loose, muddied, or too absorbent, or if it offers poor adhesion or has some other problem, then the new surface may not create the stable, durable terminate desired.

To prep the existing surface, I remove any loose plaster or paint and seal any watermarks or stained areas of the ceiling. Frequently, areas of the ceiling will have separated from the lath, typically considering the keys into the wood lath have cleaved. These areas tin can be pulled in tight to the board by using plaster washers.

Areas that are recessed or crowned should be filled or feathered out at this time with a setting compound.
Areas that are recessed or crowned should be filled or feathered out at this time with a setting chemical compound.

If the surface is very smooth, first rough information technology upward with a coarse-grit paper (lxxx grit or coarser). On glossy painted surfaces, I accept used paint de-glossers with success, but using a plaster bonding agent, such as Plaster-Weld, is my preferred method.

I advise 5-grooving larger cracks, and so filling them with setting chemical compound and roofing them with extra-strength fiberglass mesh tape. Areas that are recessed or crowned should be filled or feathered out at this time with a setting compound. Using the setting compound allows me to complete the prep work and motility right on to embedding the glass mat I programme on using to reinforce the unabridged ceiling.

Tip: Prior to starting a chore, you should prep a test expanse to make sure that the method yous are thinking of using is going to work. That way, when you start the work, yous can feel confident that yous will have proficient adhesion.

My preferred method for applying the joint compound is using a paint roller that has a 1/2-inch nap cover.
My preferred method for applying the joint chemical compound is using a paint roller that has a 1/two-inch nap cover.

Resurfacing. To achieve a new, smooth ceiling surface over quondam plaster, I begin by blanket the ceiling with a sparse layer of joint compound. This acts every bit an agglutinative for a fiberglass mat, which serves equally a reinforcement to bind small-scale cracks together and create a new, even surface.

My preferred method for applying the articulation compound is using a paint roller that has a one/2-inch nap cover. The skim coat could as well be practical with a wide taping pocketknife or even with a paint sprayer capable of spraying articulation compound. The compound thickness should be almost one/viii inch (3mm). Edges close to walls and ceilings tin be coated by applying the compound with a paint brush or taping knife.

I propose using a heavy-weight all-purpose compound, rather than a lighter-weight compound, because of its greater strength and adhesion qualities.

The reinforcing mat I use, FibaFuse Wall Reinforcement, is a cobweb­drinking glass mat (not a weave), and because the fibers are not especially dumbo, it is quite porous. And so it'south like shooting fish in a barrel to embed in articulation compound, which is the adhesive that holds the material in place.

Position the first piece of wall reinforcement along a straight corner or chalked line and press it into the compound with a wide taping knife, working from the center toward the edges.
Position the first piece of wall reinforcement along a straight corner or chalked line and press information technology into the chemical compound with a wide taping knife, working from the heart toward the edges.

You should span the entire ceiling with i length. (On a wall, the mat should be hung vertically every bit 1 length, as well.) Position the start piece of wall reinforcement along a direct corner or chalked line and printing it into the compound with a wide taping knife, working from the middle toward the edges.

Each adjacent piece of the fiberglass mat is butted to the prior piece. This method is preferred, and I do information technology by first snapping a series chalk lines at intervals the width of the FibaFuse curl. Because the mat is relatively thin, it can as well exist lapped and double-cut, every bit you might practice with wallpaper. Double-cutting is when you cutting through both layers with a utility knife then remove the narrow strips, leaving tight-fitting butted edges.

Excess material along the edges and around cased openings gets cut off with a taping pocketknife. The fiberglass mat cuts easily, and then at that place's no demand to use a sharp pocketknife. Continue to embed tightly with the taping knife until the mat is smooth and compound is forced through the face.

Within a few minutes of embedding one length of the fiberglass fabric into the compound, apply a second coat of the same joint compound, rolling it on and working it firmly into the surface.
Inside a few minutes of embedding 1 length of the fiberglass textile into the compound, utilize a second coat of the same articulation compound, rolling it on and working information technology firmly into the surface.
After sanding the base coat, roll on more joint compound.
After sanding the base of operations coat, roll on more joint compound.

Work one length at a time. Within a few minutes of embedding one length of the fiberglass fabric into the compound, apply a second coat of the aforementioned joint compound, rolling it on and working it firmly into the surface. This process fills any voids in the surface and any dry areas behind the fiberglass mat. Immediately polish and remove nearly of this layer of compound with a wide taping knife, leaving only a sparse coat of compound over the surface.

Let the compound dry out thoroughly—it will about likely take more than 24 hours. At that indicate, lightly sand with a fine, 220-dust sandpaper.

Remove and smooth with a wide taping knife, leaving the surface smooth and tight.
Remove and smooth with a broad taping knife, leaving the surface smooth and tight.

Coat again. After sanding the base glaze, ringlet on more than joint compound. (A lightweight compound can be used for this final awarding). Remove and smoothen with a broad taping pocketknife, leaving the surface smooth and tight. This process is similar to applying a Level 5 cease (run into "Specifying Drywall Finishes," Nov/09). In most cases, no additional sanding is needed.

Photos by Chris Ermides