The next thing I want to bring up is some of the common problems that occur with plaster both in older and newer homes. It’s important to be able to identify the problem so the right diagnosis is given, and that the repair is done correctly. I may have briefly mentioned some of these before, but here’s more of a complete list that I put together:

Map cracking: This is mainly caused by a weak base coat that was initially applied to the wall or ceiling area. Poor setting of the material and oversanding of the mix are some causes of a weakened base coat. Over this the plasterer applies a super-hard finish coat. This surface is very hard, but also brittle. Over the years, settling of the home occurs. Stress on the walls can cause buckling, and the base coat, instead of holding up and remaining rock solid, literally crumbles. You get an indication of such a condition when you start scraping out the cracks to do the repairs. As you scrape, it’s almost like someone opened a bag of sand inside the wall and it comes pouring out of the crack! 

Chip cracking: This has to do with what happens once the plaster is applied to the wall or ceiling. It’s good to keep in mind that with most materials that are used with drywall, a “physical” set occurs, basically meaning that it air dries. 

Plaster, on the other hand, is a “chemical” set material, meaning that the wet plaster goes back to its original state of rock. The “set time” may span from just a few minutes on highly gauged mixes, to several hours on fresh and slow setting gauges. 

So picture this: A plasterer comes into a home and applies a scratch coat and thick base coat over a room. He comes back the next day, or maybe later, and applies a smooth finish coat over the very dry surface. Next, he applies the plaster, water trowels it and leaves. However, the dry base coat starts absorbing a lot of the moisture out of the finish coat. If there is any type of delay in the finish coat’s “chemical” set (returning to a rock-solid state), chip cracking will occur. 

It’s like wet mud alongside the road. Suddenly the sun comes out super hot after a rain and boom! The moisture is sucked out of the mud ultra fast and it cracks up big time. Something similar can occur with plaster. You have a thin wet layer of mud spread over a “hot” base coat. “Hot” meaning super dry so that it pulls the moisture out of that finish coat being spread over it really quick. 

The result: Areas of the plaster looking like little “chips” of paint all in a cluster together (like that mud); sometimes appearing very faint and in isolated spots, and other times very pronounced and covering an entire wall or ceiling.

This definitely has a weakening effect on the finish coat. Photo #1 shows the effects of chip cracking. The area on the wall and ceiling above this doorway dried out too quickly and literally flaked off from light scraping with a margin trowel.

Bulging: This is a condition that is often misdiagnosed as water damage by many a claim adjuster. It occurs most often on the wall area. I often find this condition in kitchens, bathrooms and other places where there is a lot of humidity. 

It can show up anywhere really, and can be just an inch out from the surrounding wall surface to several inches out. It can cover an area several feet wide and high. I’ve usually found bulges like this mostly in isolated “pockets” on the wall, one or two areas in a large room, though I have found some walls that were literally covered by these bulges. 

The underlying base coat is usually in a fine, solid condition. Bulging can also be caused by downward pressure from a house settling. I once fixed a large bulge on the back part of the home where the foundation had given way an inch or two, just enough to cause the inside plaster to buckle up. These problems are found in older, historic homes, usually with wood lath and three-coat plaster.
Stress and vibration: Cracks in older and newer homes are prone to have stress cracks over doorways, on each side of windows (above and below) and on outside walls where heavy traffic on the street causes hairline cracks to occur frequently. 

Cracks around staircases are often caused by vibration from the traffic going up and down over the years. Cracks also appear across ceilings that have insufficient support, or that may have stress on them from above (furniture and heavy-duty stuff stored in an attic over a ceiling). 

While I’m on the subject, there is one, shall we say, preventable type of crack that I see all too often. It’s caused by what you see in photo #2. 

I came into this home and found the drywall corner bead attached just as you see it. How many screws do you count in the bead? This thing was flapping while I was looking at it! Whoever installed the beads was either in a hurry or trying to save money in the wrong place. 

I recently troubleshot a house for a couple. They just bought the home and it was half drywall, half plaster. Would you believe that every bead that was on an outside corner had hairline cracks running the whole length, from top to bottom? 

I chipped away the mud on four of them just to see what was up. It was just as I had imagined. On one bead they had put screws about every 2 1/2 feet. The worst was 3 feet apart. In all, each bead had about eight screws holding it in place. 

The other place notorious for “cracking out” is around a stairway, the bead around the opening that leads upstairs. If the individuals who were installing these beads weren’t moving like they were “killing snakes,” and would just put a little more quality into the job, maybe there wouldn’t be as many repairs like this. Oh, well. I’m not out to change the world on this one. Just an observation. It’s a fact, though, that a great living could be made just by doing repair beads!

Paper chase: At least that’s what I call this one. It’s where the contractor or someone in charge of the finishing process decides not to size or prime the wall before wallpapering. The paper is hung over a drywall-finished wall area. 

A few years pass, and someone decides to remove the old paper and re-decorate. Surprise! Photo #3 shows the results. Of course as water is applied to the wallpaper to remove it (or sometimes just pulling it off), the top layer of the wallboard comes with it, leaving a brown paper behind. This repair is quickly gaining on the corner bead problem in the standings! And it’s not always easy to fix. We’ll talk about some solutions to this one and the others mentioned soon.
Nail pops: These show up along the edges of the ceiling, many times several nails popping in a row. The reasons include movement of the board itself, incorrect installation of the nail or screw, or pressure exerted from the joist that it is attached to.

These are small but unsightly problems, and have been the direct reason some homes put on the market would not sell until this problem was fixed.

Radiant heat ceiling: For some reason I have been hitting a string of these types of ceilings and the disasters that they can cause. The heat source is attached to the board when first installed, and plaster is used to “bed in” the coils or wires. The problem I’m seeing today is that the 1 1/4-inch nails that were used to hold the board up are giving way. 

I don’t think this is an isolated case, either. I think we’re getting to the 15-year mark on some of these installations, and it seems that this type of ceiling is failing at a more and more frequent rate. The sad thing to me is that when one of them does come down, usually the homeowner policy does not cover it. I just met with one adjuster here recently and they ruled it “faulty workmanship”… from 16 years ago. 

Finish coat separation: Photo #4 gives an example of this. In many cases insurance will cover this one, especially if the leak or water that came through was “sudden and accidental,” the term insurance companies use. 

It takes in storm damage where part of a roof comes off and the resultant water that comes in damages the ceilings and walls. It also covers tub overflows and frozen pipes that suddenly burst. Photo #4 was an example of a pipe that burst and ruined the ceiling above, causing the finish coat to separate on the wall area.

Falling plaster: I’ve mentioned before that if a ceiling gets wet, especially in the case of wood lath and three-coat plaster, the damage is not always apparent right away. Sometimes several months or even a year later, I’ve been called in to repair ceilings where large chunks of plaster fell down. 

What has happened is the water comes through and the wood lath gets wet and warps a little, causing the plaster “keys” to break. The sheer weight of the plaster will eventually cause a piece to develop a hairline crack around it that can usually be seen well before it falls. If not given attention, the piece will suddenly fall. This type of repair is usually covered by insurance as well, under the “sudden and accidental” term. 

Next up, we’ll discuss how to tackle some of these problems and some step-by-step techniques for solving them. It should prove helpful in putting these “Humpty Dumpty” projects back together again!

If you have any other types of problems that you need help on, drop me a line. Better yet, send me a picture. Each repair is unique, as are many of the textures that have been and are being applied to walls and ceilings. 

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