In my parents’ old house, they had in incredible master suite consisting of a large bedroom with two closets, one an enormous walk-in that we concluded must have once served as a nursery, as it had a second door that opened on the hallway, an even larger sitting room/office that featured a big bay window, built-in bookshelves, and a wood burning stove, and bathroom. The sitting room was particularly popular in winter: the stove provided incredible warmth, and it was just a wonderfully cozy, peaceful place to read or do homework when the weather outside was frightful.
Perhaps it was the drying effect of the stove, but the plaster walls in this room started to crack while I was still in high school. Sometimes he would patch the cracks, and sometimes I would, but all we did was delay the inevitable: new cracks would inevitably appear around the edges of the latest patch. When cracks appear, it often signals the beginning of the end for a plaster wall.
Why? Well, let me explain plaster by talking about concrete. If you look at your driveway or a sidewalk, you will notice that it appears to be made of large, rectangular concrete blocks. But have you ever seen one of those “blocks” laid down? Of course not. Concrete is poured, and then the seams are cut into it. These seams allow each section to expand and contract without cracking, and prevent cracks in one section from spreading to others.
Plaster is similarly rigid, only it doesn’t have seams cut into it like concrete does. Unlike a wall made of drywall, which consists of several separate components, a plaster wall is a single unit, and when it starts to crack, this can indicate that the entire unit is starting to fail. But not always.
In the case of my parents’ sitting room, we eventually gave up. My brother-in-law Hans and I offered to help remove the plaster and replace it with drywall, and we spent a full day doing demolition. Then my dad spent several days putting up the drywall, and the rest of his life giving Hans and I grief for underdelivering on our promise.
If you’ve got a plaster wall that’s starting to crack, in most cases you’ll want to start by repairing it. One consequence of the repair process is that plaster around the crack that is stressed will break loose, and sometimes this is enough to prevent further damage to the wall. But if there are multiple cracks in the wall, or if new cracks continue to appear, what’s probably happening is that, over time, the stress points on the wall have changed, and this new stress is causing the entire plaster wall to fail. When this happens, it’s probably time to consider replacing the plaster with drywall, which is much easier than making endless repairs, or installing new plaster.