Don’t worry about cracking under pressure—plaster walls aren’t a difficult fix
If you see cracks in your plaster wall, your first thought should be, “How do I fix it?” While cracks in plaster walls aren’t as serious as cracks in your brick, you shouldn’t wait to address them. Cracks in plaster can spread and quickly run the entire length or height of your wall.
Once you determine that the crack is merely an aesthetic nuisance, and nothing more serious, follow the steps below to bring your cracked wall back to its former glory.
Most plaster cracks are purely cosmetic. However, if your foundation shifts or you experience severe weather such as a hurricane or earthquake, a large crack can be a sign of more substantial damage. If you aren’t sure which one, it’s best to call a local plaster repair professional.
It’s obvious why you should fix serious cracks, but what about the aesthetic ones? While not as consequential, smaller cracks become visually unappealing if left unfilled. This affects both your home’s value and over time, as it spreads, could actually become a more serious type of crack. It’s best to fix it early.
Fixing cracks shouldn’t take more than a day or two. The step that takes the longest is usually waiting for the compound to dry. In terms of absolute work, it shouldn’t take more than a few hours. Just follow the steps below and make sure you take your time because if you make a mistake, you’ll likely have to retrace some steps.
This may seem strange, but the first thing you need to do is actually widen the crack. Remove any damaged pieces first, and then, with a utility knife—some use a putty spreader—run the sharp edge along the inside of the crack. You have to do this so there is a clean and uniform depression for the joint compound to adhere to. It’s normal that this makes a mess, so tape some plastic drop sheets to the ground under your workspace.
Also called drywall tape, plastering tape is a self-adhesive fiberglass mesh tape. It looks like squared-off fish netting or medical gauze and is usually about four inches wide. It isn’t the cheapest tape to buy, but it is meant to strengthen the joint compound like steel cables strengthen concrete bridges. Smaller fixes will require you to patch the plaster. Run your tape along the entirety of the crack, extending it at least two inches past the crack to increase adhesion.
You will be using joint compound, also called drywall repair, plaster repair, or plaster compound. It comes in small, yogurt-sized containers. Using a flexible putty knife, spread a thick layer on top of the tape that covers the crack. Follow the instructions for drying, which usually requires an overnight cure. Important: read the safety warnings. Some repair compounds require ventilation.
Use a finer grit sandpaper. 120-220 grit works well. You’ll want to very lightly sand the compound on top of the crack. Be gentle because you don’t want to damage the surrounding wall or the tape underneath. Sand just until you can barely make out the plaster tape. At this point, the wall should appear uniformly flat to the naked eye.
Feathering out even further from the tape, spread a much thinner layer than the first. You want to just cover the tape. Think of your first layer of compound as your structural layer, and your second as your aesthetic layer. Take your time to spread it evenly, as sanding it to an even depth will be much easier. Let this layer dry and cure as well before you start sanding.
Sand the second layer of compound much like you did the first. If you have higher grit sandpaper (the higher the number the finer the grain) use it here. Sanding the second layer can be akin to polishing the work you’ve done up to this point. Use slow, circular motions and try not to apply too much pressure.
This is a step many skip but we consider it to be an important one. Run your hand along the cured compound that you’ve sanded. You should feel no bumps or deformities. Other than the texture, the compound should feel just as flat as the wall surrounding it.
Try holding a flashlight against the wall and shining it toward the compound—if you see any shadow, this means the compound is protruding from the wall. Sand as much as you can without getting to the tape or damaging the wall around it.
Once the area has been wiped with a dry cloth to remove any particles left from sanding, you can paint over the fixed plaster. This will take multiple coats, and you’ll want to paint a bit further out from the crack than where the compound ends. This can help the newly painted area blend into the existing wall. If you haven’t painted in a while or the wall is dirty, you may need to paint the entire wall.
Newly plastered walls will require a primer as the surface won’t allow for paint to adhere easily. However, since you’re fixing a crack and will be painting over the joint compound, you don’t need to prime the wall. There should be paint already on top of the plaster, and you can paint right on top.
It isn’t easy to prevent a plaster wall from cracking. The below reasons are common causes of plaster cracks:
House foundation shifting
Overly moist or dry environment
Weak walls that lack support
Concussive force applied to the wall (i.e., banging heavy furniture against it)
One of the easiest ways to prevent plaster from cracking is to make sure your interior temperature and humidity are within normal ranges and don’t experience wild swings. Plaster doesn’t like pronounced swings in the environment, and will eventually start cracking or peeling.
The other two ways to prevent cracking is to be careful around the wall with heavy objects. Don’t hammer anything too hard into the wall and if you are rearranging furniture, try not to slam it against the wall. The last and by far most expensive preventative method is inspecting your foundation.
For the purpose of this article, we’re going to assume your crack isn’t a serious issue that requires any foundation work. Plaster professionals will charge anywhere from $60 to $80 per hour to repair a plaster wall. There may also be the cost of materials, but that will be shared with the DIY cost.
If you feel you can fix the crack yourself, expect to spend a few hours of time and somewhere around $50 to $80 total. You will need the repair compound, a putty spreader, plaster tape, and sandpaper. DIYing a cracked plaster wall is a fairly easy process, and is something those with plaster walls should learn how to do to lessen the cost of fixing future cracks.
Old plaster walls usually crack because of changes in temperature and moisture over a long period of time. Structural changes like a shifting foundation—even a tiny amount of movement—can affect a plaster wall, causing it to crack. This last reason may seem obvious, but materials don’t last forever, and a plaster wall can simply degrade over time from age alone.
Generally, homeowners insurance will only cover cracks in walls if the cracks were caused by a specific type of damage covered by your policy, such as a burst pipe or hurricane-force winds flexing your walls. Every policy is different so you’ll need to read your policy before assuming a crack is covered just because it’s part of your home.
Wide cracks, horizontal or stair-step cracks, or cracks near structural areas like door frames can all be signs of foundation issues. If your house is new and a crack is minor, remember that houses tend to “settle” for the first few seasons and it usually isn’t something to worry about. If the cracks are wider than a pen or pencil, or you can stick more than three stacked credit cards into them, it’s time to call a professional.
Drywall is cheaper—period. It is less per square foot, labor is cheaper because it requires less specialization, and the materials are cheaper. Most people handy with a drill and sandpaper can drywall without much fuss as well, so you can save money on the cost of professional labor if you DIY a drywall project (like redoing the walls in a basement or garage).
Plaster walls are more expensive than drywall, but can be cheaper than other wall options like stone or tile. Those considering plaster over drywall will need to decide whether the aesthetic and future repair costs are worth the upgrade. For many, plaster walls have a certain look that is worth the cost and work of repairs and maintenance.
