How to Repair Cracked Plaster Walls Permanently
A cracked plaster wall is normally not an immediate cause for concern but is definitely an eyesore. Despite how scary it may look like, these cracks are easy to repair and can even be done in a day or over the weekend. You can even find inexpensive basic tools and materials needed at your local home improvement store to repair cracked plaster walls
Plaster walls are built architecturally, meaning that they serve no structural purpose whatsoever. This makes them sensitive to movements around the house or other outside stresses.
Therefore, the inevitable settling of the house over time or what we call foundation shifts is the major cause of cracks in plaster walls. Other causes such as inclement weather and impact damages are also noted to cause cracks on plaster walls.
These cracks usually appear above and beside doorways and windows which can be a source of annoying water leaks, especially if it’s exposed outside.
What is a Plaster Wall? Why Would It Need Repair?
Understanding how a plaster wall is built will help you repair cracks more quickly. Generally, plaster walls are built in two layers: the outer plaster and the wood or metal backing called lath. This lath is fixed in its correct layout which is then plastered in large sections using a mortar or any cement-based materials.
That said, your best shot at repairing cracked plaster walls is to preserve the existing plaster instead of ripping it off and plastering it again. Ripping out cracked sections of plaster always ends up in an endless process, with one section leading to another section.
A successful repair means that you should take it slow and apply multiple layers of joint compound — treating it like a simple drywall crack.
Tools and Materials Needed for the Repair of Cracks in Plaster Walls:
- Joint compound
- Sandpaper
- Putty knife
- Joint mesh tape
- Paint primer
- Interior paint
- 6” drywall knife
Repair Guide:
Step 1: V-cut open the crack.
Using your putty knife, v-cut open the crack starting at the edges. While this may seem counterintuitive, increasing the area of the crack is required so that the joint compound will adhere properly. Be gentle and work around the edges until the whole length of the crack is opened.
Step 2: Cut the joint mesh tape.
Cut the joint mesh tape that fits over the length of the crack. One length of joint mesh type is ideal to avoid creating creases, bumps, or folds. But if it can’t be helped, cut to a minimum as much as possible. Joint compound dries quickly so cutting the tape in advance gives you more leeway in working around the cracks.
Step 3: Apply the joint compound.
Prepare the joint compound as per manufacturer’s recommendation. Using your putty knife or 6” drywall knife, apply a thin first coat of joint compound over the crack.
Step 4: Install joint mesh tape.
Using your 6” drywall knife, press the tape over the joint compound. Make sure that the tape is bound between the crack and joint compound. Smoothen the tape just once or twice because too much knife-work can tear the tape.
Step 5: Apply additional joint compound over the tape.
Apply another layer of joint compound. Spread evenly using your putty knife or 6” drywall knife.
Step 6: Lightly sand the joint compound.
Using your sandpaper, smoothen visible bumps or creases lightly. Be modest with your sand-work to avoid sanding deep enough.
Step 7: Finish the crack.
Add a third and final layer of joint compound. This time, extend the spread even farther from the crack and let it dry completely. Slightly sand again to smooth out any uneven surface.
Step 8: Clean the surface by wiping it with a damp cloth.
Step 9: Apply paint primer.
Step 10: Paint accordingly.
Final Word:
At this point, your cracked plaster wall now looks like a brand new wall — absent of annoying leaks and unsightly cracks. Just remember that a cracked plaster wall is non-structural, meaning that it can be repaired using basic methods such as the guide discussed above.
But due to the worrying sights of cracks, the average homeowner might consider treating it as if it is a structural crack. But since plaster walls are built architecturally, it can be repaired using basic methods with the same effectiveness that are significantly less expensive.
If you have further questions regarding how to repair a cracked plaster wall permanently, don’t hesitate to give us a call at Affordable Structural Builders. We are a structural repair company in the Liverpool City Region. We can fix any type of structural defects imaginable at competitive prices! Contact us for free quotes.