Understanding Why Walls Crack
Before you start fixing a cracked house wall, it’s crucial to understand the potential reasons behind the cracking. This understanding can help you assess the severity and choose the correct repair method. Cracks are rarely random; they are usually symptoms of underlying forces acting on the wall material.
Common causes include the natural settling of the house’s foundation over time. As the structure adjusts, minor stresses can cause plaster or drywall to crack. Temperature and humidity changes cause building materials to expand and contract, leading to small cracks, especially around openings like doors and windows. Poorly applied drywall tape or insufficient joint compound during initial construction can also result in cracks appearing later.
Assessing the Severity of the Crack
Not all cracks are created equal. A key part of Fixing a Cracked House Wall: A Complete Guide is learning how to assess the damage to determine if it’s a simple DIY fix or a sign of a more significant problem requiring professional help. Look closely at the size, shape, and location of the crack.
Hairline Cracks
These are the most common type of crack, often no wider than a credit card. They are usually just surface-level cracks in the paint, plaster, or drywall compound. Hairline cracks are almost always cosmetic and are typically easy for a homeowner to repair.
They often occur due to drying and shrinking of the finish materials. You’ll frequently see them around the corners of windows and doors or along seams in drywall. While unsightly, they rarely indicate any structural concern.
Larger Non-Structural Cracks
These cracks are wider than hairline cracks, perhaps up to 1/4 inch, but do not show other signs of structural distress. They might run horizontally or vertically and can be caused by slightly more significant settling or fluctuations. While still considered non-structural in many cases, they require a more robust repair method than simple spackling.
These cracks might need to be taped and mudded like a drywall seam. Monitoring these cracks over time is wise; if they grow rapidly or widen significantly, reassess the situation.
Structural Cracks
These are the cracks that warrant immediate attention and likely professional assessment. Signs of structural issues include cracks wider than 1/4 inch, especially if they are jagged, follow a stair-step pattern in brickwork, or appear near foundation issues. Cracks that are constantly widening or growing quickly are also red flags.
Look for cracks that extend from the wall to the ceiling or floor, or those accompanied by other issues like sagging floors, sticking doors or windows, or bulging walls. Fixing a Cracked House Wall that involves structural damage is beyond the scope of typical DIY and requires a qualified structural engineer or contractor.
Gathering Your Tools and Materials
Once you’ve assessed the crack and determined it’s a non-structural issue you can tackle yourself, the next step in Fixing a Cracked House Wall: A Complete Guide is gathering the necessary supplies. The specific items you need will depend on the size and type of crack you are repairing.
For Small, Hairline Cracks
Repairing minor cracks is straightforward and requires only a few basic items. This is the easiest type of cracked house wall repair.
- Materials:
- Spackle or Lightweight Joint Compound: Suitable for filling narrow gaps.
- Sandpaper: Medium-grit (120-150) for smoothing.
- Primer: To seal the repaired area before painting.
- Paint: To match the surrounding wall color.
- Tools:
- Putty Knife: Small size (1-2 inches) for applying spackle.
- Dust Mask and Safety Glasses: For protection during sanding.
- Drop Cloth or Plastic Sheeting: To protect the floor and furniture.
For Larger Non-Structural Cracks
These repairs are more involved and require materials designed for bridging wider gaps and preventing cracks from recurring. This is where the full detail of Fixing a Cracked House Wall starts to unfold.
- Materials:
- Setting-Type Joint Compound (“Hot Mud”): Dries harder and faster than regular compound, good for filling deeper cracks. Choose a setting time (e.g., 5, 20, 45, 90 minutes).
- All-Purpose or Lightweight Joint Compound: Used for subsequent coats to achieve a smooth finish.
- Drywall Tape: Either paper tape (stronger but trickier to apply) or fiberglass mesh tape (self-adhesive, easier for DIY). Mesh tape is often preferred for wall cracks.
- Sandpaper: Various grits (120, 150, 220) for progressive smoothing.
- Primer: Crucial for sealing the repaired area.
- Paint: Matching your wall color.
- Tools:
- Utility Knife or Crack Scraper: To clean out the crack.
- Putty Knives/Joint Knives: Several sizes are helpful (e.g., 4-inch, 6-inch, 10-inch) for applying compound and feathering.
- Mud Pan: For holding joint compound.
- Dust Mask and Safety Glasses: Absolutely essential for protection from dust.
- Drop Cloth or Plastic Sheeting: For extensive floor protection.
- Sanding Block or Pole Sander: For easier and more even sanding.
- Clean Rags or Sponge: For cleaning.
Additional Considerations
Ensure you have adequate ventilation when working with joint compound dust. A fan blowing outwards through a window is a good idea. Having a vacuum with a HEPA filter nearby can also help manage dust during sanding.
Step-by-Step Guide to Fixing Cracks
With your tools and materials ready, you can now proceed with Fixing a Cracked House Wall. The process differs slightly depending on the size of the crack. Always start by protecting your work area with drop cloths.
Fixing Small, Hairline Cracks
This is the simplest repair outlined in Fixing a Cracked House Wall: A Complete Guide.
- Clean the Area: Use a dry cloth or brush to remove any dust, cobwebs, or loose paint from and around the crack. Ensure the surface is clean and dry.
- Fill the Crack: Using a small putty knife, apply a small amount of spackle or lightweight joint compound directly into the crack. Hold the knife at a slight angle and force the compound into the gap.
- Smooth the Surface: Scrape off any excess compound, leaving just enough to fill the crack flush with the wall surface. Use the putty knife to smooth it out.
- Let Dry: Allow the compound to dry completely. Drying time varies depending on humidity and thickness, but usually takes 1-2 hours for spackle. Check the product instructions.
- Sand Smooth: Once dry, lightly sand the repaired area using fine-grit sandpaper (150 or 220). Use a sanding block for even pressure. Sand just enough to make the patch flush and smooth with the surrounding wall.
- Clean Dust: Wipe away the sanding dust with a damp cloth.
- Prime: Apply a small amount of primer over the patched area. This seals the compound and helps the paint adhere evenly, preventing dull spots. Let the primer dry.
- Paint: Apply one or two coats of paint, matching your wall color. Allow drying time between coats as per paint instructions.
Fixing Larger Non-Structural Cracks
Repairing wider cracks requires more steps and materials to ensure a strong, lasting repair. This section is a core part of Fixing a Cracked House Wall: A Complete Guide.
- Prepare the Crack: Use a utility knife or crack scraper to widen the crack slightly into a V-shape. This helps the joint compound get deeper and bond better. Be careful not to cut too deep. Remove any loose plaster, paint, or drywall paper. Brush away all dust and debris. The crack must be clean for the tape and compound to adhere properly.
- Apply Joint Compound (First Coat): Mix your setting-type joint compound according to the manufacturer’s instructions. Using a 4 or 6-inch joint knife, apply a thin layer of compound directly into the V-groove you created. Ensure the crack is completely filled.
- Embed the Tape: While the compound is still wet, carefully center your fiberglass mesh tape over the crack and press it firmly into the wet compound using your joint knife. Ensure there are no bubbles or wrinkles. If using paper tape, fold it along the crack line and press it into the wet compound, then immediately apply a thin coat of compound over the tape to fully embed it.
- Apply Second Coat (Over Tape): Immediately apply a thin, even coat of setting-type compound over the embedded tape, extending it about 2-3 inches beyond the edges of the tape on both sides. Use a wider knife (e.g., 6-inch) for this. This is often called the “fill coat.”
- Let Dry: Allow the setting-type compound to dry completely. The setting time is on the package (e.g., 20 minutes), but full drying may take longer depending on humidity. It will change color when dry.
- Apply Third Coat (Feathering): Once the first coat over the tape is dry, apply a second, slightly wider coat using an all-purpose or lightweight compound and a wider knife (e.g., 10-inch). Feather the edges by applying pressure to the knife edge furthest from the center of the patch. This helps the patch blend seamlessly into the wall. Extend this coat about 6-8 inches beyond the center of the crack.
- Let Dry: Allow the third coat to dry completely (usually several hours or overnight for all-purpose compound). It must be fully dry before sanding.
- Apply Fourth Coat (Optional Finishing Coat): If needed, apply a very thin final coat using lightweight compound and your widest knife (or a finishing knife) to fill any imperfections or achieve a smoother transition. Feather the edges widely.
- Let Dry: Allow the final coat to dry completely.
- Sand Smooth: Once all coats are completely dry, sand the patched area. Start with 120-grit sandpaper to remove any high spots or ridges. Then progress to 150 or 220-grit for a smooth finish. Use a sanding block or pole sander and sand in circular motions or long strokes, feathering the edges into the existing wall surface. Wear your dust mask and safety glasses!
- Clean Dust: Thoroughly wipe down the wall to remove all sanding dust. A slightly damp sponge works well, followed by a dry cloth.
- Prime: Apply a quality primer over the entire patched area. Primer seals the porous joint compound and ensures uniform paint absorption. Without primer, the patch will look dull compared to the surrounding wall. Let the primer dry according to instructions.
- Paint: Apply at least two coats of paint, allowing sufficient drying time between coats. You may need to paint the entire wall or even the entire room for the color to blend perfectly, especially if the original paint is older or the wall is large.
Tips for a Professional Finish
- Use thin coats of joint compound rather than one thick one. Thin coats dry faster and are less likely to crack or shrink.
- Clean your tools frequently while working. Dried compound is difficult to remove.
- Don’t over-sand. You want a smooth transition, not a depression in the wall.
- Hold a light source (like a work light or even your phone’s flashlight) parallel to the wall to check for imperfections (high or low spots) before and after sanding.
Knowing When to Call a Professional
While this guide provides comprehensive steps for Fixing a Cracked House Wall for many common issues, it’s crucial to recognize your limitations and the signs of more serious problems. Attempting to fix a structural crack yourself is not only ineffective but can potentially worsen the situation.
If you observe any of the following, stop your DIY plans and contact a qualified professional, such as a structural engineer or a foundation repair specialist:
- Cracks that are wider than 1/4 inch and run horizontally.
- Cracks that form a stair-step pattern in brick or block walls.
- Cracks that appear on exterior walls alongside interior cracks in the same location.
- Cracks accompanied by other signs of foundation movement, such as sloping floors, sticking doors/windows, or visible shifts in the foundation itself.
- Cracks that grow noticeably larger or wider over a short period (e.g., days or weeks).
- Cracks that appear after a significant event like heavy rain, drought, or nearby construction.
- If you are simply uncomfortable or unsure about the nature of the crack after assessing it.
Investing in a professional assessment for potential structural issues is always wiser and ultimately less expensive than attempting a repair that doesn’t address the root cause.
Conclusion
Fixing a Cracked House Wall: A Complete Guide has aimed to empower you to tackle common wall cracks with confidence. From the simple cosmetic repairs for hairline cracks to the more involved process of taping and mudding larger non-structural fissures, most wall cracks are manageable DIY projects. The key is careful assessment, using the right materials, and patience during the drying and layering process.
Remember that while fixing the visible crack addresses the symptom, understanding the cause is important. If you suspect moisture issues, foundation problems, or significant structural shifts, prioritize calling a professional. For everything else, a little joint compound, tape, sanding, and paint can go a long way in restoring the smooth, flawless finish of your walls. With the steps outlined here, you can effectively undertake the task of Fixing a Cracked House Wall and maintain the beauty and integrity of your home’s interior.
