Cracks in walls are a common problem that most homeowners face at some point. They can occur due to various reasons like settlement of the foundation, shrinking and expansion of construction materials, poor construction quality, etc. While small cracks may seem harmless, if left unattended, they can become larger and lead to further structural damage. Therefore, it is important to find a permanent solution to fix wall cracks and prevent them from reappearing.
What causes cracks in walls?
Settlement and movement
The most common cause of cracks in walls is the settling or movement of the foundation. As the foundation settles over time, it causes the structure above it to settle as well, leading to cracks. Other factors like soil erosion, groundwater depletion, nearby construction activity etc. can also cause foundation movement and lead to cracking.
Shrinkage
Shrinkage of construction materials is another major cause of cracks. Concrete, mortar and even wood can shrink as they dry and set leading to cracks. Plaster and drywall, for example, contain a lot of moisture during installation. As this moisture evaporates, the material shrinks slightly causing cracks.
Thermal expansion and contraction
As temperatures fluctuate, construction materials expand and contract leading to stresses. Over time, this can manifest as cracks. Materials like concrete and mortar are prone to such thermal movements.
Poor construction quality
Use of poor quality materials, improper installation methods, lack of expansion joints etc. can lead to inherent weaknesses in the structure that may crack over time. Even the use of heavyweight materials on top of lightweight framing can cause excessive loads leading to cracks.
Common locations for wall cracks
Some common locations where wall cracks tend to occur frequently include:
Corners of doors and windows
The corners around door and window openings are areas of stress concentration and often develop cracks as the house settles.
Intersection of walls and ceilings
Differential movement between walls and ceilings can cause cracks at their junction. These cracks usually run vertically.
Top of walls near the ceiling
Walls tend to settle more than ceilings resulting in horizontal cracks near the ceiling line. These cracks are typically wider at the center and taper towards the edges.
Center of walls
Long horizontal cracks may appear at the center of long partition walls or exterior walls due to continuous movement causing the drywall or plaster to bend and crack.
Types of cracks
Identifying the type of crack can help ascertain its cause and suitable repair method. Some common types include:
Hairline cracks
These are very thin cracks ranging from 1/64th to 1/16th of an inch. They are commonly caused by minor foundation movement, material shrinkage or thermal expansion/contraction.
Horizontal cracks
Horizontal cracks usually indicate settlement as walls tend to crack from top to bottom. They may run along the ceiling line or at mid-height of walls.
Vertical cracks
Vertical cracks suggest movement of framing members or foundation. They often occur at wall corners, near door and window openings.
Stair-step cracks
These cracks have an angular stepped pattern. They occur when corner framing members bend or twist due to foundation settlement.
Diagonal cracks
Diagonal cracks appear when a building corner settles unevenly compared to the rest of the foundation. They run at an angle through brick, concrete or drywall.
V-shaped cracks
These cracks have a V-pattern caused by foundation sinking. The wide end of the V is typically nearest to the source of settling.
How to repair wall cracks permanently
Here are some tips to permanently fix wall cracks:
Analyze the cause
Carefully study the crack pattern, location and nature to deduce its probable cause. This will help plan the repair approach accordingly.
Seal foundation and slab
If foundation movement is causing the cracks, seal the foundation and slab with hydraulic cement to prevent water infiltration and further settling.
Repair structural issues
Level sinking foundations, replace damaged framing members and undertake other structural repairs to rectify the root cause before patching up cracks.
Rout out the cracks
Use a concrete grinder or oscillating multi-tool to cut open existing cracks into a neat V-shape. This provides clean edges for the patching compound to bond to.
Apply patching compound
For narrow cracks, use a paintable acrylic latex caulk. For wider cracks, use a paintable patching compound and apply it into the routed-out crack with a putty knife.
Reinforce with mesh tape
Once the compound has partially cured, embed fiberglass mesh drywall tape into it and apply a second coat to fully cover the tape. This reinforces the repair and prevents future cracking.
Blend and finish
Feather out the patched area and blend it into the surrounding surface. Once fully cured, apply primer and paint to match the existing wall finish.
Install control joints
Cutting control joints into the wall surface can help regulate cracking. Install them strategically across areas prone to cracking.
Best permanent crack repair materials
Some ideal materials for permanently patching wall cracks include:
Latex patching compound
Latex-based spackling or patching compound dries fast, sands easily and doesn’t shrink. It bonds tenaciously to surface edges and won’t crack or crumble over time.
Epoxy injections
For deep cracks due to substantial foundation movement, epoxy injection kits can be used to seal them from the inside out in a structural way.
Polyurethane foams
Polyurethane injection foams quickly expand to fill cracks and bond to the edges. They are water-resistant and durable.
Hydraulic cement
Hydraulic cement stops water from infiltrating foundations and is ideal for sealing wide basement wall cracks and slab cracks.
Fiberglass mesh tape
Embedding fiberglass mesh tape into crack repairs adds strength and prevents cracks from spreading. It also bridges cracks up to 1/8-inch.
Tips for preventing future wall cracks
Here are some good practices to reduce wall cracks in future:
Proper foundation design
Engineered foundations appropriate for the site’s soil type will experience minimal settling and prevent cracks.
Control joints in walls
Strategically located vertical and horizontal control joints accommodate normal movement and prevent random cracking.
High quality construction
Good workmanship and use of proper grade construction materials minimizes inherent weaknesses and cracking tendency.
Moisture control
Preventing water infiltration into slabs and foundations prevents settlement cracks. Proper drainage and landscaping helps.
Floating wall finishes
Using two layers of drywall with resilient channels in between accommodates movement without cracking the finish layer.
Avoiding heavy additions
Prevent cracking by not adding excessively heavy materials like tile and stone on top of existing walls not designed to bear the weight.
When to call a professional?
While minor cracks can be repaired by handy homeowners, it is best to call a professional when:
– The cracks reappear soon after repair
– The cracks are very wide, deep and structural
– Walls or ceilings are visibly sagging or slanting
– The cracks keep growing bigger over time
– The cause is suspected to be foundation related
Professionals have right expertise
Licensed contractors have the expertise to correctly diagnose the root cause through structural evaluation and provide appropriate solutions to permanently fix recurring, widening and structural cracks.
They have specialized tools
Professionals have access to specific tools like epoxy injection systems, hydraulic cement pumps, foundation repair techniques etc. for permanent crack repairs.
Full repairs done
They can undertake full foundation repairs like slabjacking, underpinning, leveling etc. if required, along with sealing cracks for a permanent solution.
Warranties provided
Reputable contractors offer warranties on their crack repairs giving you peace of mind. DIY repairs don’t come with such assurances.
The permanent solution
The key to permanently resolving wall cracks involves:
1. Identifying the root cause of cracking by analyzing the pattern and location.
2. Undertaking structural repairs to rectify underlying issues like settling foundations.
3. Properly preparing the crack by routing it out into a clean V-shape.
4. Applying suitable patching material and reinforcing with mesh tape.
5. Installing preventive measures like control joints.
6. Maintaining proper drainage and moisture control.
For recurring or complex cracks, calling a professional structural repair contractor is the best permanent solution. They can diagnose and remedy the specific cause through targeted foundation repairs and advanced sealing methods. With the right approach tailored to the crack type and cause, wall cracks can be permanently fixed and future occurrences prevented.
| Crack Type | Possible Causes | Repair Solutions |
|---|---|---|
| Hairline cracks | Minor foundation movement, Material shrinkage, Thermal expansion/contraction | Seal with caulk |
| Horizontal cracks | Walls settling, Differential foundation movement | Epoxy injection, control joints |
| Vertical cracks | Framing movement, Foundation issues | Rout and patch, foundation repair |
| Diagonal cracks | One corner settling, Leaning wall | Foundation leveling, structural bracing |