Cracks in Walls |Types of Crack in Concrete | Hairline Cracks | What Causes Cracks in Walls
Cracks on concrete walls are not uncommon especially for newly built houses. Cracks on walls may just be a small problem like hairline cracks, but it could indicator of a more serious structural problem. The first step to fixing the problem is identifying. Once identified, the solution to fix follows.
Types of Cracks in Concrete Walls and Floor
Sometimes cracks occur in your concrete slab or concrete floor unrelated to your foundation or the general structure of your home. Often, these cracks are noticed when the floor above the concrete slab becomes damaged by the uneven concrete. Usually, the damage to both floors is caused by the presence of water.
7 Types of Crack in Concrete Walls and Floors
Here are common types of crack in concrete:
Shrinkage Concrete Cracks
These cracks have a V-shape (less frequent), with the top of the crack looking larger and the crack getting smaller as it travels towards to floor and diminishing or stopping before reaching the bottom of the foundation wall. If the crack reaches the bottom, the crack might damage the building’s footings, and the crack might have a significant impact on the foundation structure.
Settlement Concrete Cracks
Settlement cracks may appear when the underlying ground has not been compacted or appropriately prepared or in areas where the soil of the subgrade was uneven after the concrete was poured. This type of crack is usually continuous and may occur multiple times in a wall.
Horizontal Concrete Cracks
Horizontal cracks are found in the center of the wall are most likely caused by an applied load such as heavy equipment operated too soon or too close to the foundation wall. Horizontal cracks found high up on the wall are most likely caused by frost damage. Sometimes these fine cracks are not noticed for years. In a case like this, a structural engineer should be consulted.
Vertical Concrete Cracks
Vertical cracks tend to appear nearly straight or wandering, generally even in width, intermittent, or more often straight is caused by shrinkage/thermal and are usually low risk. If there is significant vertical dislocation or signs of ongoing movement, you should consult a structural engineer.
Diagonal Concrete Cracks
Settlement cracks can also cause a diagonal crack. In a case like this, a structural engineer should be consulted. If the diagonal crack is wider at the top than at the bottom, then it may be caused by expansion clay soil or frost damage. If the crack is wider at the bottom than the top, there is likely a problem with the settlement beneath.
Floor Crack in Concrete
Floor cracks in concrete slabs are relatively common and usually not worrisome on a structural level. They should be repaired to prevent common issues like moisture, insects, and damage from seeping through.
Hairline Cracks on Concrete Walls/Floors
Hairline cracks appear in the center of the walls because the wall corners have greater stability. This happens shortly after pouring the concrete foundation, concrete may have been mixed poorly or poured too quickly. Hairline cracks do not cause problems with the stability of the foundation but do cause leakage problems.
Hairline cracks in plaster walls are not uncommon and are purely cosmetic and caused by the slight contraction and expansion of the mortar of the house during seasonal changes. Other cracks in internal walls may be indicators of more serious underlying issues such as subsidence, poor initial design, or structural and foundation defects.
Cracks in the wall at building inspection may necessitate expert intervention that can be costly.
Causes of Hairline Cracks on Walls; Why do Hairline Cracks on Walls occur?
Here are a few common reasons:
- Contraction and expansion of the materials which can be either paint or plaster because of fluctuations in humidity levels and temperature changes. The movement of contraction and expansion can cause hairline cracks to appear.
- Low-quality paint or inferior quality paint results in poor paint adhesion on your wall, which leads to cracks over time. In addition, using different paints for each paint coat can also cause cracks on the wall.
- Impatience during plasterwork. Not letting cement plaster completely dry before applying paint is actually quite a common factor attributed to cracks.
- Poor paint job: Painting an entire house can be a huge amount of work, and it can be tempting to rush through it. But mistakes like missing out on layers, or not letting previous layers completely dry can hamper your overall efforts.
Causes of Cracks on the Concrete Walls
Below we highlight the reasons which may be the cause of cracks on your wall
- Shrinkage in Blocks or poor quality of blocks may also cause a crack in a wall.
- Use of rich cement mortar i.e. the cement content is higher than specified in the design mix.
- Use of very fine sand to make mortar i.e. higher silt content or use of sand which is not graded properly.
- The higher water-cement ratio in the mortar mix.
- Improper curing.
- Poor workmanship.
- Higher thickness of plaster.
- Early application of putty i.e. putty is applied just after curing.
- A temperature at the time of application of plaster. i.e. shrinkage cracks are more prone in the summer season than in the winter.
- Humidity at your location. i.e. relative humidity in the coastal region is high through the year hence this area is less prone to cracks.
- Continuous vibration or frequent hit by a hammer for nailing may also be a reason
Foundation Repair for Slab Cracks
If you spot any cracks in your house foundation, a repair expert should check it as soon as possible. Some cracks are simply superficial, however, others can pose a huge risk.
Cracks in your house’s foundation can occur obviously from settling, and in many cases, tiny cracks do not indicate a larger problem. In other instances, however, cracks do indeed pose a major risk. So how can you tell the difference?
What is a Slab Foundation?
Homebuilders use numerous types of foundation structures, relying on soil conditions and architecture styles. The most common foundation these days is the monolithic concrete slab.
A slab foundation is made of a single layer of concrete poured with some inches thickness, and thicker at the rims so as to form footings. It is similarly bolstered through reinforcing rods of metal rebar. Slabs are generally poured on top of a bed of crushed gravel to provide good drainage. In many instances, plumbing and electric connections are placed in the slab itself.
This sort of foundation works fine in regions wherein the floor does not freeze, however, it could be adapted to fit different areas.
Interior Signs of a Crack Slab Problem
Foundation settling is bound to take place over time. This among others causes foundation cracks. Some signs of cracked slab include;
- A door does not open smoothly as usual or gets stuck
- Cracks in partitions, especially over doors, windows or wherein the partitions and ceiling meet
- Cracks in the vinyl or ceramic tiles that cowl a concrete floor
- Windows that when opened easily but now stick or won’t near all the way
Exterior Warning Signs of a Foundation Problem
When you see stucco cracks or z-formed cracks in brick or concrete, this could be an indication of a foundation problem. Again, a leaning chimney is a positive sign of an issue so is the presence of moisture, mould, or moss along cracks seen on the outside slab or the bottom of walls.
In and around your garage, take note of the walls are beginning to separate from the garage door, or if the garage door might not open easily.
Concrete Slab Foundations Problem
Concrete slab foundations are generally dependable because they withstand movement and settling. But whilst the soil below expands and contracts, the pressure is exerted on the concrete. Typically this happens because the soil gets moist after which dries out, however it may additionally occur if the underlying soil was not compacted well when being made.
The location of cracks does not always indicate where the problem is. Cracks act as hinges that offer movement for the slab as it shifts, similar to earthquake pressure.
However, the soil might be subsiding anywhere beneath the slab, not necessarily immediately under the crack.
Solution to Cracked Slap Foundations
The general rule is that any crack of a quarter-inch or much less is probably is not an issue, but anything wider than that needs a serious look. Many homeowners often play it safe by not engaging the structural to assess the foundation condition in the early stages of crack development. This may ultimately prove to be expensive in the long run.
In most cases, maintenance will help save you any additional structural damage.
Repairs to a cracked slab may be achieved in many ways depending on the magnitude and source of the crack. In most cases, the contractor will install helical piles to help the load of the shape, easing the load stress at the slab itself and stopping further damage.