Building Repairs – Identifying Cracks In Brick Walls
First let us identify the wall crack and then we can determine how to fix the crack.
Identifying the Surface Crack
Surface cracks occur in the finishing plaster. The cracks are mostly caused from the plaster not having gone through the correct plaster curing procedures. This results mostly in hairline cracks up to 1mm cracks.
How To Repair The surface Crack
Open the crack with corner side of a paint knife running it along the cracks opening it slightly. Plrime the cracks with a multi surface prime and allow to cure. Apply masonry filler with a bonding agent mixed into it. When dry sand and apply primer and paint.
Settlement cracks occur as a building begins to settle. These cracks commonly appear above doors and windows. Generally settlement cracks are relatively easy to repair. Settlement cracks can be more severe when builders have not compacted the ground correctly prior building. or when design has not anticipated the settlement of building weight to ground density correctly.
Settlement Crack Repair
Open the crack and remove loose mortar and brickwork as necessary. Insert a stainless steel or galvanized mesh between the brickwork and the mortar making sure the mesh ties the wall together and allow mortar to cure for 2-3 days. Do not apply finishing plaster until the repair has cured.
Identification of Subsidence Cracks
Subsidence are generally the more severe and wide crack. These cracks happen when the earth below the foundation diminishes due to the following factors.
- Movement of water below the foundation washing away the soil.
- Undetected debris beneath the soil gives way as the building settles.
- Soil cavities.
There are many reasons for subsidence cracks and the cause is the ground below the foundations have become subject to deterioration.
How To Repair Subsidence Cracks
Once the cause has been identified and the problem dealt with in case of water being re-routed etc. Repairs generally require the underpinnig of foundations. Subsidence cracks would be best inspected by a structural engineer.
Identifying wall tie cracks
Wall tie cracks are when walls have not been tied in together. They re often seen as straight line cracks
How To Repair Wall Tie Cracks
Open up the wall at every fifth course brickwork and insert a brick or steel strap or flat bar between the two walls to bind them together. Close and finish with a steel trowel and mortar.