How to monitor cracks

Worried About Cracks In Your House? Having Sleepless Nights?

crack
Here the foundation on the corner of the domestic bathroom had subsidised! Disguising cracks with paint and Polyfilla won’t work! You need to find the cause fist and fix that before you patch walls!
crack
The problem here was with the pooling of water on the paving and the level of the paving being close to or at the floor level of the bathroom. In addition, it appeared the bath waste or water supply may be leaking.

How to monitor cracks in your walls and floors!

Generally, concrete, stone, brick and masonry walls and concrete or screeded floors that have cracks less than 1 mm wide (the thickness of a credit card) are common and usually do not warrant any corrective action. Most of these small tight cracks are caused by normal settlement of the structure which usually occurs within the first few years after construction.

However, changes in condition around the structure may also cause settlement many years later. Examples are planting a new garden or tree or removing a garden or tree that is against or close to the house.

Crack Fillers

Note that all cracks should be sealed with paint, caulk (sealer) or mortar to prevent water from getting into the structure.

Moreover, if a horizontal, vertical, or diagonal masonry crack is filled with hard masonry patching compound, any substantial future movement is likely to show up as a new crack in the patched area or nearby.  Therefore, always use a non-shrinking grout to prevent stressing yourself!

Continued movement

Cracks that continue to move are a reason for concern! Continued movement in cracks should be evaluated as there may a need for corrective action. Therefore, if you notice a crack has re-cracked or the crack has opened or gotten larger it should be monitored! However, first, make sure there is no shrinkage of the filler product.  All cracks that are 5 mm and greater should be carefully monitored to ensure there is no continued movement.

Measuring and Documenting Movement

A single masonry crack alone may not be the only nor even the most critical evidence of foundation movement. Moreover, if a foundation or superstructure wall is leaning, bending, or bowing, the movement may cause stress resulting in a series of smaller cracks that will not adequately reflect the total amount of foundation movement. Therefore, also monitor a series of smaller cracks!

Examination of Cracks

Examine the nature and severity of the crack:
  • What direction are the cracks going and are they wider at the top or bottom? Make a note of this!
  • Take note of sloped floors, bulging walls and doors that do
    not fit.
Look for the probable cause:
  • Foundation erosion.
  • Decay and/or improper use of building materials.
  • Structural failure.
  • Change in materials or shape.
  • Changes in moisture content.
Thermal changes:
  • Horizontal or diagonal cracks near the ground in long walls due to horizontal shearing stresses between the upper wall and the wall where it enters the ground,
  • Vertical cracks near the ends of walls,
  • Vertical cracks near the top and corners of the exterior walls,
  • Cracks around sills or lintels due to expansion of the masonry against both ends of the tight-fitting concrete or brick piece that cannot be compressed.

Monitoring fractures – Three Simple Methods

Using Tape and Pencil:
  • Firstly, place a high-quality sticky piece of tape on each side of the crack.
  • Secondly, draw one short line on each piece of tape at a convenient distance apart (50 mm) and parallel to the crack. Use a ruler to measure as exact as possible or use something as a template for multiple marking.
  • Therefore, if there is movement in the crack, the distance between the line on the tape will vary. However, if the crack is long, several monitors will be needed.
  • To monitor the length of the crack mark the ends of the crack as described in (2) using the tape
Marking the wall
  • If you are not concerned with marks on the wall, use a sharp-pointed marker or pen and a ruler make a mark on either side of the width of the crack. In addition, the marks should be 50 mm apart!
  • Therefore, if there is movement in the crack, the distance between two marks will vary. However, if the crack is long, several markings will be needed.
  • To monitor the length of the crack, mark the ends of the crack. If the crack lengths mark it again after a week and measure the length of the movement.
Using Glass and Epoxy:
  • Take a small piece of single strength window glass a microscope slide is good) to bridge over the crack.  Then, epoxy the ends of the glass to the masonry on either side of the crack; locate it in an inconspicuous place.
  • If the glass breaks, it is an indication that the walls are still moving and that the crack is widening.

Record Keeping

Make a record chart of the distance between the marks of the tape at weekly intervals. Furthermore, keep accurate records of these measurements and place them along with photographs in a file. If significant widening occurs, report this with back-up data and copies of photographs to a structural engineer or suitably qualified home inspector for a consultation.

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