Retaining wall bowing, bulging, tilting

  • tilting of a concrete retaining wall

Crusade

Inadequate blueprint/foundations/construction

Repair

  • the wall is probable to need replacing. Check whether piece of work requires a building consent. Edifice or repair piece of work on a wall retaining less than i.5 metres of ground and not supporting a surcharge does not require a building consent. (A surcharge is an additional load on the land in a higher place the wall, such as a car park or driveway.)

  • if the wall is taller than 1.5 thou or there is a surcharge, then building consent is required. When a edifice consent is required, the wall must be designed by a registered engineer

  • some proprietary retaining wall systems (particularly crib walls) have pre-engineered pattern tables that may be used without the need to engage an engineer

  • BRANZ recommends that communication is sought from a chartered professional (structural) engineer for all walls over 1 m high. In some circumstances (such as shut to buildings) lower walls may as well benefit from applied science advice

  • where there is a suspicion of footing movement, getting advice from a geotechnical engineer is recommended

  • even where consent is not required the wall must still comply with the Building Code, including clauses B1 Structure, B2 Durability and F4 Prophylactic from falling

  • in almost all circumstances, skilful piped drainage behind the wall is essential to dispose of water – a build-up of water behind the wall is the principal cause of retaining wall failure

  • for more than guidance see the Build mag articles online here and hither

Cause

Overloading from soil/vehicles at tiptop of wall

Repair

  • come across the comments for the repair above. Where the retaining wall is supporting a surcharge – an additional load on the land above the wall – rebuilding the wall volition crave building consent, and the pattern must be by a registered engineer

Crusade

Pressure from soil/build up of water backside retaining wall due to blocked or no drainage

Repair

  • ensure drainage slots and/or soil drains are clear
  • bank check that at that place are no leaking drains above or behind the wall
  • if necessary, consult a chartered professional (structural) engineer to formulate repair or replacement options. For lateral ground movement contact a chartered professional person (geotechnical) engineer to advise on how to remedy

Cause

Lack of costless-draining material behind wall

Repair

  • come across the comments for the first repair above. Where damage to the wall is only slight and the wall is non too high, digging out the ground behind the wall and installing appropriate drainage, backfilling with free draining material, may be possible. Where the wall is more seriously damaged, replacement may be necessary.

Crusade

Incorrect wall slope

Repair

  • replace retaining wall – consult a chartered professional (structural) engineer to formulate repair or replacement options. For lateral footing motion contact a chartered professional (geotechnical) engineer to advise on how to remedy

Repair

  • meet the comments for the start repair above. The tree roots will certainly need to be removed, and to avoid future harm the tree itself should be removed

Cause

Basis in front end of retaining wall has been excavated/undermined

Repair

  • •see the comments for the first repair above. Professional technology communication is recommended