Concrete blockwork – leaking through cladding

Cause

Cracks in the concrete block

Repair

  • before repairs are undertaken you will need to establish the cause(s) of the cracking and whether the cracks are stable or are widening. This will help determine the course of action
  • you could consult an experienced building surveyor who is a member of an industry body such as the New Zealand Institute of Building Surveyors (NZIBS) for advice on the scale of the problem and potential repairs. For severe and extensive cracking, and cracks that are widening, you may need to consult a chartered professional engineer
  • building work to address weathertightness issues in homes is not DIY work. You should only consider doing this work yourself if you have the knowledge, skills, experience and tools to do the job. Most homeowners should call in a well experienced builder
  • if the cracks are not widening and have been filled, allow the blocks to dry thoroughly. This will take time. Once dry, scrape and/or sand off loose paint off the blocks to leave a clean, sound surface. Prime and paint with a minimum two coats of good quality paint suitable for concrete masonry

Cause

Paint or sealant failure

Repair

  • follow the recommendations in the first repair above

Cause

Junctions with other claddings and/or roof poorly detailed/constructed

Repair

  • follow the recommendations in the first repair above
  • if the wall was constructed within the last 10 years, contact the designer and the builder. You can take action for up to 10 years after building work is completed if implied warranties set out in the Building Act have not been met. These include requirements that work be done with reasonable care and skill

Cause

Moisture absorption through the masonry when left unpainted

Repair

  • remove the foliage and identify the extent of damage and work required
  • follow the recommendations in the first repair above