Most Common External Plaster Problems in Older NZ Homes

Older homes in New Zealand have undeniable charm, however, they also come with their fair share of ongoing required maintenance issues, especially when it comes to exterior plastering. 

Whether it’s cracking, bubbling, or crumbling plaster, these problems can compromise the beauty and integrity of your property.

At West & Sons Construction, we’ve helped countless homeowners across Auckland and the North Shore and Hibiscus Coast tackle the most common external plaster problems. In this guide, we’ll explore their causes, symptoms, and reliable solutions, from basic plaster repair to full recladding projects.

External Plaster Cracks and Structural Movement

One of the most common plaster problems in older homes is cracking, whether it’s minor hairline fractures or deep diagonal lines.

• Causes: House settling, timber framing shifts, or frequent temperature changes
• Risks: Unaddressed cracks can allow moisture in, leading to crumbling plaster and further damage
• Fix: Targeted remedial plaster repair, possible assessment for structural issues

Learn more from this blog: How Much Does External Plaster Repair Cost in NZ

External Plaster Moisture Damage & Bubbling

Moisture is the enemy of good plaster work. If you spot bubbling or damp spots, you may be dealing with hidden leaks where water damage can cause dangerous mould and rot. 

• Causes: Poor waterproofing, blocked drainage, rising damp
• Risks: Weakening of walls and emergence of crumbling plaster
• Fix: Waterproofing solutions, as well as a full or partial exterior plastering replacement

For more information read our blog: Plaster Repair Explained: Common Issues and How to Fix Them

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Plaster Efflorescence

This white, powdery buildup on plaster walls is caused by salts surfacing through moisture movement.

• Causes: Damp environments and poor ventilation
• Risks: Visual damage and early signs of deeper deterioration
• Fix: Surface cleaning, moisture detection, and sealing, especially critical for exterior plastering

Exterior Plaster Peeling, Flaking & Hollow Sounds

Plaster that’s loose or hollow when tapped is a clear sign that it’s pulling away from the structure.

• Causes: Moisture, age, or poor bonding methods
• Risks: Large areas of crumbling plaster requiring more than a quick fix
• Fix: Remove all compromised areas, assess for full plaster repair or recladding

Poor Plaster Application & Shrinkage Cracks

Quick drying or incorrect plaster mix ratios can lead to surface cracking over time. This is why it pays to ensure your plastering team are local, seasoned professionals and Licensed Building Practitioners. 

• Causes: Rushed installation, unsuitable materials for NZ conditions
• Risks: Cosmetic issues now, potential moisture entry later
• Fix: Professional plaster repair using modern, breathable products tailored for long-term durability

To understand why qualified plasterer and construction staff are so important, read our blog: Why Hiring a Licensed Building Practitioner is Essential

Exterior Plaster Discolouration and Staining

Surface stains may seem harmless but can point to lingering moisture or aging materials.

• Causes: UV rays, mildew, incompatible paint
• Risks: Hides deeper common plaster problems and weakens finishes
• Fix: Clean, repaint, and check for early signs of crumbling plaster

West & Sons Construction Can Help fix Your Damaged Plaster

We’re trusted across Auckland and the North Shore for expert plaster repair and rejuvenation of heritage homes. Here’s what we offer:

• Moisture detection & assessment
• Repair of all common plaster problems
• Expert exterior plastering and recladding
• Restoration of crumbling plaster and weakened structures
• Heritage-friendly materials and workmanship

Don't let minor plaster problems turn into major repairs, with West & Sons Construction, you'll get honest advice, professional service and results built to last.