As a registered home inspector in New Zealand, I often receive questions about whether a house with plaster cladding is prone to water ingress issues and whether it's a safe investment. Home inspection and building inspection play a crucial role in addressing these concerns. Plaster cladding, often referred to as monolithic cladding, involves the use of whole panels finished with plaster and paint to create an appealing exterior. In New Zealand, this type of cladding typically includes fibrecement, EIFS (Exterior Insulation and Finish Systems), and solid stucco. So why do people worry about plaster cladding leading to water ingress?
The Importance of Exterior Cladding Systems in New Zealand
To understand this, we need to delve into the role of exterior cladding systems in New Zealand homes. Most houses here are built with timber framing, which bears the structural load. To prevent the timber from being compromised by rain, which could lead to rot, an effective exterior cladding system is essential. A thorough building report often highlights the significance of these systems in safeguarding the structural integrity of a home.
When conducting a house inspection to assess potential water ingress risks, consider whether the home adheres to the 4D principles of weatherproofing: Deflection, Drainage, Drying, and Durability.
Deflection: This includes elements like roof coverings and eaves that direct water away from the house.
Drainage and Drying: If water does penetrate the cladding, the cavity system behind the exterior cladding plays a critical role. This system creates a gap between the cladding and the timber frame, with weep holes at the top and bottom to allow air circulation and drainage, thereby preventing moisture buildup and timber rot.
Durability: Ensuring the timber frame is treated for water resistance adds a layer of protection, even if some moisture gets through.
Specific Concerns with Plaster Cladding
Understanding these principles helps highlight what to watch out for with plaster cladding. The concern isn't the plaster cladding itself but the lack of proper 4D support in certain periods and designs. Notably, homes built between 1994 and 2004 in New Zealand fall into a high-risk category for water ingress, often termed "leaky homes." A detailed home inspection can reveal whether a property is at risk of such issues.
Key points to watch for in such homes include:
Built between 1994-2004
Mediterranean-style terraced houses or apartments
Flat roofs or minimal eaves
Internal balconies (balconies that are set within the wall line)
Plaster monolithic cladding with no cavity between the cladding and the timber frame
The Mediterranean-style architecture, designed for dry climates, doesn’t suit New Zealand's wet, marine climate. Flat roofs lack eaves to shed water, and internal balconies can develop cracks at joints. These cracks allow moisture to seep through, clinging to the timber framing. Critically, during the 1994-2004 period, New Zealand regulations did not mandate timber frame treatment for water resistance or the inclusion of cavity systems between the cladding and frame, leading to direct moisture exposure and eventual timber rot.
In 2004, significant amendments to the Building Act required treated timber and the installation of cavity systems. Building inspectors now emphasize these features when evaluating homes with plaster cladding.
Buying a Home with Plaster Cladding
If you are considering purchasing a home with plaster cladding, it's essential to:
Check the build date
Look for design features like flat roofs or lack of eaves
Be prepared for regular maintenance, such as promptly repairing any cracks and ensuring the cladding is properly painted and sealed
Engaging a qualified home inspector for a comprehensive building report can provide valuable insights into the property's condition.
Conclusion
From the perspective of a New Zealand home inspector, understanding the history, design, and maintenance of plaster-clad homes is crucial in making an informed purchase decision. With the right knowledge and proactive maintenance, these homes can still be a viable option. If you have any further questions about home inspections, building reports, or other property concerns, feel free to reach out. As your trusted home inspector, I'm here to help you make the best decision for your future home.
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