Why do you need ventilation? The crucial role of passive ventilation in your next project - Roof Ventilation

Homes are more weathertight than ever. This is great news for our overall health and energy efficiency. But homes without airflow create an alarming moisture problem tightly regulated in other parts of the world but not in New Zealand. Let’s take you through why you need ventilation now for a better, future-proofed build and how you can be prepared before ventilation becomes standard in NZ.

As the building industry has realised old homes were affecting our health and efficiency, insulation and airtightness requirements within New Zealand’s building code have increased. Making it more affordable to heat homes, a win for healthy homes across NZ with a notorious record for draughty, cold, damp-ridden homes.

Why are airtight homes a bad thing?

Simply put, they’re not! But many new homes focus on increased insulation and leave out an essential building block to breathable, dry homes. Draughty, damp homes lead to a raft of respiratory issues for your family and are eye-wateringly expensive to heat. Insulated homes are great homes in our eyes. But, they need ventilation.

Why Ventilation Matters

Ventilation plays a vital role in maintaining a healthy indoor environment. We don’t want draughty homes, but ventilation lets fresh air into super airtight homes, especially when the air temperature drops dramatically from day to night. It’s also crucial to allow the structure of our homes to breathe.

Airtight home with ventilation

Airtight home without ventilation

In a well-ventilated home, air circulates freely, carrying away moisture and pollutants preventing condensation buildup that leads to mould. In tightly sealed, well insulated homes natural ventilation is often compromised, leading to stagnant air and potential moisture issues. We’ve seen homes as little as one year old with mould issues in the roof cavity due to lack of ventilation.

How does mould infiltrate a brand new build?

Mould thrives in damp, poorly ventilated environments. With tightly insulated homes, hot air gets trapped in cavities and turns into condensation as the weather cools at night. Condensation can dry up without a problem if there is airflow, but without airflow it settles into the wooden structures of our buildings. New Zealand’s climate is ripe for condensation, we have relatively warm days, and then the air temp drops dramatically at night, especially in the South Island, creating the perfect storm for moisture build up.

The transition from moisture to mould growth doesn’t happen overnight but in a relatively short time for a new build, this can happen in one to three years down the track where mould is covering trusses and risking the structural integrity of a new home, not to mention a homeowner’s significant financial investment.

New Zealand’s Hidden Mould Problem.

Roof ventilation regulations are already in place in Australia, Europe and the UK to mitigate the effects of condensation build up in completely airtight homes.

The challenge for New Zealand lies in striking a balance between energy efficiency and structural breathability suited to our specific climate. While essentials like insulation and double glazing are instrumental in reducing energy consumption, they must be complemented by measures to ensure our new builds don’t suffer from internal mould issues.

By prioritising energy efficiency and air flow, we can create homes that are sustainable, warm and last well into the future. Integrating cost effective ventilation systems alongside extra insulation and double glazing is crucial in achieving this balance.

Vent offers a wide range of ventilation products which can be tailored to your build to create a complete ventilation system, allowing you (and your project) to breathe easy, knowing your builds are protected from internal moisture issues.

Protecting your Liability.

Mould build up in homes is not just a maybe, there is evidence of mould growing within cavities of New Zealand homes that are only one to three years old, caused by lack of ventilation in airtight homes. While it’s not regulated in New Zealand as part of the building code, it does recommend managing moisture in cavities through ventilation.

Lessons from Australia.

Australia is currently rolling out roof ventilation requirements state by state. They are following Europe and America to incorporate cavity ventilation into weathertight builds to allow their homes to breathe.

Australia’s NCC 2022 introduced significant changes regarding roof ventilation, aiming to improve energy efficiency and building performance while also allowing for air flow, including:

Performance-based requirements: Considering factors such as roof pitch, insulation, and climatic conditions and ensuring ventilation systems are tailored to specific building requirements.
Increased ventilation rates: The new code requires higher minimum ventilation rates, ensuring a greater exchange of air between the attic space and the external environment. This promotes better air quality and reduces the risk of moisture-related issues.
Enhanced insulation compatibility: The NCC 2022 emphasises the compatibility between insulation and roof ventilation systems. Adequate insulation should not impede or block ventilation pathways, ensuring an unobstructed airflow.
Fire safety considerations: The updated code places importance on fire safety by requiring roof vents to be constructed with non-combustible materials and designed to minimise the spread of fire.

Contact us for a yarn about integrating our cost effective, complete ventilation systems into your next project.