Why Porotherm

Dear Homeowners,

The majority of houses and buildings in New Zealand are constructed using under-performing timbers and cladding systems not suitable for NZ’s climate and high humidity.
This has resulted in what is now well-known as the ‘Leaky Homes’ disaster – one of New Zealand’s most significant financial and emotional crises.
For many years, native timbers worked well and many of NZ’s first homes and villas are still standing strong after one hundred years plus – but this is no longer the case in our country.
The life expectancy of our modern timber homes should be at least fifty years but with a Master Builder’s guarantee of only ten years, what happens to your investment for the next forty plus when something goes wrong? Good framing and good cladding, built well is essential for longevity – but what if you don’t have that?
Tanalised timber frame housing using Pinus Radiata with cheap, man-made cladding creates a whole range of issues – sometimes soon after your house is finished.
• If your home is not built to a high standard of workmanship using quality, durable and proven materials, moisture can quickly get in to cause deterioration behind and within the walls – often unnoticed by it’s owner.
• The complexity of timber construction to remedy this only complicates matters further if any part of the wall should fail at any time.
• Creating air-tight timber frame homes, mostly locked up during the day and night with high moisture content and diminished ventilation due to our modern lifestyles is unsustainable. Adding more heat recovery and de-humidifying systems is not the answer.
• Contracting and expanding in cold, damp winters to hot, dry summers is causing many of our homes to ‘pop’ and crackle, literally.
• Adding more air conditioning and extra heat pumps is expensive and for many NZers, prohibitive.
• Out-gassing by the preservatives used in the tanalising and building process occurs within the first six months of living in your new home. Sickness, asthma & related respiratory problems are on the rise and rise in NZ.*
• Given the cost per/m2 to build in timber frame versus performance in energy and maintenance requirement is a false economy.
• The cost to run and maintain your home de-values your investment every year
• Your investment is further diminished by the lack of any promise for durability. If you don’t keep selling and moving or spending large amounts on repairs and maintenance every ten years at least, your children and grandchildren stand little chance of inheritance.


This is the state of a large number of houses in New Zealand; houses that are quite likely homes for your loved ones, either now or in the future.
While many genuine attempts are now being made in NZ using available materials by building smarter and better, most new timber homes struggle to perform at any level of significance, continuing to cost owners and occupiers. Short term and low-cost thinking has become our country’s greatest expense.
For the same m2 rate as a high-end timber frame home, Porotherm clay block walls perform at every level by replacing the energy and maintenance costs significantly with long term financial and emotional benefits for you and your family. Being masonry by definition, it is much less costly to build than concrete block or tilt slab and on par with 140mm timber frame quality fit-out/ finish. Considering the cost to build versus the cost to run and maintain your home – Porotherm is by far the best option, and here’s why:
Clay block construction constitutes up to 80% of the building material of choice in Europe and growing worldwide – despite superior local timbers.
It takes twelve hours for the heat and cool to move across the block – therefore with occupancy and sunshine on your walls – if you are not there, it can be up to 3-4 days before your home begins to cool down in winter and the opposite applies in summer.
Your walls will breathe, remaining fresh and clean. No out-gassing or ill health. No moisture to worry about.
Your home will have a design life of 150 years+ but a material life of 400+ years – no kidding!
Believe it or not – it’s affordable at every level. In fact, with the rising cost to build, you can’t afford not to think seriously about how your home will or won’t perform or how long it will last.
Spend a bit more on quality and save on energy and maintenance costs. We take the long view and would love you to join the revolution with us…
POROTHERM is the perfect building material

*See NEWS for articles related to Leaky Homes.

Wienerberger Porotherm Clay Construction Block Wall - Stellaria NZ