Our story is a response to NZ’s biggest problem; the deterioration of timber frame construction over time... 

  • POROTHERM Clay Block Construction is a thousand year old European building method now available in New Zealand as a state-of-the-art precision engineered building technology. And it can now be affordable! 
  • Up until now, the only choices in building were concrete masonry, lightweight concrete and timber – along with a few others such as rammed earth.
  • Cost is always a major factor when designing & building. For many reasons, POROTHERM provides a unique construction alternative to the health problems & economic costs that many New Zealanders are currently facing.
  • By taking the ‘Fabric First’ approach, POROTHERM Clay Block Construction is about THERMAL MASS – heating & cooling a building at near zero energy levels.

It’s about living in a breathable ECO building – no ‘out-gassing’ for 6 months while the formaldehydes, tanalising or insulation chemicals find their way out. Lime plasters & mineral paints provide a perfect complement to the natural block making the indoor air quality 100% natural & healthy. No toxins & moulds, ever!

It’s about seismic strength & durability. A POROTHERM home has a design life of over 150 years & a material life well beyond that – your life investment is safe. It is design-engineered to meet the requirements of high seismic zones worldwide.

It’s about economics – A POROTHERM plaster-finished wall will compare on a m2 rate to a 140mm timber frame wall finished with brick veneer cladding – very competitive.

A POROTHERM home can achieve near zero energy and maintenance costs adding to savings. Construction speed is 4 times faster than traditional masonry construction. POROTHERM Clay Block Construction is perfect for inter-tenancy walls, multi-level & commercial construction. Maintenance is minimal.

It’s about caring for our environment – it uses 95% less water, has 45% less waste on site and is comprised of up to 30% MARSS – materials from alternative, recycled & secondary sources. The clay block is low embodied energy; even to get it to NZ from Europe. The manufacturing ethics of Wienerberger means the cost to the environment still out-performs traditional construction materials produced locally. Sustainability is at the heart of all Wienerberger’s operations.

Building with POROTHERM is simple & fast. No complicated cavity or design systems, no co-ordination of contractors to site – just blocks & plaster (or cladding of your choice), the ‘fabric’ of the building. Licensed blocklayers are qualified to work with this system, and Stellaria has chosen to work with specific regional partners across NZ to ensure all blocklayers are LBP accredited with a proven track record to correctly install POROTHERM. Stellaria recommends only a few specific plaster companies with a worldwide reputation & proven, long term record for the plaster finish.

Living with POROTHERM is an e4 journey – emotion, environment, energy & economics. The emotion of knowing your home or your investment is 100% natural & pure. You know your family’s health is not at risk from toxic moulds and respiratory conditions – sadly, all too common in NZ.

The environment is not impacted by the manufacture of clay blocks and any waste material can be safely returned to the land – no timber or polystyrene in the landfill, just regenerative clay – cradle to cradle. Energy consumption is minimal. The sheer thermal mass and thermometric regulation of the block means your home is perfect for Passive Solar Design – it can retain a temperate 20 degrees year round when designed correctly.

With increasing capital value due to its masonry composition your investment is safe, durable and will outlast many generations. You and your family are 100% protected. It all makes common, down-to-earth good sense.

We are Chris & Robyn MacPherson of MacPherson Architecture Ltd, Cambridge NZ. We have been designing residential homes & commercial buildings for over 20 years and we’re passionate about passive solar architecture, sustainability & durability in the built environment. Frustrated by the limited choice of building materials and appalled by the condition of some of NZ’s housing, we wanted to find an alternative solution. So we partnered with the largest worldwide clay producing company, Wienerberger, to offer real building solutions & choice of material to NZ architecture & construction. All installers of the POROTHERM Clay Construction Block system are required to be licensed & certified by Stellaria NZ Ltd. 

Meet the Team


                         Katie Hine                                               Marketing Assistant                                     katie@stellaria.co.nz               07 823 1516


                    Federico Carranza                                   Architectural Technician                             federico@macarch.co.nz                  07 823 1516

                    Christina Balsom                                            Administrator                                       christina@stellaria.co.nz                07 823 1516