Brick Slips Provide a Lightweight and Fast Alternative to Full Brick Facades

Brick slips are an exciting and innovative way to create a beautiful brick facade without the weight and installation cost of full bricks.

Brick Slips are thin sections of brick that replicate the look of conventional brick work and can be used both internally and externally. Available in New Zealand through Stellaria, Brick Slips can be supplied in the complete Wienerberger product range, giving designers a unique variety of styles and colours to suit both contemporary and traditional designs.

Brick slips are produced in one of two ways:

Firstly, they can be cut from the face of a standard brick. This is a more traditional method of Brick Slip production and allows flexibility with the thickness of the slips.
Secondly, in a similar way to the process used for standard wirecut brick production, a column of extruded clay is wirecut into the required slip thickness before being kiln fired. This is a more cost-effective production method; however this method does not offer the same levels of flexibility in size as the cut from a standard brick does.
Brick Slip return corners are also available in thicknesses to match all the available standard slip sizes. These units allow the seamless continuation of the required bond pattern to offer the complete look of conventional brick work.

Quick and cost effective:
Brick Slips are a quick and cost effective way to replicate the look of conventional brick work, providing excellent durability and low maintenance, the brick slips are ideal for new build or renovation projects and are incredibly easy to fit and point. Suitable for a wide range of external wall insulation systems, the brick slips also offer an easy way to transform or improve the look of any wall, whether internal or external.

Increasing in Popularity:
Brick slips have become an increasingly popular choice, particularly for use with external insulation systems where people still want an authentic brick look alongside the increased insulation performance and reduction in wall thickness and weight.

Available in a Broad Range of Designs: 
Stellaria NZ supplies Brick Slips from Wienerberger, one of the world's largest brick manufacturers. Designers can choose from any of the hundreds of Wienerberger bricks available as brick slips. This means they can match existing brickwork in an easy and hassle-free way. Brick slips can be offered in a variety of thicknesses to suit different designs.

Wienerberger also offers an extensive range of purpose-made brick slips. These specially produced brick slips are made on their own extrusion line. This makes them more cost-effective than cutting slips from full bricks, and reduces wastage.

The Wienerberger range of purpose-made brick slips come in 215 x 15 x 65mm dimensions, meaning they are light weight. An additional benefit of this range is that they are all produced on the same red body. Extremely durable colours are bonded into the surface during firing at over 1000°C. This means that whatever colours are chosen, they all have the same technical specification and size consistency.

Carrowbreck Meadow – UK Passivhaus Development with Social and Environmental Sustainability

Porotherm has been used extensively throughout Europe since its conception in 1976, but clay has been a durable and reliable building material for generations more. It goes without saying that Porotherm was a great fit for a Passivhaus development in the UK. The Carrowbreck Meadow development leads the way in both social and environmental sustainability. “Some are rented; some are sold on a shared equity basis. The fourteen units were built to Passivhaus standard because "it means reduced need for space heating and higher levels of comfort and wellbeing.” Good for both residents and the environment.

"The project was built on a tight budget and schedule, so the architects have used some interesting innovations including Porotherm clay blocks with a "unique interlocking design rules out the need for mortar in the vertical joints and consistent manufacturing quality allows for true 1mm bed joints. Used successfully for decades across Europe." According to the architects brief, it is faster and comes with a design life of 150 years.”

Check out the full article from Treehugger here 


E4 BLOCKHOUSE  – A Case Study on Seismicity for POROTHERM in Martinborough

Eboss Detailed Blog published HERE

The ground floor is up, stresscrete mid-span floor going on next week – this is the long-awaited Martinborough e4 BLOCKHOUSE going up at last. 

As seismicity is first & foremost on everyone’s minds, especially in NZ’s 2nd highest seismic zone, Martinborough - we wanted to be ahead of our game so our Engineer Ted Dowdall, SENZ suggested we should consult with one of the world’s highest authorities for seismic design of both reinforced and pre-stressed masonry buildings, Professor Jason Ingham. Dr Ingham is Head of Department at Auckland University of Civil & Environmental Engineering. One of his many research groups is the University of Auckland Centre for Earthquake Engineering Research(UACEER).

Dr Ingham worked with Ted prior to lodging building consent, to produce a Peer Review we were confident would stand up to very tough scrutiny. It was a very positive journey with a great outcome for us all. 

In Ted’s own words…
Currently, New Zealand codes (which don't have confined masonry design within them) limits ULS (Ultimate Limit States) deflections to 2.5% × the storey height, or "such lesser limit as may be prescribed in the appropriate material Standard". So were there to be a code for confined masonry, this figure could easily be less. Basically it allows "flexible" buildings to drift 2.5% either way in a severe earthquake. So for a 2-storey building say 6.0 m high the limit would be approximately 150 mm.
Eurocode 8 limits ULS inter-storey to 0.8% i.e. 48 mm for a 6.0 m high building, a considerable difference. I suspect were there to be a New Zealand code, it would restrict allowable deflections to something more like this, the limits in the New Zealand code are clearly written for timber or steel buildings, or reinforced concrete buildings with moment-resisting frames, all of which are designed to be flexible. Reinforced concrete buildings with shear walls are much more stiff.
For the Martinborough e4, under ULS loadings, the building structure only deflected a certain amount in any particular direction under any particular earthquake (there were 16 different types of analyses) before the walls failed due to bending or shear rather than displacement. These deflections varied between 1.3 mm and 2.6 mm but they are not in any way a reflection of the building's capacity, because the buildings failed due to other reasons than reaching the deflection limits.
Essentially were we to strengthen the building, then it would be able to take higher forces, and under those forces it would deflect more, so you can't read too much into the actual figures. I hope that makes sense.
For instance the Taupo project analysis currently reports between 7.4 mm and 16.5 mm deflection depending upon which earthquake direction and loading pattern is considered. This is mainly due to the large amount of glazing all along the front wall of the building. It is much more flexible than the e4, but it is still nowhere near the deflection limits which would be something like 48 mm.
So you can't generalise for POROTHERM construction, each individual building will have its own characteristics. All you can say is something like this:
"Under current New Zealand codes & standards, deflection limits for buildings under ULS loadings are approximately 3 × those required by the Eurocode method of design, and generally houses constructed from POROTHERM do not come anywhere near these limits when analysed. So houses constructed from POROTHERM are extremely stiff and much less liable to cracking under earthquake loadings, than traditional timber-framed structures, or indeed most other types of construction currently used in New Zealand”.

2020 Near Zero Energy Standards for Climate Neutral Buildings

A nearly zero energy house is a building that covers most of its low energy requirements with renewable energy sources.

Wienerberger implements future-oriented nearly zero energy standards in Austria. The innovative model house with an energy-efficient clay block envelope is made of high thermal insulating Porotherm clay blocks with integrated insulation as the heart of the house. The focus is on affordability and minimisation of costs and to meet all requirements of the 2020 EU building directive.

The issue of sustainable and energy-efficient construction has been an important focal point of activities at Wienerberger AG for many years. Wienerberger took another important step with the July 2011 start of construction on e4 BRICKHOUSE 2020 in Austria — a future-oriented model house for sustainable construction with Porotherm clay blocks. The e4 BRICKHOUSE 2020 meets the requirements of the EU's energy performance of buildings directive for 2020 (Directive 2010/31/EU).

With an integral approach to buildings, the comprehensive approach of the e4 BRICKHOUSE concept is based on four key factors: a massive energy-efficient building envelope made of clay blocks, renewable energy sources, affordable construction and energy costs, and unique living quality.

Heimo Scheuch, CEO of Wienerberger AG, explained: "Our vision includes energy-efficient and sustainable buildings that are attractive and affordable. With the Wienerberger e4 BRICKHOUSE concept, we are demonstrating the realization of this vision with our clay blocks."

Scheuch added: "Even the best theory is useless if it can't be proven, and now we want to provide this confirmation. In Zwettl, Lower Austria, we are building Europe's first e4 BRICKHOUSE 2020. This model house will show that innovative, energy-efficient and sustainable but, above all, affordable buildings for tomorrow can be built today with natural ceramic building materials."

This near zero energy house made of clay blocks already meets the requirements of the EU's energy performance of buildings directive for 2020. According to this directive, a nearly zero energy house is a building that covers most of its low energy requirements with renewable energy sources. Therefore, the goal of this project is not only to minimise energy requirements for heating, but to also maximise the overall energy efficiency and to keep the primary energy demand and CO2 emissions of the house as low as possible. In order to meet these goals, the building envelope and the heating and building technology must work perfectly together.

The house was built with the Porotherm infill blocks CLIMAmur 42, the newest generation of Wienerberger blocks with integrated thermal insulation. They combine the natural building material of clay block with the mineral insulating material rock wool. The massive building envelope of high thermal insulating blocks guarantees excellent heat protection and high thermal accumulation. It protects the interior rooms against heat in the summer and keeps the building pleasantly warm in the winter — and all that without extra cooling or too much heating. This keeps energy demand low throughout the entire year.

In its buildings directive for 2020, the European Union points not only to the energetic optimisation of buildings, but also to cost-effectiveness — in other words, affordability. This factor was given special attention in the planning and realisation of the e4 BRICKHOUSE 2020. Consequently, one of the goals was to keep construction costs and, above all, operating and maintenance costs down. This house demonstrates sustainable and lasting values.

Stellaria NZ Ltd is currently building an equivalent home using the Porotherm R25Th+ block. NZ's e4 BLOCKHOUSE endorsed by Wienerberger, will be monitored for energy efficiency and overall performance for a period of one year.

Exceptional Fire Performance with Porotherm Clay Blocks

Porotherm Clay Blocks are a naturally fire resistant cladding and structural solution for residential and commercial projects, including inter-tenancy walls.

In New Zealand interior wall materials in certain situations require a Group 1-S rating to comply with the NZ Building Code. The Group Number is a numeric representation of the performance achieved during the test and is used as a standardised benchmark for the assessment of surface finish performance. The Group Number requirements are repeated within the Acceptable Solutions C/AS1-C/AS7 relevant to each risk group.

The fire test procedure for establishing the Group Number is based on either:

  • ISO 9705, which is a full-scale room corner-test, or
  • ISO 5660, which is a bench-scale fire test on a small sample of the material.

In Australia and Europe, the same general hierarchy of risk for surface flame spread for finishes is used. While differences exist in the small-scale or intermediate-scale fire test methods adopted in the different jurisdictions, the resulting classifications are considered to be sufficiently similar to the Group Number requirements of NZBC Clause 3.4(a), such that the results can be used directly for the purpose of compliance with Clause C3.4 of the New Zealand Building Code.

In addition, materials used in exterior walls of residential buildings over 10m or commercial buildings over 7m require fire testing.

In Europe, the reaction to fire of construction products and materials are classified using the criteria and test methods described in EN 13501-1. There are five classification levels A1, A2, B, C, D, E and F (from least to most combustible). Porotherm clay construction block rates A1 and has been independently tested by Lucideon (formerly CERAM), one of the world's largest industrial testing laboratories and Exova Warrington Fire — one of Europe's foremost fire testing and certification companies. In the CERAM test, a 100mm load bearing wall remained structurally intact after a two hour fire test — making it an ideal option for boundary walls. Porotherm block walls achieve a Class A1 fire rating.

In the event of fire, Porotherm Clay Construction blocks do not burn, do not produce smoke and do not generate harmful gases. Both during and after construction, a Porotherm wall is totally fire resistant. So, in terms of Group 1-S fire rated products for both internal and external walls, Porotherm solid-plastered structural clay blocks, tick all the boxes.

These exterior wall construction and internal wall blocks are 100% organic, kiln-fired at 1200°C and rated at Group Number 1-S according to NZBC Clause C3.4(a) using ISO 9705:1993, Australian NCC Specification C1.10 Clause 4 using AS ISO 9705:2003 and the European classification using EN 13501-1:2007.

For apartments and inter-tenancy walls, Porotherm is a perfect fire resistant solution, and being part of the 'Fabric First' approach to building, the substrate itself is already safe. No added elements or products required — it's simple, easy and completely fire resistant. 

Designing Intelligent Buildings

Smart materials and systems that create high thermal, acoustic and ventilation performance are key to intelligent building design.

Intelligent buildings are those in which the building fabric, space, services and information systems can respond in an effective manner to the demands of the owner, the occupier and the environment. The result is a sustainable, responsive, effective and supportive environment where individuals and organisations can achieve their objectives. Technology is fundamental, but is an enabler rather than an end in itself.

The Intelligent Buildings International (INBI) journal is a fantastic resource on this — going beyond traditional engineering and architecture solutions to examine new methodologies and tools for intelligent buildings, smart materials and systems.

An example of an intelligent building is '2226', designed by Austrian architect Dietmar Eberle, using Porotherm clay block. The building was designed to work without heating, cooling or a mechanical ventilation system — almost everything usually considered indispensable for maximising comfort in multi-level buildings.

The sole sources of heat are present in the building fabric, the building's users (on average a person emits about 80 watts in thermal energy), and office equipment and appliances such as PCs, photocopiers and coffee machines. The necessary temperature stability is ensured first and foremost by its thermal storage or mass using Porotherm clay blocks.

In '2226', the Porotherm walls have been given a smooth, breathable lime plaster finish on both sides to ensure breathability and pure indoor air quality. The triple-glazed windows with their completely insulated frames are also a proven element in the construction kit — '2226' has no heat recovery ventilation system. Instead the architects opted for window-based, or rather, shuttered aeration.

While luxury is seen in the thick block walls and generous interior spaces for good ventilation — and would be considered out of the question for downtown investment projects where every rentable square metre is measured — '2226' was not expensive to build. The costs of materials required to achieve greater thermal mass and longevity were offset by dispensing with technical equipment.

Porotherm is a highly intelligent, technologically-advanced building system, specifically designed to self-ventilate while also managing moisture, temperature and sound. It is a high performance walling solution suitable where the complexity of integrated building design demands increasing technology and energy efficiency.

As an apartment or office building fabric, Porotherm also provides added acoustic, fire-proof and low maintenance benefits.

'2226' is a simple building where modern technology meets the 20th century. Like so many other simple buildings, it is the result of thoughtful planning. The building is a much-visited object of identification for architects and construction professionals in a day and age where regulations and constraints give rise to a longing for simplicity, and a growing appreciation of more intangible values.

By Chris MacPherson - Published on Eboss

Clay Blocks Speed Up High-Density Residential Construction

Wienerberger's Porotherm clay block walling system has been used to accelerate the construction retirement apartments by McCarthy and Stone.

The apartment building consists of 32 one and two bedroom apartments, and is the third apartment block by McCarthy and Stone to make use of Porotherm in the West Midlands region. Although not originally designed and planned as a Porotherm project, the system presented the opportunity for quick construction. It was specified by McCarthy and Stone, working in conjunction with EH Smith and Wienerberger.

Block work commenced on site at the end of March, followed by roofing works at the beginning of April. Six weeks were allocated to roof the project, compared to an average of 16 weeks using traditional methods. The quick speed of the build also allowed the builders and contractors to progress with its internal aspects earlier than would be traditionally expected.

Porotherm clay blocks are specifically designed for multi-level use and inter-tenancy walls for acoustic, thermal and moisture management, making them ideal for a range of high-density residential projects. No risk of fire, mould or deterioration ensures a long term investment for building owners. 

Porotherm clay blocks also meet consumer demand for more efficient products to reduce energy and resource consumption. In Europe, Ecodesign, energy labelling and the EU's 2020 energy efficiency objective support industrial competitiveness and innovation by promoting the better environmental performance of products throughout the internal market. In New Zealand, the Green Building Council's Homestar ratings have a similar objective.

New Zealand's population is growing and land continues to be used for unsustainable urban sprawl. Many councils and local bodies are attempting to encourage urban density in the same way European cities have been doing successfully for hundreds of years. To develop sustainably, New Zealand has to look at those who are already doing it and how.

The Auckland Council Unitary Plan is one such attempt to encourage the development of better land use. At one point it also encouraged builders/developers and homeowners to collaborate with the New Zealand Green Building Council to achieve a Homestar level 6. It is highly unfortunate that this is not being followed as it was the only benchmark NZ had to raise the performance level of homes. NZ's authorities should be encouraged to follow the lead by global initiatives to establish sustainable growth.

The critical element is choice of building materials. It's very encouraging to see more and more New Zealanders doing their own research in order to meet long-term requirements of durable and sustainable housing. It is painfully clear that building to the minimum code requirements and using materials susceptible to deterioration if moisture is present provide short-term solutions that will be more costly to fix and replace in future. By selecting sustainable, long-lasting products such as Porotherm Clay Blocks, healthy sustainable housing can be built.

Attractive Terca Clay Bricks Enhance Energy-Efficiency

The Wienerberger Brick Award highlights how durable, environmentally-friendly clay bricks can make an important contribution to the energy-efficiency of homes.

One of mankind's oldest and most durable building materials, brick offers countless design possibilities. Available through NZ partner Stellaria, Wienerberger bricks are timeless and innovative — especially when used in modern, future-proofed architecture. These durable, environmentally-friendly, clay bricks make an important contribution to the energy-efficiency of buildings. 

Held every two years, the Wienerberger Brick Award put bricks into the spotlight, demonstrating how architecture using brick can be modern and exciting. Applications for the award range from building solutions using classic clay blocks, facing bricks and roof tiles, to the creative application of clay pavers and ceramic facade panels.

The Brick Award promotes excellence in buildings constructed using clay products based on criteria including sustainability, energy efficiency, functionality and innovative exterior design. It is an independent award; the use of Wienerberger products is no decisive factor for participation.

From all submissions worldwide, an independent panel of architecture journalists and critics narrows down the number to a total of 50 projects, which are nominated for the Wienerberger Brick Award in different categories. Subsequently, an international jury of architects selects the category winners, as well as one grand prize winning project.

The Brick Award acknowledges innovative brick buildings of international quality that show the varied and diverse ways brick can be used in contemporary architecture. At the same time, the award — and in particular, the accompanying architectural book — gives experts and people with an interest in architecture an overview of current developments and trends in international brick architecture, with its remarkable range of applications.

Images above show House 1014 by Harquitectes, Spain, one of 2014's Grand Prize winners. The home features Porotherm blocks, Penter pavers and a Terca Brick facade. A recent New Zealand project featuring Terca Clay Facing Bricks is also shown. 

A Rigorous Peer Review of Porotherm's Clay Block Construction for NZ Seismic Conditions

Structural engineer Dr Jason Ingham compares Eurocodes 6 and 8 with the limit loading criteria in the New Zealand Building Code.

The Porotherm confined masonry system has been peer reviewed by one of NZ's most recognised structural engineers, Dr Jason Ingham. Jason explains how Eurocodes 6 and 8 are consistent with the limit loading criteria specified in NZS 1170.5. and the design philosophy is consistent with NZS4230.

"Confined masonry is a building system that is not widely used in New Zealand and for which we have no national design guidance. However, confined masonry is promoted in many other parts of the world in recognition of its proven satisfactory earthquake performance when designed appropriately. Most importantly, confined masonry is a codified construction technique in Europe, where its use is incorporated into Eurocode 8 "Design of structures for earthquake resistance" and Eurocode 6 "Design of masonry structures". In these Eurocodes there are no limitations placed on the level of seismicity that the confined masonry system can be designed to sustain.

The loading applied in the design procedure for Porotherm is consistent with the limit state loading criteria specified in NZS 1170.5. The design philosophy adopted for the design of Porotherm is consistent with the philosophy of NZS 4230 in that the European approach to partial safety factors using a ratio of (1/1.5) is directly analogous to and mathematically consistent with the New Zealand approach of using a strength reduction factor of Φ = 0.75.

The design of Porotherm Clay Construction Blocks has been undertaken using two approaches. In the first approach an equivalent static design has been developed using the European factor q=2 which effectively corresponds within NZS 1170.5 to the ratio k_μ⁄S_p . The factor of q=2 recognises that confined masonry in effect has limited ductility, rather than being brittle. This value is codified into the Eurocodes and is well supported by technical literature and physical testing evidence. This methodology and the design shear strength for confined masonry have been used to establish that the inplane response of the walls, appropriately accounting for torsion effects, exceed the design base shear demands.

The equivalent static analysis has been supplemented with a nonlinear pushover analysis using custom-written software developed in Europe specifically for the confined masonry system being used in this project. Within that software I confirm that all country-specific variables have been matched to the corresponding New Zealand-specific spectra. The design calculations provide further documentation to show that when subjected to design level earthquake loading, the building loads and deformations are well below those corresponding to ultimate limit state strength and drift levels.

The out-of-plane analysis of the gable ended wall has been undertaken accounting for parts loading, consistent with the standard procedure adopted in New Zealand when assessing unreinforced masonry walls responding out-of-plane. The capacity of face loaded walls has been determined using the codified EN 1996-1- 1:2005 + A1: 2012 Annex A procedure, and explanatory text has been provided to explain this procedure.

The detailing associated with the reinforced concrete boundary elements is consistent with Eurocode requirements for spacing of confining elements and the detailing of reinforcement within these confining elements, with supplementary strength checks for elements such as lintels having been undertaken using design software provided by the Structural Engineering Society of New Zealand."

By Chris MacPherson - article first published by Eboss

Declare: Increasing Transparency for Healthier, Safer Buildings

Declare accreditation for Porotherm confirms that it is a 100% natural and sustainable product, suitable for NZ's built environment.

Wienerberger's Porotherm Clay Block R25Th+ has recently been granted the Declare label. Approximately 149,000 houses are built with Wienerberger products in Europe every year. The most striking feature of Porotherm Clay Block is that it is 100% natural with just three essential ingredients — clay, sand and lime. It breathes. It uses 90% less water, will last well beyond 150 years and can be crushed back into your garden. With 230 manufacturing plants globally and over 200 years since Wienerberger was founded, Porotherm boasts a long list of product and performance labels under rigorous testing criteria. Declare is its latest acquisition for the NZ market.

Declare is the brainchild of the Living Building Challenge under the umbrella of the International Living Future Institute which was founded in the United States. As stated on the Declare website: "The Living Building Challenge is the world's most rigorous proven performance standard for buildings. People from around the world use this regenerative design framework to create spaces that, like a flower, give more than they take."

It is a specific tool designed to enable architects, designers and specifiers to research how their choice of building materials will impact the building's occupants, as well as the environment. Architects and specifiers have immediate access to the list of ingredients and levels of toxicity in building materials.

This global trend towards transparency through accreditation and certification is a growing pre-requisite towards sustainable business practice and the promotion of wellness for ourselves and our environment. Certifying the whole building as well as individual building materials is gathering momentum globally and catching the attention of many recognised NZ organisations.

In Europe, the Energy Performance of Buildings Directive requires all new buildings to be near zero-energy by the end of 2020. All new public buildings must be near zero-energy by 2018. Should a similar requirement be extended to the use and restriction of chemicals in all building materials?

Declare is a transparency tool designed to encourage a healthy building economy based on non-toxicity and social equity and is the most recognised sustainability accreditation for the built environment in today's construction market. All materials must contain none of the toxic substances on the 'Red List'. The use of regenerative materials is an essential element in sustainable building.

The concern around high levels of toxicity in New Zealand building materials is well documented and ongoing. Sustainability and the eco movement is not just about environmental impact; Health statistics from well recognised research institutions are being released on a regular basis exemplifying the ill effects some of our buildings are having on our health.

Declare is the only rating tool addressing the issue of chemicals — should this become a standard requirement in NZ as well as the assessment of environmental and energy impact on the built environment?

BRANZ has developed, an independent research, testing, consulting and information company for the NZ construction industry. Under 'Health and Safety' on the Level website, BRANZ outlines how to take care with materials, equipment and work procedures and dealing with hazards stating that while "timber treatment prevents deterioration... Unfortunately, the chemicals used to preserve timber can also be harmful to people."

BRANZ recommends building site teams obtain safety data sheets from the producer or supplier of treated timbers and provide information on how to store, use and dispose of the timber which usually contains red-listed compounds. While many worldwide organisations are attempting to address the issue of chemicals in building materials – demand is driving its continued use without any real and immediate solutions for alternatives.

Declare's standout point of difference is the transparency required for consumers to immediately see the Red List of chemicals used. It also shows where a product is manufactured and ingredients sourced, VOCs, product durability and its expected recycling pathway.

Porotherm & Declare!

We have something to declare! Our Porotherm R25 Th+ Blocks are now Declare Certified!! You may be scratching your head wondering what this means, a Declare Label answers three questions:

1. Where does a product come from?
2. What is it made of?
3. Where does it go at the end of its life?

Declare is a transparency platform and product database that is changing the materials marketplace. Declare is the initiative of the International Living Future Institute, which are premised on the belief that providing a compelling vision for the future is a fundamental requirement for reconciling humanity’s relationship with the natural world.

Our Porotherm Blocks are simply made of Clay, Limestone and Sand, making them 100% natural and nontoxic. Any leftover bricks or wastage can be crushed and put back into the ground, and the blocks themselves have a design lifespan of 150 years with a material lifespan well beyond that. 

Trending Quality & Durability

Hi Everyone,

In this newsletter we would like to tell you about our recent trip to Europe in temperatures well below zero and how magnificently Europe's buildings perform! While we are glad summer has at last arrived in NZ, it was fantastic to experience the extreme cold outside and complete warmth of every building we entered. 

In working with our European partners, our focus is on the ultimate building performance from each stage of the manufacture of construction materials through to every level of construction - ensuring quality & time-tested durability. 

We hope you will enjoy reading a small account of some of our partners we visited and a snapshot of why European technology remains amongst some of the most trusted globally and the growing presence they play in the construction industry especially around sustainability & energy.

On the home front we are very excited to let you know we have been granted DECLARE accreditation for our POROTHERM Clay Blocks. 

To celebrate our highly valued European connections, please find the special invitation below to attend an Italian made Expo in Auckland on Valentine's Day! You will see some of Italy's most prestigious cars, motorbikes & products while enjoying the best of Italian wines & food...

Thank you for receiving this newsletter - we hope you will enjoy reading as much as we do putting it together...we apologise if you have received this in error. Please send us your feedback and don't forget to RSVP your attendance to the Expo. See you there!

The Stellaria Team

Our first stop...the Silber Joinery manufacturing plant in Wels, Austria. Fabulous joinery using some of Europes' best timbers/aluminium and/or copper bronze exterior options. Silber mostly produce luxury joinery for specialist projects worldwide  Joinery of this calibre has an average R-value of 1.6 ensuring our POROTHERM Clay block buildings can easily meet require zero energy requirement. Read more...

A cross section of how easily the joinery is installed into the POROTHERM clay block system ...

Next we visited Internorm in Graz, Austria. The smallest of 3 plants in Austria producing over 8 million pieces per year for the global market. Again with an average R-value of 1.6 Timber/Aluminium or UPVC (coloured) for the interior, Internorm is Europe's No'1 producer. Read more...

Then we visited Diesl solid timber flooring in Leizen...beautifully warm with floor to ceiling triple glazed windows inside and below zero temperatures outside! Idyllic backdrop of snow covered mountains, the manufacturing factory next to this gorgeous showroom produces world class solid flooring. We were very pleased to visit! See more...

Last stop...visit to the Strasbourg Wienerberger manufacturing plant and a block-laying demonstration with Jean-Claude. Wienerberger conduct regular training sessions at their various plants in Europe - our clients very much enjoyed the experience! Overall - a fantastic visit!

Exposed Porotherm Walls

We get a lot of people asking if the have to cover their Porotherm walls, the answer? No way! Porotherm clay blocks create a warm, and comfortable environment but also look beautiful. Check out this beautiful office in Copenhagen with exposed Porotherm walls. 

Find the full article here...

White Brick Inspiration

We love this 'Mews House', situated in London. Marziale brick has been used both internally and externally to create a beautiful spacious home. 

In the courtyard a small niched area is incorporated into the brickwork wall for residents to place candles or herbs and plants to enliven the courtyard place. How beautiful!

See the full article at Arch Daily  - Photos by Rory Gardiner 

A Low Tech Approach to Energy Saving with Porotherm Clay Blocks

Featuring solid Porotherm Clay Block walls, the six-storey '2226' house ensures that temperatures will remain between 22°C and 26°C.

While buildings require less and less energy, more and more is being spent on the maintenance and service needed to sustain this reduction. The prospect of buildings functioning as mini power stations is highly reminiscent of the promises of Modernism.

More comfort with less energy '2226' is an archetypal sustainable building. The basic idea is to achieve an extraordinarily high level of comfort whilst using as few technical systems as possible. As a result, the six-storey building does not require any heating, cooling or mechanical ventilation.

Architect Baumschlager Eberle focused his attention on reducing to a minimum the number of elements within the building that require costly maintenance and technical servicing and relied instead on solid Porotherm Clay Block walls and the air-cleansing effect of lime, high ceilings and large room depths, elegant materials, effective air circulation and the optimum use of daylight.

The building is named '2226' expressing exactly the temperature range — between 22°C and 26°C which the indoor climate is designed to arrive at by totally natural means. In other words, the new building is basically a passive house in the original and actual meaning of the word.

The necessary temperature stability is ensured first and foremost by an enormous thermal mass: the outer walls consist of 76cm thick brickwork, divided into an inner, 38cm thick layer of load-bearing vertical coring bricks and a further 38cm of insulating bricks with a high percentage of core holes — specifically for the European winter.

The six-storey building has a square-ish plan with centrally located structural core walls forming a pinwheel configuration that divides the internal spaces. Floor heights of 3.5m and the vertical orientation of the windows ensure natural light reaches deep into the spaces.

External walls are constructed with two layers of masonry block, each 36cm thick, and are rendered externally and plastered internally. The specified masonry units are from Wienerberger's Porotherm range of hollow clay blocks. These are laid with 1mm bed joints and, due to their interlocking plan shape, no perpend joints.

Insulation is only used for the floor and roof slabs; the air pockets within the clay blocks provide the walls' thermal resistance. Both skins of block are in Porotherm, although the specification differs to provide greater strength to the inner skin and greater thermal efficiency to the outer skin. The building has no heating, ventilation or cooling system, the flow of energy being controlled by human hand.

Stellaria NZ currently has several projects across NZ at varying stages of planning/construction to achieve this exact same result — '2226'. Stellaria's buildings use single-skin Porotherm R25 Th+ with triple glazed windows by Internorm, and will meet an energy requirement of 7kw/m²/a. Passive house criteria is 15kw/m²/a.

Working with thermal and Sound Engineer, Lubos rajci from Soundtherm, New Plymouth, NZ's Porotherm houses will provide all year-round comfort and ventilation with minimal heating and cooling — everyday appliances and human activity will be sufficient to heat these homes.

Compliance with NZBC Clause H1 Using Clay Construction Blocks

A modelled method on a proposed five level contemporary home being constructed using good passive solar design and clay construction blocks.

This article is about a modelled method on a proposed five level contemporary 520m² home being constructed in R25Th+ Porotherm clay construction blocks, concrete floors and concrete roof structure. There is no timber framing or other timber construction element in the building.

This describes not only the compliance with Clause H1 of New Zealand Building Code (NZBC), but also much higher energy-efficient design using good passive solar design — incorporating appropriate areas of glazing, orientation and thermal mass. In combination with a well-insulated thermal envelope and reduced thermal bridges, an efficient use of energy minimising heating and cooling costs will be easily achieved.

This use of good passive solar architectural design and energy-efficient performance of Porotherm is not just about compliance documentation for territorial authorities, but is a living philosophy achieving generational sustainability, comfort and high level indoor air quality.

To achieve compliance with Clause H1, a building must be constructed to facilitate efficient energy use for functional requirements (e.g. modifying temperature, providing hot water and artificial light) and to provide an adequate building envelope performance to minimise energy loss.

The general requirements on energy efficiency of housing and small building envelopes is described in New Zealand Standard NZS 4218:2009. This standard specifies the following three different verification methods to demonstrate compliance with Clause H1:

SCHEDULE METHOD                                                                                                            

  • Glazing area is 30% or less of the total wall area              
  • The combined area of glazing on the East, South and West facing walls is 30% or less of the combined total area of the walls
  • The skylight area is no more than 1.5m² or 1.5% of the total roof area 
  • The total area of decorative glazing louvres is 3m² or less.


  • A glazing area greater than 30% but less than 40% of the total wall area 
  • A reduction in the construction R-Value of some building elements if this is compensated for by increasing the construction R-Value of other building elements.


  • May be used for any proposed building design and all buildings where the glazing area is more than 40% of the total wall area.

The proposed new dwelling will be in Climate Zone 2 and will be constructed with high thermal mass Porotherm walls. To demonstrate the compliance with Clause H1, R-values listed in Table 1 will be achieved. 

NZS 4218:2009 does not distinguish the R-Values for types of floors against different exterior conditions such as ground, ambient or unheated spaces. Therefore, we applied the same required R-Value for all types of floor in any proposed building.

From Table 1, we can see that the proposed building elements easily achieve the required minimum R-Value for Climate Zone 2 using the Modelling Method.

Furthermore, the proposed building demonstrates an excellent passive solar design incorporating appropriate areas of glazing and solar orientation. The glazing area is more than 40% of the total wall area and therefore the Modelling Verification Method was used.  

The calculation method follows the European Standard EN 13790 and demonstrates a heating energy demand of this proposed building at 9 kWh/m2a. The upper limit for the specific annual heating demand for Passive House certified buildings is 15 kWh/m2a. To design the heating system the calculated heating load of 10 W/m² is used.

The extent of the glazing in this design creates overheating (>25°C). An active cooling system or solar shading has been specified. This overheating is controlled by exterior louvred shading and passive cross ventilation incorporating a  three level stairwell and tilt-in joinery units. The design has resulted in zero energy demand for cooling which minimises the total annual energy demand of the building.  

Using the reference building R-Values according NZS 4218:2009 in the same modelling method this building in timber frame results in a heating energy demand of 123 kWh/m2a.

Based on our calculation, we can conclude that the proposed building easily achieves the requirements of New Zealand Building Code Clause H1. This building will easily meet and exceed Passive House criteria. 

See the design over at MacPherson Architecture or on our site under 'In Progress'


Meet the Team!

Our team is getting bigger! Meet Fede & Katie. Fede joins us from Argentina. He studied Architecture at the Universidad Blas Pascal (Argentina), is interested in learning new technologies and to keep growing as an architect. He's a photography enthusiast who enjoys outdoor activities like tramping and biking.

Katie has actually been with us since February! She's our Marketing Assistant and now a certified Homestar Practitioner. She's incredibly passionate about environmental sustainability and is currently work toward her Masters in Environmental Management. They have both brought a lot of enthusiasm and extra noise to the office!


Over Heating - How Solar Passive Design Reduces Risks

The spotlight's currently on climate change, with ‘Before the Flood’ being released and the Paris Agreement coming into effect this month, we all know temperatures are on the rise. Again, this year is predicted to be the hottest on record. Heatwaves can have detrimental effects on our elderly and cause a death spike.  So what does this mean for our homes? It has been seen already in Auckland, that even new apartments will not be able to handle the energy load to run air-conditioning units (read the article here). The densifying of Auckland and our main cities will also heat things up. Keeping homes warm wont be the only priority - we must be able to keep them cool as well. 

The absolute necessity for passive solar design, not only for heating but for cooling as well, has never been so important. Lets look at the factors influencing overheating in housing… (this little inforgraphic comes from the Zero Carbon Hub – UK)

Considering overheating at the design stage will ensure cost savings however it often isn’t even discussed. With the focus being on warm dray housing taking priority. Details which help reduce the risk of overheating include exterior shading. Shading the windows reduces over heating in warmer months, this can be done in a number of ways, such as foliage, fixed over hangs and roller blind or adjustable louvres. Glazing that faces east or west poses a bigger challenge. Overhangs do not work when the sun is low, therefore louvred shutters or roller blinds that cover the whole window are required. We love these European Louvres from Griesser

These shutters can all be on sensors, based on temperatures, wind or rain. They do the thinking for you! 

Building Half a Good House with Stellaria

After months of planning, NZ's first e4 home — designed to more than double in size with minimum cost — is being built in New Plymouth.

With New Zealand facing three major issues in housing — leaking homes, affordability and availability — Stellaria has been inspired by Wienerberger's global approach to meeting housing demands and has tailored its very own e4 house for the NZ market. After months of planning, the first e4 home in New Zealand is being built in New Plymouth.

The home is simple, fast and energy-efficient. Constructed in Porotherm Clay blocks, it is designed to more than double in size with minimum cost when the family grows or when adding an extension becomes more affordable. In the meantime, there is plenty of available storage area. The potential to expand within the superstructure provides an attractive 'future-proofed' home.

Stellaria has most recently been inspired by Chilean Architect, Alejandro Aravena who won the 2016 Pritzker Prize by releasing his designs as an open-source resource to help tackle the global affordable housing crisis. Alejandro has championed an approach he describes as 'incremental' in which governments fund construction of 'half a good house' with residents completing the other portion as resources allow.

It is Stellaria's belief that all New Zealanders should have access to high quality homes that are warm, dry, safe and 100% natural. On average, the e4 Blockhouse will save homeowners between $3-5k per year on energy and maintenance while providing the home with 100% pure indoor air quality, free from out-gassing and formaldehydes.

Homeowners will be able to build 'half a good house' first, enjoying a 106m² family home with a 2,750m stud height. The home will feature UPVC coloured joinery (R-value 1.6) manufactured in Austria, and solid lime plastered walls. When the homeowners decide to increase the floor plan, they will be able to achieve a total of 208m² of liveable space within the superstructure. As the superstructure with mid-span floor is already built — pre-wired and pre-plumbed — the cost of this extension is considerably lower than that of extending a traditional timber framed home (depending on the fit-out).

For the same price as a 140mm timber frame home with brick veneer cladding, the e4 Blockhouse is a far superior, high-performing home that will last forever. Add to that the near-zero running and maintenance costs, and this is an ideal building solution.

Construction Waste, where does it all go?

According to Level, (the authority on sustainable buildings in New Zealand, funded by BRANZ) 850,000 tonnes of waste is sent to landfills/clean fills yearly from construction and demolition alone. That’s some 141,000, 6-tonne African elephants. How’s that for perspective! Resulting in 8.5 million dollars in levy revenue per annum. 

We often don’t think about our waste, in to the rubbish bin it goes, and so disappears from our sight and consciousness - out of sight, out of mind. The same goes for the building industry, only the construction industry ‘rubbish bin’ is 10 times bigger! While we are incredibly lucky to have a lot of land here in New Zealand, space is quickly running out. It’s only a matter of time until waste levies and taxes are imposed. The current levy is at $10 per tonne of all waste sent to landfill. A small price for a lot of waste. The building industry has to get ahead of the game... 

But it doesn’t have to be this way, a large majority of construction waste can be diverted from landfills by having efficient and effective waste sorting procedures and the necessary allocated bins to do so. Waste reduction needs to be considered at the early design stage of any build.
A standard timber frame house, includes many components to the build and as a result a lot of potential waste. Stellaria’s e4 Blockhouse, has only two ‘touches’ to the wall – clay blocks and plaster. With the structural elements being pre-made steel and concrete - the end waste output is reduced considerably. 

Our first e4 block house has just started down in New Plymouth, and we will be keeping a close eye on our waste. We hope to report back on how much we can divert from landfill and clean fill - so watch this space! The goal is, to send less than 10kg of waste per m2 of gross floor area, to landfill/clean fill.  

Stellaria Construction Ltd is dedicated to sustainability, operating at a ‘cradle to cradle’ level wherever possible. This form of construction produces 45% less material waste and 95% less water waste. Being 100% natural, any off-cuts can be crushed back into the garden. We thrive on meeting every challenge to building sustainably! 

Check out NZGBC awesome introduction to Site Waste Managment