The LAROS Method of Passive House Prefabrication

What is Passive House Prefab?

Passivhaus design is a collection of design principles that are used to create buildings which are thermally stable, comfortable for occupants and are highly energy-efficient regardless of weather conditions.

Rather than retrofitting energy-saving products to a traditional build, Passivhaus allows for this within the building structure, through insulation, airtight seals and membranes that don’t exist in unison in traditional building design. This decreases the need for heating and cooling before energy-saving solar is even introduced.

LAROS Structures uses prefabricated wall and roof panels that we build in our factory. Prefabrication allows for more efficient build times compared to traditional building methods, with wall and roof panels prebuilt and delivered to site ready for install. This limits onsite weather delays in build timeframes, as well as ensures precision measurements to ensure airtightness.

What makes LAROS different? The healthiness of our builds

LAROS passive house designs are built for health both for the occupants and the building itself.
We have a focus on health rather than performance, but high-performance goes hand in hand with healthly building practices.

There are many aspects of our design methodology that create a healthy home. The top three reasons of how we create healthy homes and what LAROS protect against are below.

Mould and Damp

Mould and damp has a huge negative impact on the health of occupants, and the home itself.

We use Pro Clima Wraps in our wall and roof structures as airtightness & moisture control membranes. These wraps provide excellent airtightness and weathertightness as they protect against external and internal moisture build-up and hence protect against mould and mildew, creating a healthy home. These wraps create a draught-free environment and are vapour permeable, allowing for outward drying of any moisture that does get into the building structure.

Pro Clima wraps form the 3rd piece of a LAROS Structure, sitting between wall insulation and external cladding. Ventilation systems and WUFI modelling before construction also ensure that no moisture can build up within walls and roofs, to the point that no condensation can form, and no mould or rot can form.

Air Quality

The use of mechanical ventilation in Passive Houses allows for greatly improved air quality inside your home. Filters can stop pollutants from outside coming in, and consistently flowing fresh air inside helps to reduce the buildup of CO2, VOCs, and viruses.

Not only do filters stop pollutants from coming in, but ventilation also helps to remove pollutants from your home – including smoke, cooking odours, moisture and indoor pollutants.

Safe Temperatures

Research indicates that sleeping in low temperatures at night can have a detrimental impact on our health. The World Health Organisations recommends homes to be at or over 18 degrees Celsius for a “safe and well-balanced” indoor temperature. Passive home design keeps heat in and requires less energy to stay warm, keeping us healthier at night.

LAROS design ensures safe temperatures within our structures through thermal insulation and thermal bridge free construction.

  • Thermal InsulationContinuous insulation is important in providing a thermal separation between outside and indoors. Careful installation and precision panel sizes are needed to ensure that there are no gaps in the structure so that the home is sealed from outdoor airflows.
  • Traditional InsulationThe 2nd of 4 parts of our wall panel structure is made from Earthwool® Insulation. This insulation is made from up to 80% recycled glass that is bound together using a biobased technology. In line with building a healthy home, this insulation is non-combustible, odourless, rot-proof, will not absorb atmospheric moisture, does not sustain vermin and does not encourage the growth of mould, fungi or bacteria.
  • Thermal Bridge Free ConstructionWell insulated homes make sure that insulation is continuous and that any penetrations through home insulation are kept to a minimum. LAROS do this through using low thermally conducting materials. When these are applied correctly, there aren’t any thermal bridges where heat can escape from your home.

Through ensuring high quality air, consistently safe temperatures and the prevention of rot and mould, LAROS home designs provide a safe structure for all inhabitants.


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