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earth blocks and mortar in the HGM earth and lime workshop show the visual benefit of building with earth in new build systems How we've used earth blocks as new build systems at the yard, they've become stairs to the office

Benefits of Building with Earth

Earth; a thermal battery for your house

The benefits of building with earth are not reserved solely for the ease of build or the effectiveness of the structure, they extend beyond the mere “bricks and mortar”. As well as providing the building blocks of your house, plasters, mortars and floor finishes the same earth also provides your home with thermal mass, creating a thermal battery for your home.

As your house heats up through solar gain or your central heating system the earthen materials also heat up charging the battery. When heat starts to flow out of your building, perhaps someone has left a door open or the heating has been turned off at night, the battery of heat starts to discharge into the room passively warming the space.

You are storing your heat in the walls not just the air. The result is a more even internal temperature through day and night and a reduction in heating loads.

“Unfired clay brickwork has been shown to provide passive environmental control in buildings through buffering of the temperature in the building (through the provision of thermal mass), and through buffering relative humidity by absorbing moisture from the air at high humidity, and releasing it at low humidity. Buffering of temperature and humidity will normally reduce the energy required to operate buildings.”

Dr Andrew Heath of the University of Bath

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Earth; Simple, Clever, Healthy

Simple earth;

Due to the requirements for better performing homes, building methods and materials have been getting more and more complicated. Mechanical ventilation systems, multiple layers of membranes, sealants and tapes are becoming the norm.

At H.G.Matthews we have been asking why does it have to be this way? Our natural building materials are taking it back to basics re-inventing one of the oldest building materials known to man; EARTH.

Our earth blocks and plasters are made from simple materials; clay rich earth and straw, but are also simple in their construction method. Any mason or block layer will be familiar with the process of laying them and any plasterer will be familiar with methods employed to use our plasters.

Prototype builds using these simple materials have shown that it is possible to reach PassivHaus standards of airtightness without the need for membranes, tapes or sealants.

Clever earth;

Unfired clay masonry has been shown to provide passive environmental control in buildings through the buffering of temperature and relative humidity.

As your house heats up through the heating system or solar gain the earth heats up and stores thermal energy. When heat starts to flow out of your building, perhaps the heating has been turned off at night, the stored heat starts to discharge into the room passively warming the space.

This creates a more even internal temperature between day and night and reduces the load on your heating system, decreasing fuel bills.

As you are storing thermal energy in your walls not just in the air, you can perform the required amount of air changes with fresh external air without losing your heat store. This makes cheap and simple natural ventilation a viable option.

Un-fired clay masonry performs the same role with humidity. During times of high humidity it will absorb the excess moisture from the air. During times of low humidity it will release the stored moisture back to the air. This keeps the internal humidity within the optimum range of 40-60% RH.

Un-fired clay masonry is such an effective humidity regulator that a research project ‘Low Cost Earth Brick Construction’ by Tom Morton and others has shown it to outperform, and render unnecessary, mechanical bathroom extract fans, all this with zero energy input!

Healthy earth;

Strock houses prevent the ‘sick building syndrome’. Unlike other construction materials which often contain or are coated with harmful substances such as volatile organic compounds, formaldehyde, etc., our earth building products are made of 100% natural materials and are free from such air pollutants. As a result indoor air quality in an earth house is very good and less likely to provoke allergies, tiredness and headaches among occupants.

Earth presents zero toxicity to builders, building inhabitants and, in the event of their disposal; the environment. They are healthy for you and healthy for the environment.

Earth passively regulates internal humidity keeping it within the healthy zone of between 40% and 60% RH. This decreases the risk of respiratory infections, inhibits mould formation and prevents condensation from accumulating.

Earth’s ability to passively regulate humidity and buffer internal temperature results in a stable indoor climate that does not require expensive mechanical ventilation systems to regulate. Natural ventilation becomes a viable option for earth houses saving you money and omitting health risks associated with the build-up of germs and bacteria in mechanical ventilation systems.

Building with Earth products; healthy for the environment

‘The UK construction industry is responsible for 32% of all landfill waste.’

We have addressed this industry wide problem by making our blocks from 100% natural materials. Our earthen blocks are made from clay rich earth and straw, both by products of H.G.Matthews brickworks and farms. At the end of their life, or any waste from site, can be composted and given back to the earth.

By utilising waste as a resource our earth building products reduce waste from the brickyard and have the potential to reduce landfill waste from the construction industry as a whole.

‘Total construction and demolition waste for England was estimated at 77.4 million tonnes in 2010’

Waste earthen building products don’t go to landfill, waste from a construction or demolition site can simply be composted or soaked, mix up and turned back into new earth products, reducing landfill waste.

‘Every year the Environment Agency responds to 350 serious pollution incidents caused by construction’

Our natural building products contain 100% natural materials and 0% toxic substances. There is absolutely no chance of them causing these sorts of incidents.

‘Construction materials account for 20% of the UK’s ecological footprint and 19% of the UK’s total greenhouse gas emissions’

Our natural building products are made from abundant natural materials. They do not require firing only drying. The innovative biomass dryers are fuelled by woodchips from locally sourced and sustainably grown trees.

They have extremely low embodied energy and have the potential to substantially lower the UK construction Industry’s ecological footprint.

‘Energy from fossil fuels consumed in the construction and operation of buildings accounts for approximately half of the UK’s emissions of carbon dioxide.’

As well as having extremely low embodied energy, Strock houses have very low energy requirements in use.

Strocks combined with woodfibre solid wall insulation creates a unique build system of thermal mass cloaked with a ‘tea cosy’ of insulation.

The blanket of Warmshell eliminates cold bridging and the thermal mass provides a bank of stored heat decreasing stresses on the heating system and passively warming the internal space when the heating is off.