Materials

Use of Materials / Construction Methods with Low Embodied Energy:

• Low embodied energy materials

• Earth-sheltered buildings.

• Low embodied energy materials

Many buildings require large amounts of cement for mortar and concrete.

The manufacture of cement requires a lot of energy so buildings that use cement have a high embodied energy.

Alternative materials that have lower embodied energy values are available

What are the alternative materials?

• Limecrete. Limecrete has half the embodied energy as concrete

• Rammed Earth

• Straw

• Earth-sheltered buildings

During cold weather, the ground is usually warmer than the air and the flow of the air over a building increases heat loss

Why are Earth sheltered buildings pretty dece?

Sinking some of the building into the ground can reduce heat losses.

Use of Materials with Low Thermal Conductivity / Transmittance?

• Double/triple glazing.

• Low emissivity glass.

• Vacuum/inert gas double/triple glazing.

• Wall/floor/roof insulation.

• Double/triple glazing.

Multiple layers of glass with spaces between them reduces the energy loss through windows

• Low emissivity glass.

This type of glass has a surface coating that reflects long wavelength infrared energy back into the building.

• Vacuum/inert gas double/triple glazing.

A gap between the panes filled with inert gases is more expensive but it has lower thermal conductivities

What’s the issue with wide vacuum gap in glazing?

It is not practical to have a wide vacuum gap because the panes need to be held apart with spacers which cannot be long, so vacuum double glazing is used where there is not space for gas filled multiple glazing.

• Wall/floor/roof insulation.

Most insulating materials reduce conduction by trapping airspaces in a porous structure

What do the most effective insulating systems have?

Prefabricated boards with a reflective foil layer to reflect infrared radiation.

Low environmental impacts of insulating materials

Some have low environmental impacts because they’re manufactured from waste, such as straw.