Sustainable Living: 3M FuturewiseTown PlanIntroductionGo BackGo Next: Convection3M

Front of school building

Back to front of school building

2. Wall

Stop convection currents in wall

To stop convection currents from happening in the cavity of the wall, insulation materials can be put into the gap to trap the air in small pockets. In new buildings, this insulation can be thick layers of sheep's wool, blocks of cellulose fibres (which is like a very thick cardboard or crumbly wood) or glass fibre wool (which is made from really thin strands
of glass).

In existing buildings, it is harder to fit cavity insulation as the walls can't be taken down to get to the gap.

So holes are drilled into the walls at regular intervals and then a special foam is sprayed into the cavity.

When the foam sets, it has captured lots of air bubbles
and so reduces convection currents.