Cavity wall insulation is used to reduce heat loss through a cavity wall by filling the air space with material that inhibits heat transfer.
Cavity wall insulation diagram.
They can be described as consisting of two skins separated by a hollow space cavity.
Cavity wall insulation costs and savings.
Cavity wall insulation explained.
Cavity wall insulation makes it much more difficult for heat to pass through your walls by filling up the cavity with a material with lots of small air pockets in it.
This immobilises the air within the cavity air is still the actual insulator preventing convection and can substantially reduce space heating costs.
One function of the cavity is to drain water through weep holes at the base of the wall.
A specialist company will drill holes in the outside walls inject insulation through the holes and then seal them with cement.
Cavity wall insulation normally takes around two hours to install but this depends on the size of the house and other factors such as ease of access.
Many cavity walls can be insulated by injecting insulation material into the cavity from the outside.
In most wall applications you will use r 13 or r 15 kraft faced fiberglass insulation rolls for these two by four stud walls.
The skins typically are masonry such as brick or cinder block masonry is an absorbent material that can slowly draw rainwater or even humidity into the wall.
While rated differently these two types of insulation are close enough in thickness that they can both fit into modern two by four wall systems.
These pockets are more efficient at reducing heat transfer by convection than the big air cavity was.