SEAI offers special grants for up to Euro 400 to meet your home improvements by cavity wall insulation. The installations need to be carried away by qualified installers as special tools are required to carry this out there. Under no circumstance this is a DIY job even for a person good with their hands.
A new cavity wall can be a wall insulation construction of two walls with an air gap in between or a wall constructed of hollow blocks. The air gap this way should be continuous for almost any effective tooth cavity wall insulation to be carried out.
The cavity wall insulation is applied in many ways with regards to the type and construction of wall structure, kind of insulation selected etc. What ever the material selected the idea is to cut off heat move by cutting off the heat transfer primarily, by conduction (ie. by physical contact) and convection (ie. by the movement of hot air (molecules) because of to air currents). Obviously unless there is a continuous cavity this process has limited detrimental affect as the heat by air movement is restricted to a tiny wall cavity section. (The conduction though not hindered in this but is a slow reaction).
There are several insulating material products that can be used for cavity wall insulation. Popular materials include Glass fibers, rock wool, expanded and extruded polystyrene (EPS and XPS) panels and beads and cellulose material. Even though cellulose material is not very popular here in Ireland, in some nations around the world such as USA it is widely used as it has a high R factor (at least initially), low price to make using recycled material and it is therefore ecologically friendly). Each type has good as well as bad qualities, some having more of each than the others.
Whilst during construction it is possible to insulate cavity walls with almost all the above material (though not done generally) after construction or in old buildings only polystyrene beads or glass fibres can be installed only by the special process of "bowing in". The particular polystyrene bead insulation is done if during structure through the inside wall space while it is done from out side surfaces in existing homes. Openings are drilled on the walls right through and checked whether existing insulating material exists and if so in what condition. When the cavity is not filled, insulation beads or fibres are blown in through a hose placed in through the drilled holes. A special glue is blown through along with polystyrene beads which keep the beads fused after curing.
Moisture, air leaks and insulating material
Moisture and, air leaks, though not the key cause has a role in the loss of home heat energy in addition to damaging the insulation, reducing insulation properties of the core fill, damaging the wall material and promoting mould growth. A good vapour barrier therefore should be used even with cavity wall insulation. An aluminium foil vapour barrier applied with a water proof adhesive or a liquid type vapor barrier are good solutions (regional fireplace codes permitting). In addition, an aluminium vapor barrier will act as a radiant heat barrier too enhancing the energy conservation further.