If the gap on your cavity wall is unfilled, most likely you’re just wasting money. Although the walls naturally insulate, it wouldn’t be as much effective without some aid. Truth is, approximately 30-40% of residential heat loss can be attributed to lack in proper insulation. This is why devoting a certain amount of your budget in cavity wall insulation helps regulate the internal home temperature, removes build up of condensation, decreases needless waste of energy, helps conserve our natural resources and most of all, eventually saves you a lot of money on utility bills. The starting expense is not as much compared to the money you will save for long-term. Plus, it can always be installed retroactively since it can be installed through preexisting weepholes or new holes can be bored and sealed over in just a matter of hours.
There are three most commonly materials used in cavity wall insulation: mineral wool, formaldehyde foam, and expanded polystyrene beads. Each of these have its own slight differences and relative advantages and disadvantages that you should evaluate on a case to case basis.
All of the three types have identical characteristics in general. Most homeowners give primary importance for the R value or the insulating performance when deciding at the different options of materials to use. In the case of cavity wall insulation, however, you must first of all consider water retention and fire resistance as well as the quality of air indoors for your home. This is the reason why these three materials are used more often in concurrence with cavity walls.
Mineral wool or Rockwool
This is the material which is used commonly for insulation in residential properties. It is produced from an igneous rock which is heated and spun to create fiber material. This is blown into the cavity wall which then occupies the space between the interior and exterior walls of the building entirely. The material also is water resistant and prevents moisture driven by rain which usually gets though the outer leaf of the wall to reach the inside leaf of the building.
Expanded Polystyrene Beads or EPS beads are utilized in the of cavity walls. These are pushed into the cavity of the walls, which is mixed with an adhesive which sticks the beads together to avoid being spilled outside of the wall. This type of insulation is usually used in narrower cavity walls rather than using mineral wool insulation and is also preferred in some stone built houses or properties.
Cavity Foam Insulation
Urea formaldehyde foam was commonly used for the insulation of cavity walls. They usually have the benefit of needing smaller hole sizes to be drilled in the brickwork or the walls. However, not many people use this nowadays. Most people prefer Polyurethane foam as both a cavity insulation material and a material to stabilize the wall structure where the wall ties have been futile, as an option to replacing the wall tie itself. However, where work is done purely for thermal insulation purposes only, either mineral wool or polystyrene beads are the ones normally used.
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