Cavity Wall Insulation Materials

What Are The Various Cavity Wall Insulation Materials That You Will Need?

Cavity wall insulation materials are normally injected into the cavity formed between two parallel walls through holes that are drilled into the outer wall’s mortar joints. In fact, it is a specialist work that is covered by a Cavity Insulation Guarantee Agency (CIGA) and is certified to last at least for 25 years. Sometimes, cavities are examined with the help of a borescope, both before and after the installation to check the quality of the work. A ‘thermal imaging camera’ shows if there are any cold spots that have been left uncovered.

Here are some of the cavity wall insulation materials that are needed to get the job done, and meet your energy saving needs.

1. Beads and granules are often used for insulation within the wall cavities. It may consist of expanded polystyrene (EPS) beads that can be used by using pentane as a blowing agent. These spherical beads are free from CFCs as well as HCFCs and since they are extremely free flowing, there is no need for any injection holes. Also, their tendency to escape through the holes is very limited due to the adhesive coating that is purposely applied. Granules (whether EPS or polyurethane) on the other hand, appear to be less suitable for the job as they are irregular in shape and are less free flowing.
2. Blown mineral wool consisting either of glass wool or rock wool is also used as insulating materials since they are basically inert and inorganic in nature. However, they should be free of CFCs and HCFCs. Manufactured strictly to BS3533:1981 standard, they qualify as having zero ODP (ozone depleting potential) as well as zero GWP (global warming potential). When blown into the cavity, starting from the bottom, they should be checked regularly for even filling and appropriate density.
3. Urea Formaldehyde Foam that consists of a resin and hardener solution is injected into the cavity with the help of compressed air to form a tough insulation material. As the foam dries and hardens inside the cavity, strong formaldehyde vapor is generated. If this vapor enters the dwelling due to poor sealing of the inner wall, it may cause allergic skin reaction or irritation to the eyes or the upper respiratory tract. However, as soon as it diffuses, the problem is resolved and whatever minor traces are left easily goes away in a day or two.
4. Polyurethane Foam or Polyurethane Cavity Foam consists of several liquids that are mixed together to form a foaming substance that is injected into the wall cavity. In due time, it expands and adheres both sections of the walls, forming into first class cavity wall insulation materials. Although the thermal insulation potential of the foam is excellent, but it often cost more and thus the use is somewhat restricted.
5. A rigid board for insulation may also be used to insulate the solid wall from the inside.
6. Some people believe in the use of glass fiber and mineral for insulation because they are carcinogenic. However their results are debated.

Surprisingly enough, many people believe that filling the cavity with insulation material will cause greater moisture problem as dampness from the ‘outer wall’ will find a medium to reach the ‘inner wall’, making it damp in the process. However, this is just a myth. In fact, a government sponsored independent study conducted in the 199o’s found that filling the cavity with insulation does not cause greater dampness as compared to those where the cavity is left unfilled. Actually, the use of cavity wall insulation materials reduces the condensation forming risk on the wall’s inner surface.