TKA have partnered with Envirobead Ltd to provide customers with Envirobead Plus, the latest in bonded bead technology.
Many houses in Ireland have no insulation in the cavity walls. A €400 grant is now available under the Home Energy Savings Scheme towards the cost of cavity wall insulation.
Our SEI ID Number is 10574.
If you don’t have cavity walls, we also do Drylining and External Wall Insulation.
Bonded Bead is made using a specially manufactured grade of closed cell polystyrene FRA thermal bead, which is formed in a pressurised chamber full of temperature controlled steam. The result is beads, which are warm-air dried and then allowed to cure overnight. Repeating this on the following day produces Bonded bead. These steps take place under very strict quality control procedures to ensure the standard of the product is kept.
The polystyrene is blown into the cavity in the form of small beads (similar to what is used in bean bags). The great benefit of this material is that it flows almost as free as liquid and finds its way into the tiniest space in the cavity.
Unlike glass wool it does not need to be compressed inside the cavity to serve its purpose effectively so achieving a specific density of the bead within the wall is not required as is the case with mineral (glass) wool. Walls built before metrication was introduced in 1980, were walls with a 2” cavity unlike today’s metric walls with a 3” (80mm) to 4” (100mm) cavity. Narrow cavities can be more difficult to fill to a required density than narrow cavities so it is very important to use a material which flows easily and gives a consistent density in these circumstances. Another benefit in using a free flowing material is that fewer holes need to be drilled in the wall and this is very appealing to the householder. (See Figure1)
It is impossible to leave gaps in bonded bead insulation but should insufficient material be blown into the wall, the cavity will be totally empty at the top of the wall. If insufficient material is used, the quality of other forms of insulation are much more difficult to ascertain and it is almost impossible for the customer to prove if the density of the material is inadequate when glass wool is used.
This is a very vulnerable position for the householder to be in, and not one that we would advise.
When bonded bead is pumped into a cavity wall, every bead is coated with an air drying adhesive during the injection process. This special bonding agent allows the beads to flow freely until the cavity wall is completely fitted. The adhesive then sets, forming the beads into a bonded homogeneous heat saving mass which will not shrink, crack, settle or be unduly affected by the removal of any of the outer brickwork for alterations or window replacement.
Figure 2 shows how bonded bead fills the cavity
It is generally accepted that bonded beads are the safest form of wall insulation including systems (such as polystyrene board) which are fixed to the inner wall and leave a 40mm empty cavity. All other systems must be installed in the peaks of a house to prevent the risk of moisture crossing the material at the point it would end. i.e. bedroom ceiling level.
Ventilation
A cavity wall has two main functions:
- The most important is to drain away any moisture that may enter from the external wall. Bonded bead does this naturally.
- Also it must allow the wall to breathe and to circulate air.
Bonded beads circular shape allows air to circulate around them, and hence allows air to circulate in the cavity. The beads can only touch one another at one point, therefore when the beads are blown into a cavity wall; there is a ventilation gap between them, which is shown below.
Moisture Drainage
Driving rain causes water to seep through the external wall and to enter the cavity. This water must be drained away naturally and not across the cavity to the inner wall.
Bonded bead does not act as a medium to take water across the cavity.
Because Bonded bead is not porous, it will not absorb water by capillary action. The water that does seep through drains away freely.
Water always takes the easiest route and, because of gravity and the shape of the bead, this is down, not across.