Cavity Wall

Reduce the heat loss through your external walls by 30% in an Instant
Cavity Wall Insulation

What is cavity wall insulation (CWI)?

Cavity Wall Insulation (CWI) is an Insulation solution for existing block Cavity Wall built houses where an empty/partially filled Cavity is present. The empty Cavity is filled with expanded polystyrene beads (EPS) which are injected alongside a controlled ratio of a water based adhesive to bind the beads as a solid insulant in your Cavity Wall. The EPS beads are spherical in shape with diameters varying between 2 mm to 8 mm, this ensures free flowing bead movement inside the Cavity for a full fill without any gaps or waste.

Most homes constructed in Ireland since 1930 are built using two layers of block, an inner load bearing wall and an outer leaf of rendered block. The “Cavity” is the gap between the two layers of block, this is how this type of external wall construction got its name “Cavity Wall”. The Cavity typically varies from 50mm to 110mm and may be empty or partially filled with Insulation, depending on the building specification at the time of construction. 

Why Choose CWI?

Cavity Wall Insulation is one of the quickest and cost-effective solutions available to upgrade the Insulation in your home. Installing CWI can reduce your heating bills by 30%, while also gifting you with a warmer and heathier home. As the walls of your home will become instantly warmer, this will reduce any risk of condensation and mold build up, and provide cleaner air in your home.

Installation of CWI is carried out from the outside of your home, with little fuss to the occupants inside. This method produces minimal mess and rainfall will wash away any remaining dust left behind after the Installers clean up. The process is complete in one day, giving you an “Instant EcoHome”.



bonded cavity bead

How is CWI installed?

A series of 22mm holes are drilled on the outside of the dwelling to allow access to the Cavity. The hole locations are determined by a NSAI Agrément certificate pattern to ensure full Cavity fill is achieved.

After drilling, an air compressed injection nozzle is placed into each hole and the EPS beads are injected into the Cavity, along with a uniform layer adhesive.

Injection holes are filled with a colour matched mortar or render. Finally, a qualified Instant EcoHomes auditor will conduct an assessment to ensure the Cavity Wall Insulation meets the required NSAI standard.

Our EPS bead installations are carried using NSAI certified Envirobead Plus EPS bead, which have a thermal conductivity of 0.033 W/m2K.

Cavity wall insulation

Are there grants available to me?

Sustainable Energy Authority of Ireland (SEAI) funded grants are available to all homeowners, including landlords, whose homes were built and occupied before 2011. This is defined as the date your electricity meter was installed.

Grant funding can only be issued once per property for each type of works. This means that any property which previously availed of wall insulation via the Better Energy Homes scheme, or any other government scheme, cannot receive additional support for further wall insulation works

On average, SEAI grants cover 80% of the overall cost of an Insulation upgrade, depending on the size and specification of the dwelling. More details on the grants available can be seen on the adjoining table or search SEAI website for further details.

Instant EcoHomes will complete a free extensive survey report of your home, to ascertain the suitability of CWI for the dwelling. Instant EcoHomes are supplied with Envirobead Insulation products, this allows us to offer excellent Quality Insulation materials, at great value prices to our customers.


SEAI Grant Table

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cavity wall insulation