Wall Insulation

• A specialist drill cuts 25mm holes at 1m intervals in the outer wall of the house 
• Pump material into the holes
• Once filled, all the holes are blocked off using a matching material

The insulation materials used depend on the space of the area and whether internal or external insulation is required.

To begin with, let’s get familiar with and understand the types of wall insulation:

This type of insulation, often made of fibreglass, mineral wool, or natural fibres, comes in convenient rolls or batts that are sized to fit between the standard spacing of wall studs and ceiling or floor joists. Blanket batts provide a thermal resistance (R-value) ranging from R-3.0 to R-3.9 per inch for standard fibreglass and R-3.8 to R-4.4 for high-performance options, making them a cost-effective and easy-to-install choice for both new construction and retrofitting existing structures.

Spray foam insulation is a versatile insulation material that comes in two main types: open-cell and closed-cell. Each type has distinct properties and uses:

• Open-cell Spray Foam: This type of spray foam has a lower density and a softer, more flexible structure. It is characterised by its open cell structure where the cells are not completely closed, allowing air to fill the open space inside the material. This makes it useful for applications where insulation and air barrier are needed, but not necessarily a vapour barrier. It has a lower R-value, around R-3.8 per inch, but is effective for interior sound dampening.

• Closed-cell Spray Foam: More dense and rigid than its open-cell counterpart, closed-cell spray foam has a higher R-value, approximately R-6.4 per inch, making it one of the most effective insulating materials per inch of thickness. Its closed-cell structure creates a stronger, more moisture-resistant barrier. Although it comes at a higher cost, it provides superior insulation and can add structural strength to walls where applied.

Specifically designed for the voids between the two 'skins' of a double-walled structure, cavity wall insulation involves injecting insulating material, such as polystyrene beads, mineral wool, or polyurethane foam, into the space between the walls. This process enhances the thermal performance of the wall without affecting its thickness or internal appearance. The insulation is typically inserted by drilling small holes in the external wall, injecting the insulating material, and then sealing the holes to maintain the wall's aesthetic.

Blown-in, or loose-fill, insulation is made from fibreglass, cellulose, or mineral (rock or slag) wool in the form of loose fibres or fibre pellets. It is installed by blowing the material into wall cavities, attic spaces, or other hard-to-reach areas with specialized pneumatic equipment. This method is particularly effective for installation in awkward or irregular spaces and has varying R-values: from about R-2.3 per inch for fibreglass to R-3.9 for denser cellulose

Rather than providing conventional R-value insulation, radiant barriers reflect heat away from the living space. They are typically installed in attics in hotter climates to reflect the sun's heat before it can penetrate into the home, helping to reduce cooling costs. Made from reflective materials like aluminium foil, these barriers are usually placed over insulation materials between rafters, joists, and beams to complement the existing insulation.

Wall insulation serves a dual purpose; not only does it play a crucial role in retaining heat during the colder months, but acoustic insulation also contributes to a quieter and more serene home environment. By effectively slowing down the transfer of heat through walls, the insulation ensures that warmth is maintained within living spaces for longer periods. Simultaneously, it helps to dampen external noise, providing both thermal and acoustic comfort.

Heating our homes typically involves using electricity or gas, which, when derived from burning fossil fuels, has a significant environmental impact. Adopting high-quality wall and roof and ceiling insulation can be an effective way to lower energy use in our households, contributing to a reduced carbon footprint.

Adequate wall insulation can considerably cut down on energy usage, resulting in noticeable savings on energy bills each year. This improved efficiency not only reduces your outgoings but also ensures a prompt recovery of your initial investment in the insulation.

Mould is primarily caused by condensation, an issue that can be mitigated with adequate wall and underfloor insulation. This insulation acts as a barrier, preventing moisture from penetrating wall and floor surfaces, which are common sites for mould development. Thus, incorporating such insulation is a crucial step in home maintenance to prevent mould growth.

Wall insulation can often be a quick and non-invasive process, particularly with certain exterior methods. These techniques minimise disruption by focusing on the building's outer walls, leaving the interior untouched. Depending on the scope of the project, the installation can frequently be finished within a single day, typically in just a few hours

The cost of wall insulation can vary significantly based on the chosen insulating material and the installation technique employed. For external wall insulation, the selection of finishing materials for the outer facade also plays a crucial role in the total cost. Options for these cladding and facade finishes include plaster, wood, aluminium, or stone cladding, each contributing to both the aesthetic and the thermal performance of the insulation system.

The following are some of the factors that should be considered before deciding to go for wall insulation:

• Insulation should only be done per the consent of the building, both retrospectively and during the construction process
• All insulation types should adhere to building consent and regulations
• Building compliance guides for insulating pipe ducts and vessels are also available.