Find the best price on all wall insulation at Trade Insulations. The home of top brands at trade prices. Wall insulation is a popular type of insulation, which is installed externally or internally to the building's walls to improve the thermal conductivity of the residential or commercial building. The materials are frequently made up of high-performance, rigid polyisocyanurate (PIR) featuring foil facings on both sides or mineral wool slabs and other forms of insulation depending on the method of installation applied.

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100mm Knauf Acoustic Roll – 2x 10.3m x 600mm (12.36m2)

£67.69 ex VAT

100mm Recticel GP Insulation Boards (1200x2400mm)

£39.90 ex VAT

12.5mm Gyproc Wallboard Plasterboard (2400mm x 1200mm) – Tapered Edge

£8.79 ex VAT

12.5mm Siniat GTEC Moisture Board – Tapered Edge (2400 x 1200mm)

£13.96 ex VAT

Celotex 100mm PIR Insulation Board – GA4100 (2400mm x 1200mm x 100mm)

£39.90 ex VAT

Celotex 37.5mm Insulated Plasterboard (2400mm X 1200mm X 37.5mm) – PL4025

£39.32 ex VAT

Celotex CW4100 100mm Cavity Wall Board (1200mm x 450mm)

£62.89 ex VAT

Kingspan Kooltherm K118 37.5mm Insulated Plasterboard

£1,458.05 ex VAT

Knauf 100mm Loft Roll 44 – Combi Cut (13.89m2 Roll)

£32.54 ex VAT

Knauf 25mm Acoustic Roll (2x600mm)

£48.63 ex VAT

Knauf Dritherm Standard Cavity Slab 37 100mm (1200mm x 455mm)

£40.25 ex VAT

Knauf Dritherm Ultimate Cavity Slab 32 100mm (1200mm x 455mm)

£39.40 ex VAT

ROCKWOOL Flexi – 1200 x 400 x 100mm – (2.88m2)

£827.74 ex VAT

ROCKWOOL Flexi Slab – 1200 x 600 x 100mm – (4.32m2)

£1,150.00 ex VAT

Rockwool RWA45 100mm Acoustic Insulation Slab

£22.55 ex VAT

100mm Recticel Eurowall Cavity Wall Board (1200mm x 450mm)

£118.13 ex VAT

How is wall insulation installed?

Before installing wall insulation work out what type of wall you have. This includes solid walls – where these is no gap so it can’t be filled with cavity wall insulation and layering methods should be applied, and cavity walls – where the wall is made up of two layers with a small gap in between them that can be filled with insulation.

Methods to check the type of wall for your property:

  • Check the brickwork. If the bricks show the side length and end width (smaller end of the brick) it is more than likely a solid wall. If the bricks are all even and length ways, is it more than likely a cavity wall.
  • If the brickwork has been covered check the windows to measure the depth of the wall. It the wall is more than 260mm thick it is probably a cavity wall. A narrow / thinner wall is probably solid.

Internal Wall Insulation

All wall fitting such as skirting boards, coving, radiators, and so on will need to be removed before the internal insulation takes place. They can then be reapplied after. Ensure extra insulation materials are applied to avoid thermal bridging.

Internal Cavity Wall Insulation

Cavity walls need to be inspected by a professional to find out whether it is a suitable space to insulate. Ensure the professional check for messy brickwork, mortar drips, timber and steel frame constructions, mould or damp in the walls, and walls facing driving rain. Insulation combined with these factors can be damaging to the buildings structure.
Cavity wall insulation can be installed to existing building by injecting insulation into the walls. This is not always a recommended method.
Cavity wall insulation can be installed into a new building by fixing cavity wall slabs in between the outer leaf and the inner leaf of the buildings wall (in between the blockwork and brickwork) and continuing to fit the insulation as the wall is being built up.

Internal Solid Wall Insulation

To insulation a solid wall, a stud wall can be applied to an existing wall and then insulate with insulation rolls, slabs, or board and then covered with plasterboard. The wall can then be finished with plaster, paint, skirting and covering and so on.
Another method is to install insulated plasterboard to the existing walls.

External Insulation

The external wall will need to be inspected by a professional to confirm the walls are not structurally unsound or need repairs.

Insulating the walls externally can be a more practical technique for the property owner as it means no fixtures or fitting on the internal walls such as radiators or décor needs to be affected and less mess is created in your home or workspace.

External wall insulation provides a thermal envelope around the property for a thoroughly insulated household. Details around windows and doors should be provided to ensure heat does not escape through thermal bridging. External wall insulation can be more expensive as once the insulation is installed the building will need to be rendered to cover the insulation and provide protection from weather conditions.


To insulation an external wall a layer of insulation material is fixed to the wall and then covered with render or cladding. A finish can then be applied such as paint, pebble dash, tiles and so on.

Why do I need wall insulation? / Further information:

Wall insulation will prevent heat escaping through the walls. It keeps your property warmer in the winter and cooler in the summer. Wall insulation won’t make your house soundproof however it will add an acoustic advantage and decrease the level of sound traveling through the walls. These components will make your living or working space a more comfortable environment. It also means lower monthly energy bills and making your residential building more energy efficient. Specific wall insulation materials can also be provided for moisture resistance to prevent mould or rot and other insulation materials can increase safety by improving fire resistance.

When installing wall insulation remember to take the buildings fixtures and fitting into consideration as it can increase or decrease the wall depth. This can affect factors such as the space in the room. Also take safety measures to ensure insulation is fitted correctly around electrical sockets, wires and ventilation spaces, or the correct procedures are put into place to remove these components.

Always consult a building professional when insulating your walls to prevent the wrong insulation from being installed and the possibility of damaging your property.

Building Regulations:

Relevant building regulations will need to be met when applying a new layer or replacing an existing layer of wall insulation. Installers will usually arrange this however it is your responsibility to assure you are complying with regulations.

The wall should achieve a U-value of no more than 0.3 W/m2K, if possible. The U-value is calculated by measuring how quickly heat will travel through the wall.


Insulated Plasterboard –

Insulated plaster board is a high-quality board of rigid polyisocyanurate (PIR) that is fixed onto plaster board to achieve a 2in1 product that will save time on installation. It is easy to handle and gives a thermal conductivity of 0.022W/mK.

PIR Insulation Board –

Insulation boards are a high-quality board of rigid polyisocyanurate (PIR) that has a layer of low emissivity foil on each side. It is lightweight and easy to cut, handle, and install. It gives a thermal conductivity of 0.022W/mK.

Cavity Wall Slabs –

Cavity wall slab are high-quality resin bonded slabs. It is lightweight and easy to handle and install. It gives a thermal conductivity of 0.035W/mK.

Mineral wool rolls –

Mineral wool rolls are non-combustible glass mineral wool rolls. They are lightweight and easy to cut, handle, and install with thermal conductivity of either 0.032W/mK, 0.035W/mK, or 0.038W/mK.