Get the best price on internal wall insulation. From insulated plasterboards to cavity slabs - we have everything you need at trade price.

Internal wall insulation is installed 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/fibreglass slabs and other forms of insulation depending on the method of installation applied.

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100mm Recticel GP Insulation Boards (1200x2400mm)

£36.20 ex VAT

Celotex 100mm PIR Insulation Board – GA4100 (2.4m x 1.2m)

£36.20 ex VAT

Kingspan Kooltherm K118 37.5mm Insulated Plasterboard

£1,325.50 ex VAT

Rockwool RWA45 100mm Acoustic Insulation Slab

£19.61 ex VAT

120mm Celotex Insulation Board – XR4120 (2.4m x 1.2m)

£46.50 ex VAT

25mm Recticel GP Insulation Boards (1200x2400mm)

£14.50 ex VAT

50mm Celotex Insulation Board – GA4050 (2.4m x 1.2m)

£20.69 ex VAT

50mm Recticel GP Insulation Boards (1200x2400mm)

£20.69 ex VAT

70mm Recticel GP Insulation Boards (1200x2400mm)

£29.50 ex VAT

75mm Celotex Insulation Board – GA4075 (2.4m x 1.2m)

£30.96 ex VAT

Rockwool RW3 50mm Acoustic Insulation Slab

£378.00 ex VAT

Rockwool RWA45 50mm Acoustic Insulation Slab

£21.25 ex VAT

Rockwool RWA45 75mm Acoustic Insulation Slab

£22.01 ex VAT

150mm Celotex Insulation Board – XR4150 (2.4m x 1.2m)

£57.25 ex VAT

70mm Celotex Insulation Board – GA4070 (2.4m x 1.2m)

£29.50 ex VAT

80mm Celotex Insulation Board – GA4080 (2.4m x 1.2m)

£34.33 ex VAT

Internal Insulation

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

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 professionals 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 structure of the building.


Cavity wall insulation can be installed within existing buildings by injecting insulation into the walls. This is not always a recommended method.

Cavity wall insulation can be installed into a new building or extension by fixing cavity wall slabs in between the outer leaf and the inner leaf of the wall of the building (in between the blockwork and brickwork) and continuing to fit the insulation as the wall is being built up.

Solid Wall Insulation

Solid walls are solid from the internal brick through to the external side with no cavity.


To insulate a solid wall, a timber frame can be applied to an existing wall and then insulated with insulation rolls, slabs, or boards and then completed with plasterboard. The wall can then be finished with plaster, paint, skirting and coving and so on.

Another method is to install insulated plasterboard directly onto the existing walls.

Partition / Stud Wall Insulation

A partition/stud wall is a wall installed to separate a room either at home making one bedroom into two, or in a workspace making one room into multiple offices.


Install a timber or metal frame to the existing walls and ceilings where needed to separate the rooms. Install insulation into the new stud and cover with plasterboard before applying finishings such as paint, wallpaper, and skirting boards.

Why do I need wall insulation? / Further information:

Wall insulation will prevent heat from 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 travelling 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 building's 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 plasterboard is a high-quality board of rigid polyisocyanurate (PIR) with foil facings bonded to each side that is fixed onto a 12.5mm plasterboard. This achieves a 2in1 product that will save money and time on installation. It can be cut with a knife or a saw and has a thermal conductivity of 0.022W/mK. These boards have a range of different sizes to fit every installation need. Insulated plasterboard is available from brands Celotex, Kingspan, Siniat, Speedline and more.

PIR Insulation Board –

Insulation boards are high-quality boards made up of a rigid polyisocyanurate (PIR) core that has a layer of low emissivity foil bonded to each side. It is lightweight and easy to cut, handle, and install. It is 2400mm by 1200mm and gives a thermal conductivity of 0.022W/mK. PIR Insulation Boards are available from brands Recticel, Ballytherm, Kingspan, Mannok, and more.

Cavity Wall Slabs –

Cavity wall slabs are high-quality resin bonded slabs made up of Polyisocyanurate (PIR) with foil facings. It is lightweight and easy to handle and install. These boards are generally 1200mm by 450mm, designed to fit between wall ties, and give a thermal conductivity of 0.022W/mK. Cavity wall slabs are available from Celotex, Kingspan, Recticel, and more.

Mineral wool/glass fibre –

Mineral wool and fibreglass products are available in non-combustible slabs and rolls. Their flexible materials are designed to shrink and expand with timber frames. They are lightweight and easy to cut, handle, and install with thermal conductivity of between 0.032W/mK and 0.044W/mK. Mineral wool and fibre glass products have a wide range and can be installed in multiple wall applications.