Underfloor insulation is insulation materials that are installed beneath the floorboards to improve the thermal quality of the residential or commercial building. The materials are available in several products including high-performance, rigid polyisocyanurate (PIR) featuring foil facings on both sides or mineral wool slabs and others depending on the application method. At Trade Insulations, we provide the nation with the best underfloor insulation brands at trade prices.

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100mm Recticel GP Insulation Boards (1200x2400mm)

£39.90 ex VAT

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

£39.90 ex VAT

120mm Celotex Insulation Board – XR4120 (2400mm x 1200mm x 120mm)

£51.25 ex VAT

25mm Recticel GP Insulation Boards (1200x2400mm)

£16.00 ex VAT

50mm Celotex Insulation Board – GA4050 (2400mm x 1200mm x 50mm)

£22.69 ex VAT

50mm Recticel GP Insulation Boards (1200x2400mm)

£22.69 ex VAT

70mm Recticel GP Insulation Boards (1200x2400mm)

£33.19 ex VAT

75mm Celotex Insulation Board – GA4075 (2400mm X 1200mm X 75mm)

£33.90 ex VAT

Kingspan Kooltherm K103 100mm Insulation Floorboard (2400mm x 1200mm)

£319.44 ex VAT

Kingspan Thermafloor Insulation Board TF70 – 100mm – 2400x1200mm

£56.75 ex VAT

Kingspan Thermapitch TP10 25mm PIR Insulation Board

£24.09 ex VAT

Kingspan Thermapitch TP10 75mm PIR Insulation Board

£46.43 ex VAT

Knauf Rocksilk RS45 Slab – 100mm (1200 x 600mm)

£473.98 ex VAT

150mm Celotex Insulation Board – XR4150 (2400mm x 1200mm x 150mm)

£62.50 ex VAT

70mm Celotex Insulation Board – GA4070 (2400mm x 1200mm x 70mm)

£33.19 ex VAT

80mm Celotex Insulation Board – GA4080 (2400mm X 1200mm X 80mm)

£38.62 ex VAT

How is underfloor insulation installed?

There are multiple application methods that can be applied when insulating your floor depending on the type of insulation you need, size, and where abouts in the floor structure in which it will be fitted. Floor insulation can be applied in suspended floors, solid floors, and concrete floors.
Suspended floors
Underfloor insulation can be applied in suspended floors by going underneath the floors into a basement space and fitting insulation into the joists and securing using netting material.
A suspended floor is when there is a space beneath the floorboards and that the floorboards are laying over joists.
If there is no basement the floorboards should be lifted, and insulation fitted into the joists. It can also be applied by fitting netting in between the joists first and then placing the insulation on top of the nets.
Solid floors
Solid floors can be insulated by laying the insulation on top of existing flooring and then covering the insulation with the chosen floor finish. A damp-proof membrane is advised to be laid in between the solid floor and insulation boards to avoid moisture.
This method is not always recommended as it can affect the rest of the properties fixtures and fittings such as raising skirting boards, raising electrical sockets, shaving the bottom of doors and that’s before clearing out the whole space and pulling up the floorboards.
There are several insulation manufacturers that provide underfloor insulation such as Kingspan, Celotex, Iko Enertherm, and others

Why do I need underfloor insulation?

Insulating a floor will avoid heat flowing through the floor where 15% of heat can be lost from a property, this will save money on monthly energy bills. It will also make the property more energy-efficient and reduce the carbon footprint which will help to support prevent climate change.
Always consult a building professional when insulating your floors to prevent the wrong insulation from being installed and the possibility of damaging your property.
Building Regulations:
In England or Wales, the floor should achieve a U-value of 0.25 W/m2K or less, if possible. The U-value is calculated by measuring how quickly heat will travel through the floor. To achieve this standard, at least 70mm of high-performance foam insulation should be used or 150mm of mineral wool roll however this can differ depending on the size and type of floor in the property.

Underfloor PIR boards
Insulation boards are manufactured from rigid polyisocyanurate (PIR), a lightweight foam board sandwiched between two foil facings. It is a lightweight product to ensure easy cutting, handling, and application. It provides a multi-purpose use including, walls, roofs, and floors. It is a much-liked product when insulating floors.
Insulation slabs
Slabs are a flexible material that provides multi-purpose use. They are easy to cut, install and handle making them easily fit within joists and timber frames. This is a common choice when insulating concrete floors. Insulation slabs are available from brands including Kingspan, Knauf, and Rockwool.