Floor Insulation Boards

What are Floor Insulation Boards?

Did you know that at least 10% of household heat is lost through the floor? Floor insulation boards are a must when creating a complete seal around a building. 

Not only do they do an excellent job of reducing the U Value of your floor in line with current building regulations but they also work behind the scenes to improve the heat retention of a property.

Whether you're looking to insulate solid ground floors, suspended floors, heavy-duty floors or soffits, floor insulation boards are a comprehensive solution to sealing off gaps between floors and skirting boards. 

A property that is sealed off from the elements will maintain a temperature-controlled interior - meaning cooler summers and warmer winters which, luckily for you, goes hand in hand with lower energy bills. 

What's more, floor insulation boards are just as convenient as they are thermally efficient. Rigid yet lightweight in their composition, floor insulation panels can be cut into different shapes with ease.  

Whether you're looking for high compressive strength or precision cut tongue and groove joints, there's a floor insulation board for every job. 

Floor Insulation Board Types

We sell a range of the most popular floor insulation boards available on the market.  

When it comes to insulating floors, our customers tend to lean towards boards as they are easier to handle and install than other popular floor insulants such as insulating screed and polyurethane spray.

When choosing the right insulation board, our customers can choose from a range of materials. Follow this guide to find out which material best suits your insulation needs.

• PIR - Polyisocyanurate (PIR) is equipped with a few simple properties that make it an excellent choice for a range of insulation needs; it has a closed-cell structure (and is water-resistant thanks to this), is extremely lightweight, and also rigid. With a thermal conductivity of just 0.022 W/mK, PIR boards are highly thermally efficient, offering affordability, availability and thermal performance in one robust material.
• Phenolic - Phenolic floor insulation boards are the holy grail of thermal insulation boards. They have over 90% closed-cell formation and deliver unparalleled protection against heat loss with minimal thickness. Offering water-resistance, fire retarded properties and thermal conductivity values as low as 0.018 W/mK, phenolic insulation is the highest performing insulant on the market.
• EPS - Expanded polystyrene (EPS) is the least thermally efficient insulation solution with a thermal conductivity of 0.038 W/mK. Despite its performative inferiority to more premium brands of thermal insulation, EPS exhibits consistent thermal performance in an extensive range of building insulation applications. Not only does it possess high load-bearing capacity but it is also moisture resistant and unaffected by bacteria, moulds and fungi.
• XPS - Extruded polystyrene insulation XPS is manufactured, as the name would suggest, through an extrusion process. Kingspan is the main manufacturer of this insulation in the UK. The closed-cell structure of extruded polystyrene (XPS) prevents water penetration, thus acquitting the need for a vapour control layer. Kingspan GreenGuard boards have a thermal conductivity of 0.034 W/mK. As such, XPS foam is marginally more effective than EPS foam as a thermal insulator.  

We stock Kooltherm K103 Floorboard a premium floor insulation board with a thermal conductivity of just 0.018 W/mK. These Kingspan boards should be used where ultimate thermal protection is required. If it's fire resistance you're after take a look at our Rockwool Insulation page. 

Flooring Applications That Benefit From Floor Insulation Boards

• Underfloor Heating Systems: Floor insulation boards are commonly used in conjunction with underfloor heating systems. They not only minimise heat loss but also help to distribute the heat evenly across the floor surface, optimising the system's efficiency.
• Floating Floors: When installing floating floors, such as laminate or engineered wood, insulation boards can be placed beneath to provide thermal insulation and reduce noise transmission between floors.
• Concrete Floor Insulation: In concrete flooring, insulation boards placed beneath the concrete slab enhance both energy efficiency and structural stability. This method is particularly effective in commercial and industrial settings.
• Suspended Floors: Insulation boards can be used between floor joists in suspended floors. This helps maintain a consistent indoor temperature and prevents heat loss through the floor.
• Loft Conversions: For converting attics or lofts into livable spaces, floor insulation boards are vital. They offer a cost-effective way to insulate the floor, keeping the space comfortable year-round.

Laying Floor Insulation Boards

Installing floor insulation boards does not have to be difficult. Follow these floor insulation board installation tips for your project.

Please note when laying insulation you may need other building materials such as a damp-proof membrane.

● Prepare the floorboards - Clear any debris and dust away. You might have to use a layer of plywood to ensure the floor level is flat.

● Prime solid floor - You need to prime a concrete floor before you lay insulation boards. Thermal primers can help to further reduce the loss of heat from your home. If you are laying insulation under timber floors, you do not have to worry about primer. You can also lay a damp proof membrane below or above the floor.

● Cut the boards - You can cut floor insulation boards with a standard utility knife. We recommend marking your measurements on the board before cutting to avoid mistakes.

● Place the boards - You should stagger insulation boards to reduce drafts. If you are laying solid floor insulation, use an adhesive to secure them in place. For a suspended timber floor, we recommend screwing the boards into place at 300mm intervals across the floor space. It's important not to block air bricks.

● Seal the joints - You need to make sure that the seams between the joints are sealed. Lots of people use waterproof tape to seal the joints. Some people go the extra mile and use acrylic sealant before the tape.

You should always consult a professional for non-standard insulation projects.

Floor Insulation Board Thicknesses

We stock boards that range from 20mm to 150mm. 

If you purchase a thicker insulation board, you can increase the thermal value of the build-up of products. However, due to space restrictions, you may have to opt for a thinner board.