Insulation Between Floor Joists in the UK: The Complete Guide

Floor insulation between joists improves a home's energy efficiency by installing insulating materials in the spaces between floor joists, typically on suspended timber floors. This technique is particularly beneficial for homeowners with older properties, those living in colder climates, or anyone looking to reduce energy costs and improve indoor comfort. Creating a thermal barrier helps prevent heat loss through the floor, making living spaces warmer and more energy-efficient.

In this article, we'll explore the ins and outs of floor joist insulation, covering everything from what it is and how to install it to its pros and cons and associated costs. We'll also discuss relevant building regulations and help you determine if this insulation method is right for your home. If, after reading our guide, you’re still unsure about what this all means for you, you should consult a specialist who can offer tailored advice. 

Fortunately, with our service, finding a reliable professional and comparing quotes couldn’t be easier. Just fill in our short form, and we’ll connect you with up to 3 local insulation experts. Spare yourself the hassle of endless googling, and click below to get started—it’s quick, simple, and completely free!

Insulating between floors, or floor joist insulation, involves placing insulation between or beneath floor joists to improve a home's energy efficiency and comfort. However, why choose insulation between floor joists?

This method is particularly effective for suspended timber floors, common in older UK homes. Insulation can be installed by lifting floorboards and fitting materials like mineral wool or rigid foam boards between joists. Popular insulation materials include mineral wool, polyester rolls, and rigid foam boards, each offering different advantages in terms of thermal performance, fire safety, and ease of installation.

As mentioned, the best floor insulation can greatly improve aspects of old retrofit UK homes. Here's a step-by-step guide to help you with insulation between floor joists:

By following these steps, you can ensure proper and efficient insulation installation between floor joists, enhancing your space's thermal performance. However, we cannot emphasise enough how important it is to contact an insulation expert for a professionally done installation. 

Using our service, you can save time and effort by contacting multiple installers and contacting them hassle-free. Moreover, we can connect you with up to 3 installers from our trusted network. Click the button below to get started. You’re not obligated to accept any of their quotes; our service is completely cost-free.

Assessing your specific home structure and needs is important when considering insulation between floor joists. While it offers significant energy efficiency and comfort benefits, proper installation and moisture management are crucial to avoid potential drawbacks.

The cost of floor joist insulation in the UK is approximately £4,700, including installation. Homeowners can save up to £100 annually for detached houses and up to £60 for semi-detached homes, reducing 190 kgCO2 emissions per year.

The Great British Insulation Scheme (GBIS) and the Energy Company Obligation (ECO4) are the primary sources of grants for floor insulation in the UK. These government initiatives aim to improve home energy efficiency by funding various insulation measures, including underfloor insulation. 

Some key points about GBIS include:

On the other hand, the ECO4 scheme: 

The GBIS is a UK government initiative that provides a single, targeted insulation upgrade per household to maximise its reach across the country. After a property assessment, the most effective measure to improve energy efficiency is selected, such as floor acoustic insulation.

The ECO4 scheme adopts a comprehensive approach by offering a variety of energy efficiency upgrades for the entire home. This includes insulation and enhancements such as heating system improvements and smart controls, ensuring a more holistic upgrade to residential energy performance.

This approach aligns with the UK government's goal of achieving net-zero carbon emissions by 2050 by making homes more energy-efficient and reducing heating costs nationwide.

Complying with local building regulations is essential when insulating floors. In England and Wales, the regulations require floors to achieve a U-value of 0.25 W/m2K or lower, where possible. This typically involves installing at least 70mm of high-performance foam insulation or 150mm of mineral wool, though requirements may vary based on factors such as floor type or size.

If you need specific information about regulations in your region or clarifications, it's advisable to contact your local Building Control Office or Building Standards Department before commencing any work. This ensures your project meets all necessary standards and avoids potential issues down the line.

Insulation between floor joists is one of the most affordable insulation options in the UK, alongside cavity wall and loft insulation. It provides numerous benefits, such as improved energy efficiency, reduced energy bills, better sound insulation, and moisture control.

It is particularly suitable for retrofitted houses due to its space-saving nature and minimal structural disruption. Homeowners can save up to £100 annually on energy bills, and the insulation helps preserve floor structure by maintaining airflow and preventing timber decay.

Furthermore, grants like the Great British Insulation Scheme can assist homeowners in covering up to 75% of the insulation costs, making this option even more appealing. Has this sparked your interest in floor joist insulation? Fear not, as we can help you get the best deal!  

Don’t waste hours contacting installers on your own. Simply fill out our 30-second form, and we’ll do the rest. We’ll connect you with up to 3 of our trusted installers near you for free, no-obligation quotes. Click below to get started!