The best ways to insulate your floor

19 November 2019

Are you paying too much for your heating bills? Is your house cold and draughty?

Have you already installed some form of insulation, but it just hasn’t made your cold home warmer?

Insulating your floor is the logical next step. Suspended timber floors let in cold, damp air, and dust from the void below. This creates cold draughts, uneven temperatures, condensation and mould.

By warming cold surfaces, floor insulation is the cosiest and best way to stay warm in winter, and comfortable all year round.

So, leave the hot water bottles and onesies behind and make the long-term investment in warming your home!

Heat loss through floor boards

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What kinds of flooring are there and what type of floor can you insulate?

The most common type of flooring in the UK is a suspended timber floor, usually found in older homes. A suspended timber floor leaves a crawl space, or void, underneath your floor boards for draughts to pass through. An air vent on the outer wall of the void keeps the crawl space ventilated to reduce the risk of low-level damp, but also often causes draughts and cold air to come through the floorboards, and affect the comfort in the home.

Solid concrete floors are found in most modern properties. Solid floors are generally warmer than suspended floors and cannot be insulated from underneath. Any insulation, if needed, will have to go on top of the concrete slab.


Why do so few property owners insulate their floor?

In the UK, only 3% of suspended floors have been insulated, even though uninsulated timber floors contribute to as much as a quarter of the total heat loss for a typical home! 

Historically, traditional methods of floor insulation have been disruptive and extremely costly, meaning that people haven’t had a simple, hassle free, cost effective solution – until now.


Use a robot to spray underfloor insulation

Q-Bot’s solution involves a robotic device that spray-applies insulation without you having to leave your home, and is one of the cheapest measures to increase your Energy Performance Certificate (EPC) rating for your property. The installation process takes only one to two days for most UK properties and is immediately effective, reducing draughts, improving thermal comfort, and even reducing sound when you walk across your floor.

The insulation process is simple. First, the robot enters the void through a small access hatch in the floorboards. The robot travels through the void, scanning and creating a 3D image of the under floor to ensure the property is suitable. Next, the robot sprays insulation foam to the underside of the floorboards. The insulation expands and fits the shape of the floor, ensuring no gaps are left. The insulation forms a layer under your floorboards, allowing for a ventilation gap between the insulation and the ground beneath to protect from damp and mould. Finally, the installation is scanned and checked to verify that the work has been completed successfully. 

Find out if your house is eligible

If we didn’t use one of our innovative robots to install your underfloor insulation, here is what you would have to do: 


Fit insulation panels under your floor by hand 

Fitting insulation panels by hand can take between one to two weeks. It requires the rooms in your property to be emptied the floorboards to be lifted, insulation panels and an airtight membrane to be cut to shape and installed, and then everything to be put back together and redecorated. This option is very labour intensive, expensive and disruptive.

Poor installation can also lead to gaps between panels creating potential thermal bridges, and areas where draughts and moisture can still penetrate the floor. Poor installation can also overly-compress the insulation, reducing its performance, or allow it to sag, creating pockets of unwanted air between the insulation and the floor boards. Achieving good quality is key but is time consuming and takes skilled labour and oversight to ensure it is done correctly. 


Fill the void or crawl space under your floor with insulation

Instead of meticulously fitting insulation panels, you could just fill the void with insulation. This option is not recommended as it blocks the vents, preventing the flow of ventilation under the floor, causing moisture to build up, and potentially causing more serious, long-term problems with damp and mould. In extreme cases, this can result in deterioration of the joists and any covering above, giving you much bigger problems to deal with! Not only is it difficult to access the void to install the insulation, but this method also requires a lot of material, which increases the cost and time of installation.


Install underfloor heating to warm your floor

For a big improvement in comfort, you can install underfloor heating. Underfloor heating works by using electrical heating elements or hot water to distribute heat over the floor surface. However, underfloor heating also requires underfloor insulation. Otherwise, the energy used in heating the floor ends up heating the void unnecessarily, resulting in poor performance and higher energy costs.

If you are considering fitting underfloor heating you need to consider installation and remember the additional running costs.


Cover your floorboards for improved comfort

One common method of reducing draughts from the floor is to cover it up. You can do this by installing carpet with underlay, a thin layer of cushioning that provides some reduction in sound, moisture and draughts entering the home. Another option is to install vinyl flooring, a plastic material in the form of vinyl floor tiles, vinyl planks or vinyl sheets. It’s easy to install, durable and can be combined with carpet and underlay. However, covering your floorboards can be disruptive and costly, as it involves removing furniture, fittings, and requires redecoration. For example, skirting boards, fitted cupboards and radiators may have to be moved, and the bottom of your doors may have to be cut back. On top of that, it is shown to have limited impact on draughts and thermal losses.


Replace your suspended timber floor with a solid concrete one

This is the most extreme, disruptive and expensive solution. You can get rid of your suspended timber floor and replace it altogether with a solid aggregate and concrete floor like those in modern houses. We would only recommend this solution for homes that have very low voids of less than 150mm deep, or if you have to replace an existing floor because of age, or damage. Once you had removed all of the existing floor and joists, removed any barriers a damp proof membrane (DPM), typically a polyethylene sheet, is laid on the levelled ground beneath. Next you would add a layer of insulation, before pouring the concrete. This approach prevents the risk of moisture rising through the floor. This option can reduce your energy bills in the long-run, but it is expensive and extremely disruptive to install.


If you want to find the best way to insulate your floor, why not complete our checker and see what would work in your home.


Check my house's eligibility 


If you would like to find out more about underfloor insulation, check out our FAQs


Latest environmental concerns, government legislation including the target to bring all UK greenhouse gas emissions to net-zero by 2050, together with homeowners' expectations of thermal comfort and energy savings are all significant drivers to insulate your floor. 


If you are renting a property, following recent legislation, your landlord also has obligations to take energy efficiency measures that can help you save energy and feel more comfortable.


If you don’t already have some form of insulation installed, and want to review all the insulation options for your home, have a read of our Best Ways to Insulate Your Home article.


Learn more about floor insulation and energy efficiency:

Floor insulation, by the Energy Saving Trust.

Funding for energy efficiency, by Simple energy advice. 

Energy Performance Certificates (EPC), by the Energy Saving Trust

What is thermal bridging? by the Greenag