How To Install Underfloor Heating on Concrete Floors: An In-Depth Expert Guide

Is underfloor heating suitable for concrete floors? Discover how concrete flooring does not limit the type of heating that you have in your home, especially with underfloor heating added to the mix…

There are many forms of flooring types that you will come across in UK buildings; one of the most popular is concrete flooring, even as the first or final layer of flooring. But did you know that you can still transform your cold, hard concrete floors into a source of warmth and comfort? In this article, you will learn how to install underfloor heating on concrete floors, whereupon you will discover how the efficient and space-saving benefits of underfloor heating can bring greater benefits to your concrete flooring.

Key Points:

How to Install Underfloor Heating on Concrete Floors

Whether you’re updating existing concrete floors or integrating underfloor heating into a new construction, here is the best approach on how to install underfloor heating on concrete floors:

1. Preparing the flooring

To prepare underfloor heating for concrete floors, simply expose the layer of concrete flooring that you wish to lay down the underfloor heating on. 

Once you have done this, clear the flooring of any debris, dirt, or dust to make the area as clean as possible. Most floorboards can be added to concrete flooring once they are dry, flat, and leveled out. 

Other details you need to check over when preparing your flooring are signs of damp, grease, or oil that could cause problems later down the line if you do not adjust these first. Problems like damp and grease can prevent the adhesive from working properly and delay the process.

2. Adding the Perimeter Strip

When installing underfloor heating on concrete floors, ensure that you remove any skirting boards and doors from the area to give you maximum access to the flooring. You will also need to trim them when preparing your final floor finish. Lay down a perimeter strip around the edges of the designated area, and can use sticky tape or a staple gun to keep the adhesive secure. The perimeter strip will allow you to monitor the entire area where you are going to be laying down the underfloor heating as well to help with expansion and reduce heat loss. 

To help aid this process of installing underfloor heating on concrete floors, you can add polystyrene boards to help with insulation and monitor how thick they will be when measuring the room’s height if they are too thick. 

3. Preparing the Installation Area

Before laying down any components, it is crucial to insulate the area thoroughly. Insulation boards are essential for preventing heat from escaping quickly, especially when working with underfloor heating on concrete floors, which are naturally heat conductive. 

Opt for insulation materials like rigid foam, foam spray, or aluminum foil-backed insulation to cover walls, floors, and lofts. 

Proper insulation ensures that the heat remains where it’s needed and improves the system’s overall efficiency. Want to learn more? Discover how to use underfloor heating efficiently.

4. How to Lay Underfloor Heating Insulation Boards

Polystyrene boards are commonly used for their excellent insulation properties and simple installation. 

When installing these boards, consider their thickness to avoid reducing room height significantly. Ensure that the boards are securely fitted and cover the entire floor area to create a uniform layer that will support the heating system.

5. Installing the Heating System with Pipes

For better heat distribution, install the heating pipes or cables directly on top of the insulation boards. It’s important to position these elements closely to avoid cold spots, ensuring a consistent and balanced warmth across the floor. 

For water underfloor heating systems on existing concrete floors, ensure that the pipes are well-aligned and securely attached to avoid any shifts during the screed application.

6. Applying the Screed

The next step involves covering the pipes with a layer of screed, which typically consists of a sand-cement mixture. This layer not only protects the heating elements from physical damage but also aids in heat distribution. 

Semi-dry screed is frequently preferred due to its ideal balance for thermal conductivity and load-bearing capacity. Composed typically of a cement and sand mixture in a 3:1 or 4:1 ratio, this screed type achieves a smooth finish once water is added. 

For a greater performance, concrete with a hardness rating of C35 (35 newtons) and a water to cement ratio below 0.40 is recommended. This specification ensures the concrete is sufficiently robust to handle the thermal demands of underfloor heating systems without compromising structural integrity.

Apply the screed evenly, maintaining a thickness of about 50mm-75mm to optimise thermal conductivity and ensure a level surface for the final flooring.

Here are more helpful tips about screed:

• Best screed for underfloor heating
• How long does screed take to dry

7. Choosing and Applying The Right Floor Finish:

Underfloor heating systems are compatible with various types of floor finishes, from tiles and hardwood to carpet. 

Select a finish that complements your interior design while being conducive to heat transfer. It’s important to choose materials that conduct and withstand heat well, ensuring the efficiency of your heating system.

Try these articles for common flooring types:

• Does underfloor heating work with carpet
• Laminate flooring for underfloor heating
• Vinyl flooring with underfloor heating

What are the pros and cons of concrete flooring? Find out now.

Should You Install Underfloor Heating on Concrete Floors DIY Or With A Professional?

While DIY installations are worth considering for those with experience, it is still better (and safer) to hire a professional heating engineer or consulting with a concrete specialist. 

Professionals can provide insights into the best practices for underfloor heating installations, help prevent common mistakes like uneven heating, and ensure that your installation adheres to building regulations.

Want to get in touch? Find out how to contact us today so that we can assist with your underfloor heating on concrete floor installation

Key Considerations

Whilst these easy to follow instructions paint a bigger picture of what is needed before and during your installation process, there are still some factors to consider to ensure the best results:

Manage Moisture and Cracking

Concrete is prone to cracking if not properly managed. This is why it is important to consider the following measurements: 

• Ensure the room is well-ventilated.
• Consider moisture control techniques during the curing process, (regular misting). 
• Use perimeter joints around the installation area to accommodate expansion and contraction, safeguarding against structural compromises.

Retrofitting

For complex setups, such as retrofitting underfloor heating on existing concrete floors or integrating advanced control systems, hiring experienced professionals can avoid costly errors and ensure a seamless operation.

Heating Systems for Concrete Floors

These are the underfloor heating systems that you can combine with concrete flooring:

• Electric Underfloor Heating Systems: Electric systems, featuring thin heating wires installed just beneath the surface of the floor, are well-suited for renovations with minimal disruptions. These systems heat up and cool down gradually, making them ideal for continuously used spaces. They are relatively simple to install and can be laid directly onto the insulation layer, making them a popular choice for underfloor heating on existing concrete floors.
• Water Underfloor Heating Systems: Alternatively, wet or hydronic systems are perfect for new installations, especially with freshly polished concrete floors. These involve a network of pipes connected to a boiler, circulating heated water throughout the floor for an even distribution of heat. Such systems are generally more efficient for larger areas due to their ability to maintain consistent temperatures across expansive surfaces.

How Much Does Underfloor Heating on Concrete Floors Cost?

The cost of installing underfloor heating varies widely, typically ranging from £500 to £8,000, based on the choice you make with your underfloor heating system, the total area to be heated, and the complexity of the installation. Electric systems tend to be more cost-effective and easier to install, making them a good option for those on a tighter budget or dealing with smaller spaces.

It’s crucial to evaluate the full scope of the project, including any additional renovations needed, to ensure that the heating system fits within your financial plans without compromising on quality or functionality.

Potential Risks to Concrete Floors

While underfloor heating systems offer significant benefits, improper installation can lead to issues with the concrete substrate. 

The main concerns include cracking, shrinking, or expanding if the concrete’s temperature and moisture are not carefully managed. 

Ensuring that the installation complies with all necessary standards and regulations is crucial to mitigate these risks.

Effective Heat To Be Made From Concrete Flooring

By this point, your underfloor heating on concrete floors should be ready to go. Turn on the equipment, and within a matter of minutes, you should begin to notice a difference already from your underfloor heating, after following the instructions laid out before you.

If you have used the right adhesive and followed the pipe layout accordingly, your energy bills should also begin to drop over time too. 

By following these steps, you can install reliable and efficient underfloor heating on concrete floors that will provide warmth and comfort during the cold winter months. With underfloor heating, you can enjoy a warm and cozy home without the need for bulky radiators or noisy fans.

FAQs 

Sources

Lewitin, J., (2024). Concrete Flooring Review: Pros and Cons. The Spruce. [online] Available at: https://www.thespruce.com/in-depth-look-at-concrete-flooring-1314684 [accessed 13/01/2025]