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Installing Water Underfloor Heating - The Complete Guide

Increasingly popular in British homes, underfloor heating adds warmth in hard-to-heat rooms, including bathrooms and kitchens. With minimal maintenance costs and an invisible appearance, it's understandable why heated floors have become so popular. 

Whether you are a professional installer or a handy home DIY’er, here's a guide on how to lay water underfloor heating.

How difficult is it to install underfloor heating?

It is not difficult to install water underfloor heating yourself, provided you are competent at DIY, you have the right tools for the job and give yourself enough time to complete the project. 

With proper planning, you can do the bulk of the installation yourself, including the pre-installation floor prep and pipe layout. Although, you may need to enlist the help of a qualified plumber when it comes to connecting the water system to the mains. Of course, you should only embark on such a project if you are confident that you have the capabilities to see it through. 

What materials will I need to install underfloor heating?

You will need a range of professional tools and materials to install water underfloor heating. These include: 

Our range of underfloor heating kits are popular with homeowners and tradespeople. They make installing a wet underfloor heating system easy and hassle-free by providing all the key components you need in one pack. 

Shop underfloor heating kits 


How to lay water underfloor heating - a step by step guide 

1. Check your design 

This is the most important step of your installation and one that shouldn't be overlooked. Before starting, it’s crucial that you review your schematic design to ensure a simple and easy installation.

Start by checking the drawings to make sure that your manifold has been situated in the correct position. Next, confirm that the underfloor heating pipework is covering all the correct areas. 

Once you are happy that everything is planned correctly, you are ready to start your install. 

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2. Clear the subfloor

Before you start the installation, make sure that the subfloor is clear of debris and is free from any sharp edges or foreign objects that could damage the pipework. Although UFH pipe is strong and durable, you will want to minimise any risk of damage from the outset.  

3. Lay the insulation (for in screed systems only)

It may be necessary to install a damp-proof membrane on the subfloor before the installation layer, especially if you are installing on the first or second floor of your property. 

The insulation layer then sits below the UFH system to minimise heat loss through the layers of the floor. Proper insulation is extremely important as it will boost the efficiency and heat output of your system, as well as reducing running costs. 

4. Install the manifold 

The manifold should be installed first. Decide on an appropriate mounting site based on the weight of the manifold and how many pipes it holds. Ensure that you connect the underfloor heating pipes to the flow side of the manifold. 

Read more about manifolds or choose the right type for you on our Manifolds & Parts page.

5. Connect the pump

Connect the ball valves to your underfloor heating pump first, ensuring they are tightly fixed. Then connect the pump to the manifold and check the fittings are tight to avoid any leaks. 

6. Lay your overlay or fixing system (if applicable) 

If you are using an overlay/board system such as a positioning panel, joist plate, foil overlay or simply retro mesh, then ensure you lay this as per the manufacturer’s instructions before laying the pipework. 

7. Lay the pipework

Lay the pipework by snaking it out from the manifold in the layout specified by your design. Ensure you leave a consistent amount of space between each pipe to allow the heat to be evenly distributed. Staple the pipework into place through the floor level using UFH pipe staples and a staple gun. 

Once you have finished laying the pipe, return it to the manifold and connect the pipe to the bottom return port. 

8. Test the system

Check the system’s pressure is correct and identify any leaks in the manifold, pipework, or joints.

9. Install the edge insulation (in screed systems only)

Edge insulation provides an expansion gap for the screed floor as it heats up and cools down. Run the insulation around the perimeter of the floor, internally and externally, and secure with UFH staples. Make sure to press it into the floor insulation every 1.5m. 

10. Lay the screed (in screed systems)

Lay the screed on top of the pipework, ensuring that you have calculated the correct amount of screed for the heat output required. Ideally, you want between 40W/m2 and 55W/m2 of heat. The thicker the screed, the longer the floor will take to heat. With the correct thickness of screed, your floor should take around an hour to heat up. 

11. Connect to the boiler and thermostat

Now you are ready to connect the manifold to the boiler pump and double-check the system is working correctly. This step may need to be carried out by a qualified plumber. Finally, connect your thermostat and choose your required settings. 

Underfloor heating floor coverings

Now that you know all the steps to install underfloor heating, you may be wondering what type of flooring is best for your project. We’ve compiled a comprehensive guide to the best flooring for underfloor heating that answers all of your flooring related questions here: The Best Flooring For Underfloor Heating

For help with your underfloor heating project, contact our expert team today. We provide free quotes and offer a specialist design service. We even provide a free CAD design with every purchase of an underfloor heating kit

Get in touch today! 

Frequently asked questions

How long does it take to install underfloor heating?

The time it takes to install underfloor heating will vary depending on the size and complexity of the install. It could take a trained professional installer one to two days to install one a room (single zone) system, whereas it could take a competent DIY’er up to a week. A larger home or a commercial installation may take up to five days to complete.

Do you need building regs for underfloor heating?

Building regulations require that there is a significant level of insulation present beneath the underfloor heating system. This limits downward heat loss and increases the efficiency of your system, whilst saving you money on your heating bills. 

Can you lay underfloor heating on top of concrete?

It is possible to successfully lay underfloor heating on top of an existing concrete surface or subfloor. If you've got a polished concrete floor already, then you'll likely be able to fit insulation along with a low-profile underfloor heating system. 

Can you put underfloor heating into an existing house?

Underfloor heating can be successfully installed in new and old homes, including a variety of renovation projects.  Most systems can be retrofitted with your existing subfloors without the need of excavation. 

What is the best base for underfloor heating?

The best base for underfloor heating is a layer of waterproof membrane that covers a clean subfloor. On top of the membrane sits a layer of good quality insulation, followed by your insulation boards. The underfloor heating system is then installed on top and secured with staples that penetrate the insulation boards. 

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