Underfloor Heating: What is it, How it Works & the Different Types

Laying of floor screed

Here at Screed It, we understand that you’ll want to make the best, most informed decision possible before carrying out any work on a flooring project. This is why we’ve brought together this specialist information on the types of underfloor heating, how they work, and what should be done to keep them running once they’ve been installed.

What is Underfloor Heating?

Underfloor heating (sometimes abbreviated to UFH) is a method of heating any interior space by generating and distributing heat underneath the floors of the property. It can be used as a secondary heating system, or it can even become the primary system and replace traditional radiators as the main heat source of a property.

Types of Underfloor Heating

There are two types of underfloor heating available for work projects and renovations, electric or “dry” underfloor heating systems and hot water or “wet” underfloor heating systems. Which type of system you choose will be your decision, though you may wish to consider factors such as running costs, any deadlines you have for installations or renovation work, and how much space you have available for your system in the room where it should be installed.

To give an example, if you are looking to complete the floor of a new build you may want to look at having a wet underfloor heating system installed, as these are designed to heat larger spaces and are generally more cost-effective than electric systems. However, if you need a smaller space covered or need to renovate a property that has already been built, then electric underfloor heating is the better fit and will also be less disruptive to install.

What Temperature Does Underfloor Heating Run At?

The running temperature of underfloor heating will vary, depending on the needs and wishes of the property owner. However, BS EN 1264-2[1] limits the maximum floor surface temperature to 29°C, or to 27°C where floor tiling is proposed. In most living areas, it is suggested that 21°C will keep the temperature in the room comfortable, while bedrooms are set slightly lower (usually around 18°C).

The water that flows through a wet underfloor heating system’s pipes will vary between 35°C and 60°C, depending on heat loss from the building. The temperature you set the system at may vary between these, depending on the type of flooring you have installed above the pipes or wire layout.

Turning the temperature down by a single degree on your underfloor heating system could also help to keep it energy-efficient, while never compromising on the comfort of the room’s occupants.

How Does Underfloor Heating Work?

Underfloor heating system in building

Once you’ve decided to install underfloor heating as part of your work project, the next step should be to make sure you know how it works. This helps you to make the most informed decision for your work and ensures the system you’re using is the most efficient one for your property’s needs.

A typical S-plan underfloor heating system works by evenly distributing heat throughout the flooring of a property. Often, a material such as screed will be laid over it to seal any potential air pockets, which keeps the heat distribution even and makes the system more efficient. The temperature is then monitored by a thermostat to make sure it is kept at a consistent level.

How the heat is distributed will all depend on which type of underfloor heating you have:

Electric Underfloor Heating

An electric system makes use of an ultra-thin wire that is then installed underneath the floor level. The wire is then heated, and the heat transfers outwards.

Wet Underfloor Heating

Wet underfloor heating systems are made up of a complicated pipe layout that can come in a number of different designs. These designs are created to ensure the most efficient and even transfer of heat in a room, though some designs may achieve this more effectively than others. Hot or warm water is then pumped through these pipes, which will also become hot and transmit the heat to the room through the rest of the floor.

You can use any central heating source in a property to provide hot water for a wet underfloor heating system. These include:

  • Biomass boilers
  • Combination boilers
  • Condensing boilers
  • Heat pumps
  • Standard boilers
  • Stoves

What Type of Flooring is Best for Underfloor Heating?

The best type of flooring for underfloor heating is one that makes the most of the potential heat transfer. Hard surfaces such as screed, stone, engineered wood, or ceramic tiles are the most thermally conductive and would therefore offer the best heat transfer. However, there are a number of other options you might want for your property that will also work.

Other flooring options that you may want to consider for your property once underfloor heating has been installed include:

  • Carpets
  • Linoleum
  • Resin
  • Vinyl

Caring for Your Underfloor Heating System

floor screed stoke on trent

Once an underfloor heating system has been installed you should keep in mind how it will need to be maintained. This differs depending on which type of underfloor heating you have installed under your property. Hot water underfloor heating systems, for instance, will need to be regularly flushed out because sludge and rust can build up inside them over time.

To do this, you’ll first need a pump that’s suitable for your boiler. This needs to be fitted to your system so that it sends a flush of chemicals through the pipework and clears out any corrosion, sludge debris or rust. This should keep the system in its full working order.

Electric underfloor heating systems, on the other hand, should not need frequent servicing. However, we do suggest having them checked over by a specialist engineer so that you know your system is working to its utmost efficiency and is not in need of any repair work.

Contacting a Specialist Underfloor Heating Contractor

If you have been considering screed flooring for a planned work project and you believe the finished result would also benefit from an underfloor heating system being installed, contact our team at Screed It today. We’ll be ready to provide the wet system that suits all your needs, and can have it installed exactly as you need it underneath the floor coverings required by the terms of your project. We’ll also be happy to carry this out anywhere in the UK, so you may rest assured that you’ll never be out of reach of our service.

One of our staff members will be waiting to discuss your options when you get in touch with us. They will be able to help you make the best decision for your flooring, so you can feel confident in placing an order and arranging a date for installation.


Our Advice on Underfloor Heating and Screed

Underfloor heating system

At Screed It, we understand the need to keep any work scheduled for a project as quick, efficient, and cost-effective as possible. That is why we’ve provided some professional advice on underfloor heating and screed, how the two should be installed together (including minimum and maximum levels of screed thickness), and what you can do to ensure best practice when carrying out the work.

What is Underfloor Heating?

Underfloor heating (UFH) is a method of heating any interior space by generating heat underneath the floors of the property. It can be used simply to warm up the floor or it may even replace radiator systems entirely and become the primary source of heat indoors. 

When you install underfloor heating, you will normally have the option of two system types. These are electrical systems and water systems. An electrical underfloor heating system will use cables to generate heat, while water-based underfloor heating systems will pump heated water through a series of pipes underneath your top floor layer. 

Installing UFH Systems Underneath Screed

Starting from the bottom, a subfloor will consist of either a concrete slab or a beam and block which is then insulated by a waterproof membrane. This membrane should then be covered with a layer of thermal insulation. In most cases, this will either be polystyrene or mineral wool. There may also be occasions where it will be necessary to fit vapour insulation over the original thermal insulation layer. 

After this, the underfloor heating pipes can be fitted. These should be laid on the floor evenly, avoiding sharp bends if possible (as water-based pipes will need to maintain a free flow), and set out in a loop to ensure an even distribution of heat. The pipes should be fitted to the underlay with clips.

Once everything is in place and prepared, it will then be possible to install the screed mix that’s been chosen for the floor. This will then be left to dry, and a flooring of the homeowner or contractor’s choice can be laid to cover it over. Some may also choose to leave the screed exposed, as a stylish floor finish.

What is the Best Screed for Underfloor Heating?

There are two types of screed that can be installed around underfloor heating. Neither can be considered “best” for an underfloor heating installation, as they offer the same advantages when installed correctly. However, when considering an installation, you should always take into account the type of screed being used in order to allow room for thermal movement and expansion in the pipes.

We have provided some more information on the two types of floor screed mix below:

Traditional Floor Screed

floor screeding leicester

Traditional sand and cement screeds, also called “dry screeds”, are a mix of coarse sand and cement. The ratio of sand to cement may vary depending on the contractor, but the average is normally noted as a 4:1 ratio mix. It also needs enough water to reach the required consistency without getting so wet that it will produce more than a few drops of moisture when squeezed.

Drying times for traditional types of screed will normally range between five and seven days. 

A traditional floor screed will need a minimum of 28 days before the heating can be switched on, and the UFH system should be run at a low temperature at first to let the screed heat up. This assists in completing the cure before the heating is brought up to its full running temperature.

Liquid Screed

Also known as “flowing screeds”, liquid screeds are often considered a faster, more efficient alternative to traditional sand and cement screeds. This is because liquid screed can be supplied to a building project and simply poured into the space it needs to be installed. From there, the compound mix will harden by itself and form a smooth, flat surface. This is why they are often called self-levelling screeds as well.

If you are looking to finish a work project quickly, liquid screed is often the best choice. It can often be walked on within 24 to 48 hours of being installed, though it will take longer to cure than traditional screed. 

Underfloor Heating and Screed Depth

It is especially important to keep to the recommended thickness of a screed layer, as the depth of the pipe determines how effectively the UFH system will distribute its heat. The thickness of the layer also varies, depending on whether you are using traditional sand and cement screed or liquid screed. 

Ideally, a traditional sand and cement screed will have a minimum thickness of 65mm and a maximum thickness of 75mm. No matter the measurement chosen, this should be consistent throughout the work to keep the heat distribution the same.

As liquid floor screed can be installed in thinner layers than traditional screed, the minimum depth of the layer can be as little as 50mm or 55mm. 

Preventing Issues with Underfloor Heating and Screed

When installing underfloor heating and covering it with a screed layer, there are a few other points to follow to ensure best practice:

  • You should ensure that the process takes installations that penetrate floors into account
  • You should always be aware of the maximum temperature of the floor surface, particularly if you are planning to install tiles above the screed
  • Insulating the primary pipework and the manifold assemblies is highly recommended
  • You should also be sure to locate the manifold assemblies so that they are easily accessed
  • The correct labelling should be applied to all features in a UFH system, in order to keep inspections and maintenance efficient
  • Joints between the manifold and pipework should be accommodated above the level of screed for easy maintenance
  • Manifolds should be located at an appropriate height above the floor, securely fastened to the wall
  • All external doors and windows should be installed before any UFH system, so that the property is watertight and the system is protected from frost
  • The spacing and layout of the pipework should be even, but may be reduced around the external perimeter of rooms to compensate for additional heat loss that often occurs in these areas. Insulation will need to be installed from the floor to the edge of the walls

Underfloor heating pipes can be laid out in several patterns. The most appropriate layout for any particular system should be confirmed by the manufacturer.

If you don’t have the necessary experience to install underfloor heating with a screed layer to finish, we would strongly recommend calling a specialist service to undertake the work for you. This ensures that the work is handled correctly and will save you time and money that might otherwise be spent ripping up the screed floor and uninstalling the system if it goes wrong.

Contacting a Professional Screeding Service

If you are in need of fast and efficient screeding and underfloor heating services to complete your work project, contact Screed It today. We’ll do everything we can to provide you with the wet UFH system that keeps any property at its most comfortable temperature, and can ensure an installation is carried out exactly as you need. We will then finish the flooring with a layer of screed that suits the needs of your planned work.

We’ll be happy to carry out this work anywhere in the UK, and one of our members of staff will be ready and waiting to discuss everything you need as soon as you get in touch.


An Expert Guide to Your Underfloor Heating System

Underfloor heating system in building

A popular feature for a property’s floor in the modern day is the underfloor heating system. At Screed It, specialise in providing building projects with underfloor heating, alongside traditional and liquid forms of screed.

We’ve also put together this professional guide on underfloor heating so that you can be fully informed before you decide if you’d like this feature for your property.

What is an Underfloor Heating System?

Underfloor heating is a modern system of central heating and cooling, using either electricity through a series of thin wires or hot water in pipes to evenly distribute heat through a property’s floor.

In many cases, the pipes and wires used in underfloor heating will be set out in what is known as “S-plan”, as this shape of system is familiar to both plumbers and electricians.

How Underfloor Heating Systems Work

When you’re considering installing a new feature in a property, you will naturally want to know how it works first, so that you can then decide if the feature is suitable for your project and intentions. An S-plan underfloor heating system works by evenly distributing heat throughout your flooring, often taking advantage of the lack of air pockets in flooring material such as screed in order to ensure this is achieved. The heat level is then monitored by a thermostat in order to maintain a consistent temperature.

How systems work to distribute heat will all depend on whether your underfloor heating is wet or electric:

Wet Underfloor Heating Systems

Systems that use hot water to transfer heat into a room will allow this water to flow through a circuit of pipes underneath the finished floor design. The pipe layouts will then become hot, allowing for the heat to be transmitted to the room through the rest of the floor.

Any central heating source may be used for wet underfloor heating, including:

  • Standard boilers
  • Combination boilers
  • Condensing boilers
  • Biomass boilers
  • Heat pumps
  • Stoves

Electric Underfloor Heating Systems

Electric underfloor heating systems have an ultra-thin wire that will be installed underneath your flooring. This thin wire then heats up, serving the same purpose as the underfloor heating pipe for a hot water heating design.

The Benefits of Having an Underfloor Heating System

Underfloor heating system

For many homeowners, no one will have explained all the benefits of having an underfloor heating system installed underneath their floor finish. There are many advantages to having this type of system installed for your property, which we have listed here:

  • They allow for increased energy efficiency, by regulating temperature and ensuring that homeowners can turn down the thermostat on their central heating
  • Their energy-efficient nature means that more money is saved from energy bills
  • They will still be fully efficient underneath any floor layer added on top, whether you choose to put down tiles, carpet or timber flooring
  • Water varieties will only need a minimal amount of maintenance, in the form of a regular flush and pressure testing
  • Underfloor heating minimises the amount of dust circulated in a property, making them more comfortable for those with allergies or asthma
  • S-plan systems in particular can make a property feel more comfortable in terms of temperature, as the heat is evenly distributed across the whole floor
  • Damp and dust are eliminated, making them more hygienic
  • They free up space by removing the need for radiator systems

How to Flush an Underfloor Heating System

Owing to how it works, you will need to regularly flush out any underfloor heating system that uses water. Like central heating systems, these pipes may have sludge and rust build up inside them over a long period of time and will need to be cleaned out in order to be kept in their best working condition. When this happens, you will have to power flush your system.

The process involves fitting a pump (the type that is best suited to your boiler) to your system, before sending cleaning chemicals through your pipes. This should clear them of any corrosion, sludge debris or rust that may have been preventing the system from working properly.

We do recommend that this work is carried out by an experienced professional, in order to ensure that the flush is performed correctly and safely.

Underfloor Heating Costs

The costs involved when you have an underfloor heating system can vary greatly, especially when the installation and overall running costs are also taken into account. Depending on the size of the area you have fitted your pipes or thin electrical wires, as well as daily and seasonal usage, the price you pay for your underfloor heating may fluctuate over time.

This difference will be especially prominent during summer and winter months, as the running costs will be lower in the months where you can safely turn the system off without feeling too cold in your home.

Contact Us for the Best Heating System for Your Property

An underfloor heating system under construction

If you have been looking at screed flooring for your property and you believe that your work project would benefit from a hot water-based underfloor heating system as well, get in touch with Screed It today. We’ll do everything we can to ensure that your wet system is delivered and installed exactly as you need it, underneath your planned floor coverings. We can do this anywhere in the UK, so there is no need to hesitate when you need a heating system with a wet design.

One of our staff will be happy to discuss the best options for setting out your system as soon as you get in touch.


Can Underfloor Heating be Left on All the Time?

As we are often subject to very cold winters here in the UK, it is advisable to leave underfloor heating on all the time during the colder months. However, the temperature it should be left on will depend on individual circumstances, including how often the heating system is used and how much activity there is taking place in the building. 

Underfloor heating may also take several hours to warm up, so turning it down to a reduced heat rather than turning it off is considered best for your property. This will ensure that any interior is warmed up at a faster rate when temperatures drop. You shouldn’t need to do this during warmer months of the year.

Can You Put Furniture on Underfloor Heating?

While it is possible to put furniture on top of hot water-based underfloor heating, flat-bottomed furniture must not be placed on top of electric UFH systems. This is because they risk covering the heating mat or cable, which can restrict airflow to the floor. In turn, this may lead to thermal blocking or even to the cable overheating, which can become a fire hazard.

Will Underfloor Heating Raise my Floor?

Because both wet and electric underfloor heating systems are installed directly beneath floor finishes, it may impact on the height of the floor once the work is done. However, this will be unnoticeable, as the system can be fitted with a layer of tile adhesive, or even placed in the subfloor itself.


How to Screed a Floor

how to screed a floor

A common project to carry out on floors for work or home projects is to install a screed layer. This can be extremely difficult to do without prior experience and the correct tools to carry out the work, so it is important to have all the training and equipment necessary if you want to do the job yourself. A floor which is poorly screeded can easily become damaged later on, even to the point of breaking up and forcing you to begin laborious, expensive work again, so it is important to be well prepared before even beginning to prepare a floor for screeding.

Here at ScreedIt, we have many years of experience in installing high quality, durable screed floors for customers across the UK. As such, we know how to screed a floor step by step, and we can demonstrate this to our customers quickly and professionally. If you have been looking to screed a garage floor, kitchen floor or even the floor of a larger complex such as a warehouse building, we will be able to install it just as you need.

Get in touch with us today and we will be able to screed your planned floor to your exact specifications, using the latest tools and equipment to ensure that the project is completed to the highest standards.

How to Prepare a Floor for Screeding

Depending on the type of screed used and the size of your intended site, a number of factors about your installation can change. This can include the time it will take for your screed to finish curing, the thickness the screed will need to be poured at and how much it will cost overall to screed your floor. 

Because of this, it is important to have a plan in place before your work begins. Be sure to have measured the area you are intending to screed, in order to start the project. You will also need to reinforce the layer your screed will sit on if you are intending to use unbonded screed, or expose the aggregate and apply a bonding agent if your screed is bonded. The layer should also be cleaned of all dust and debris before work continues, and the site must be proven to be watertight.

You may also need to mix the screed for a concrete floor, if you are intending to use unbonded screed. By adding polypropylene fibres into the mix and adding water, you will reduce the chances of your floor developing micro cracks over time.

When you choose to use ScreedIt to carry out your installation, you will not have to worry about how to prepare a floor for screeding, or how to mix screed for a concrete floor, as we can discuss what your project will require before beginning any work. Contact us today to learn what we can do for your project, including what we will plan for, pre-installation.

How to Screed a Floor, Step by Step

how to screed a floor

There is a several step process to installing a screed floor, which we have listed below:

1. Divide up Your Floor Area

To begin the process of screeding your floor, you will need to divide it into sections. At ScreedIt, we will provide our own dividers, but if you do not have these, it is recommended that you use long, straight pieces of timber that are cut to the height of the layer. Wet these pieces down so that they are easily removed after and divide the room into strips.

2. Apply a Layer of Screed

Spread out a compact layer of the screed mix on the section farthest from the room’s entrance, using a trowel to move the mixture and compacting it with a screed board or straightedge. Tamp the edges with a tamper to help complete the section.

This part of the process often results in one of the most common problems, which is poor compaction. To ensure that your floor is installed smoothly and correctly, you may wish to call a professional service instead. Call us and we will be able to send our dedicated, highly trained team to screed your floor to the standards needed.

3. Levelling a Floor With Screed

If your screed is not self-levelling (sand and cement screed), you will need to use a straightedge or a straight piece of timber to level the floor. Place it over the timber pieces you are using to divide the sections and push it forward, tilting it to use the corner as a cutting edge and moving it side-to-side in a sawing motion. This will level the screed layer.

If your screed is self-levelling (otherwise known as flowing screed, or liquid screed), it will already have an agent mixed in that will react when the screed is poured, causing it to compact by itself. This ensures that the level will already be smooth when the screed is completely cured.

To learn more about how to screed a floor with self-levelling screed, get in touch with us today. As a professional screed installation contractor, we have screeded many floors with self-levelling mixtures, so we will be able to answer any questions you may have.

4. Repeat the Process

Continue to screed your entire floor until you have filled all the sections available. Once this is done, remove the timber dividers and fill in the gaps left behind. Repeat this process until your entire floor has been screeded.

5. Float Your Screed

You will be able to remove some imperfections from the new screed floor layer as soon as it has been installed, and once again after the concrete has properly bled.

6. Cure Your Screed

How long it takes to screed a floor will partially depend on the size of the area screeded and the type of screed used in the project. In most cases, an average time of seven days is given for the screed to cure, if left undisturbed under a polyethylene sheet which is sealed at its edges. This may be longer if the temperature in the area falls below 10ºC in a 24-hour period.

When you come to us to install your screed floor, you will find that our liquid screed in particular does not take as long to be cured, and can be walked on just 24-48 hours after it has been poured. To learn more about how long it takes to screed a floor, either with a traditional screed or a liquid variety, contact us today.

7. Let the Floor Dry

After the floor has been cured, it will still need time to dry. Avoid letting vehicle traffic onto it and avoid installing any other layer of flooring on it for at least three weeks. Heavy traffic in particular should be avoided until all installations are complete.

On average, a screed floor should dry at a rate of 1mm per day. For more information about how long it will take to have a complete screeded floor, call us today and one of our trained members of staff will discuss the process with you.

How Much Does it Cost to Screed a Floor?

how to screed a floor

How much you need to screed a floor depends on several factors, from the price and quality of the screed used to the size and depth of the floorspace it is installed in. As the factors vary, it can be difficult to provide an exact price.

On our site, you will find our service for a quick quote on any screed flooring you wish to have installed, meaning that you will not have to put an estimate on the price of your new floor. If you have any more questions about how much it is to screed a floor, call us today and we can discuss the features of your property before you place your order.

Contact the Professionals

It can cost you time and money to attempt to screed a floor if you do not have the proper training, equipment or mix. If the process goes wrong, this can delay the installation and  means that you will lose money from your work budget trying to get it fixed. 

In order to avoid this, it is highly recommended that you get in touch with a professional screed installation service, to ensure that you are getting a quality floor that will last, no matter what you need it for.

Get in Touch With Us

If you have been looking for a fast, professional service to screed a floor for a work or domestic project you have, then contact ScreedIt today. We have years of experience in this industry and we love what we do, so we want our customers to receive the best of what we have to offer. That is why we do everything we can to keep every floor we install to the highest standards.

Get in touch with us today and we can discuss the specifics you need for your floor, before we begin our work.


Could rapid drying times be just around the corner?

There have been a number of notable research and product development achievements over the last decade which have shaped the screeding and underfloor heating markets. Largely speaking we are an industry driven by speed, precision and quality, fuelled by clients who need flat and flawless floors, fast.

Drying (or curing) times have been top of the agenda for a long time now and any manufacturer capable of bringing to market a product which can successfully draw the moisture out of screed, without affecting the quality of the finished product is sure to become the number one choice for contractors worldwide.

Speed is in the driving seat

It’s fair to say that while there are other variables in the product development mix (like sustainability and cost efficiency for example), it’s most certainly speed that’s in the driving seat.

Speed of installation and speed of drying are the two magic ingredients to laying screed. As a contractor, we can facilitate rapid effective installation by employing the best installers and using the highest quality materials, but when it comes to fast-drying, that’s down to the manufacturers.

Are we on the cusp of a drying time revolution?

Word on the grapevine is that one of the UK’s leading screed manufacturers is on the brink of bringing to market a resin primer capable of making screed ready to receive floor finishes after only around 3% of its moisture has evaporated.

Typically speaking a liquid screed is 97% – 98% water and cannot be covered until moisture levels are below 75%. If we’re talking time, homeowners, self-builders, housebuilders and national contractors will only have to wait one to two weeks before furnishing their new floor, compared to the usual two month wait time.

That saving of around six weeks could drive forward refurbishment and build projects at a serious pace, and we all know that in the construction market, time is money.

The new resin primer has been independently tested by two external laboratories and has been passed to the relevant accrediting bodies before being introduced to the market. Watch this space.