Concrete base for underfloor heating – pitfalls: how to avoid unnecessary expenses

Do you intend to use a concrete base for underfloor heating installation? It’s an excellent method for heating your house comfortably and efficiently. To save costs and guarantee a smooth installation process, there are some traps to watch out for.

Inadequate insulation under the concrete slab is one of the main hazards. Heat can escape downward rather than warming your floor and room if you don’t have enough insulation. This inefficiency raises energy expenses in addition to lowering the comfort level in your room. Always make sure that a premium insulation material appropriate for underfloor heating is installed beneath the concrete base to prevent this.

Inadequate placement and spacing of heating cables or pipes within the concrete is another frequent problem. Inadequate planning may cause hot and cold spots on the floor due to an uneven distribution of heat. This wastes energy in addition to having an impact on comfort. To lessen this issue, carefully consider the manufacturer’s recommendations when arranging your underfloor heating system, and think about seeking professional advice to maximize the design.

Utilizing an improper or inferior concrete mix can also be harmful. For underfloor heating bases, the concrete used has to be able to support structural integrity and efficiently conduct heat. The incorrect mixture can cause cracking, uneven heat distribution, and even the eventual need for expensive repairs. Use only concrete mixes made especially for underfloor heating applications; these mixes usually contain additives to increase durability and thermal conductivity.

Improper setup Problems may also arise from the concrete’s heating element depths. The efficiency and efficacy of the heating system may suffer if the pipes or cables are buried too deeply or too near to the surface. Over time, this may cause the system to become damaged and result in uneven heating. To guarantee the best possible performance and longevity of your underfloor heating system, carefully adhere to the manufacturer’s installation depth recommendations.

Finally, the integrity of the entire system may be compromised if the significance of a suitable curing process for the concrete is disregarded. Concrete can reach its maximum strength and thermal properties when it is properly cured. This step can be rushed or ignored, which can result in shrinkage, cracking, and reduced heat transfer efficiency. Give the concrete enough time to cure in accordance with the manufacturer’s instructions, and think about applying curing compounds or techniques to guarantee ideal circumstances for your underfloor heating system.

You can successfully install a concrete base for underfloor heating without needless expenditure if you are aware of and steer clear of these pitfalls. In addition to improving the comfort and efficiency of your heating system, taking the time to plan, use high-quality materials, and adhere to best practices will also result in long-term savings and satisfaction.

Necessary concepts

Let’s define a few terms so that we can comprehend how concrete can be used for underfloor heating. It’s critical that we understand the differences between the various kinds of underfloor heating systems, the levels and uses of screed, and the installation techniques.

Classification of TP (underfloor heating)

At the moment, the market offers several different systems mounted in the horizontal plane of the floor. Some are used as the main heating, some only increase the level of comfort in the room.

Water and electric systems are used for heating. The heating element used to differentiate the latter.

The following components are the basis for the electric horizontal heating systems that can be installed:

Stages of work on pouring screeds

The screed is made multiple times in conjunction with the installation of a horizontal heating system.

We split the pouring into three stages to help you understand the procedure:

1. Rough screed. Applied to the intended base for leveling. Performed if necessary.
2. Leveling screed, which is poured over the thermal insulation material. The system is directly installed on this layer.
3. Finish pouring. This is pouring over the heating system. Arranged if necessary.

Types of screed

Apart from utilizing concrete mortar for floor pouring, there exist alternative options for screeds, which require installation of varying levels in addition to different heating systems.

Three different kinds of screeds are utilized when putting in underfloor heating:

• Wet screed: the usual method of pouring concrete or cement-sand mortar.
• Semi-dry screed: leveling the floor with a ready-made composition, a certain degree of humidity.
• Dry: an ideal way to level the floor, recommended only as a rough layer.

Water heated floors

Although one of the most cost-effective solutions available, a water floor heating system is expensive and challenging to install. It is crucial that you adhere to the technology when installing it. Concrete fills the system, making it extremely difficult to fix any flaws after pouring.

The reason screed is used for water floors

• surface leveling;
• elimination of defects affecting heat transfer;
• formation of the heat distribution process;
• fixation of heating elements.

Wet screed

The traditional form of this heating system is concrete for water-heated floors.

The benefits of this type of installation are that it simultaneously forms the surface and pours the solution, creating:

• a heat-insulating layer that allows to significantly reduce losses of energy use;
• a flat surface that can withstand significant weight loads;
• a system of uniform distribution of heat energy is formed.

The installation of this system is predicated on the completion of the warm water floor concrete pouring.

Composition

The grade and composition of the concrete used for a warm water floor are critical considerations when installing underfloor heating. Since the screed will be subjected to continuous thermal loads, its strength should be maximized while preserving its plasticity.

It is advised to use: for this.

• not sand, but screenings with a fraction of 3 – 5 mm;
• cement M300 and higher;
• plasticizers;
• fiber.

The generally accepted guidelines state that concrete for a warm floor in residential buildings must be at least M150 grade, and for industrial areas, M 300 grade or higher.

Important points when installing a rough screed

The final surface after the rough fill needs to fulfill the following specifications:

• The corners of the floor and walls must be strictly at an angle of 90 0 – for proper adhesion of the heat insulator and damper tape.
• The sector of one heating circuit should not have a depression or bulge more than 5 mm.

The rough floor needs to be primed and cleaned of dust and debris after it has dried. It is necessary to level and putty the walls. As soon as the walls and floor are ready, a damper tape is used to secure the perimeter of the thermal insulation layer, which is then covered in a reflective film.

A room plan should include a pipe layout diagram showing where all control and monitoring components are located before the water floor pipes are installed. Bridges constructed of boards or panels are a better option for ensuring safe floor movement after the pipes have been installed.

Calculation of concrete composition

Semi-dry screed

The primary characteristic that sets semi-dry screed apart is its composition, which has a lower humidity and notably less water in it. It is simple to verify the solution’s quality with your hands.

Squeeze a tiny bit of the mixture into your fist. The resulting lump should remain solid and not crumble or leak water. The image displays the proper consistency in composition.

Some benefits of semi-dry screed over concrete pouring are as follows:

• lower cost;
• easy to level the surface;
• the heat and sound insulation characteristics of such a floor are much higher;
• does not shrink when drying;
• the readiness period is much shorter.

Dry screed

On top of the waterproofing material, specific bulk compositions or materials are used for installation. Concurrently carries out the insulation functions.

In contrast to the traditional screed, it offers the following benefits and drawbacks:

• Does not require special construction skills during installation;
• There is no time limit during the backfill process, you can stop at any stage. The liquid solution must be poured in one go;
• Instant readiness for further work, no need to wait 28 days for drying;
• More often than others, expanded clay is used during installation, which is an excellent heat insulator;
• Technical communications and electrical wiring can be “hidden” in the backfill layer.

• Dry backfill is an excellent place for rodents and insects to breed.
• In case of a leak, water soaks into the dry layer, which leads to the formation of fungus and mold;
• Very low load-bearing capacity: there is no possibility of arranging additional walls or partitions.

Size of the screed

Whatever the kind, the primary prerequisite remains the same: the thickness of the concrete at the base and above the heated floor must be constant across the whole space. This is crucial because, in the absence of it, heating and heat transfer will occur on multiple levels, destroying the floor pie.

Bottom

The concrete warm floor is installed over a coarse screed with a minimum thickness of 5 mm. The type of solution has a major impact on the fill layer’s size.

Note: You should move a portion of the floor pie under the rough fill if the base is in good condition and the thickness of the rough screed is low.

As soon as the fill dries, you can begin laying the warm floor by shifting the water barrier and thermal insulation beneath the rough screed. You will actually save a ton of time.

The whole pie

Under concrete, a heated floor is typically installed. When using a traditional cement-sand mixture, the fill has a thickness of 50 mm. The thickness drops when fillers and a plasticizer are added.

With a water heating system, you can roughly determine the floor pie’s size. Depending on the floor, this size will range from 8.5 cm to 11 cm in city apartments when taking into account the installation of the thermal insulation material.

Crucial! You need a special permit from the heating network in order to install water systems connected to central heating in apartment buildings.

Concrete volume calculator

Electric floors

Everything is much simpler, but requires more operating costs, when floor systems are heated by electricity. The room’s height is not compromised when installing an electrical system on a concrete floor because the mats are only a few millimeters thick.

Modern IR floors, on the other hand, don’t need an upper screed to be installed; you can safely lay decorative roll or sheet material over them.

Speaking of which, The cable system has a 30 mm thickness, which can be lowered by a third by using plasticizer.

Careful planning is necessary when building a concrete base for underfloor heating systems in order to prevent expensive errors. This article examines typical mistakes like improper insulation or improper pipe placement that can result in needless costs. Through comprehension of these possible problems and adherence to recommended procedures, homeowners and contractors can guarantee effective heating operation and prevent the eventual need for costly maintenance or substitutions. With the help of this guide, readers should be able to install an underfloor heating system that is both dependable and reasonably priced, from selecting the right materials to using the right installation techniques.

Pouring technology

After resolving the complexities and subtleties, we will talk about how to maintain a warm floor. The room should be between five and twenty-five degrees Celsius when working on the floor installation. The base needs to be cleaned and emptied if it’s in good shape. A black screed is laid out if needed.

Preparation

The damping tape is glued to the subcooded walls and the prepared basis.

This is always done in order to:

• prevent heat loss to heat the walls;
• avoid the destruction of the screed as a result of temperature expansion.

If saving money is the decision, the same result can be achieved by laying foam, for example, around the edge of the heat insulation strips.

Crucial! Installing a thermal barrier is essential between the two systems as well as between the system and the wall. If the heating contours of the kitchen and the hallway differ, damper tape must also be installed where they converge.

Heat-reflecting material and a waterproofing film are placed on the floor following the thermal insulation of the joint area.

System installation

When installing a water floor or any other type of horizontal heating system by hand, make sure to precisely follow the manufacturer’s instructions. The components of the system itself are always included in the instructions. A cable or pipe that goes through the temperature seam needs to be covered with corrugated material for protection.

Warming elements are connected after the system has been laid and fixed. It’s important to make sure every component of the concrete system is functioning properly before pouring concrete. Work can proceed if the test launch was successful.

This article’s video will demonstrate how to install a water floor.

Finish pouring

Concrete mortar does not always need to be poured into the system from above. Other materials are occasionally employed for this.

• Some apartment owners, in an attempt to reduce costs and reduce the weight of the screed, try to pour heated floors with expanded clay concrete. What will happen if you pour heated floors with expanded clay concrete?
• The answer is nothing good. Expanded clay is a heat insulator. By adding it to the concrete solution, you significantly improve the thermal insulation properties of the screed. Therefore, it makes sense to install the floor system on such a base in order to avoid energy loss.
• There is no point in pouring underfloor heating from above with such a composition, because this will reduce the efficiency of the system. The fact is that the top layer of expanded clay will prevent heat from passing into the room. In fact, in this way, you will simply be wasting money.

Crucial! To minimize system operating costs, the layer into which floor heating is poured needs to have the highest possible thermal conductivity.

Although expanded clay concrete screed offers superior thermal insulation, a leveling layer is still necessary.

Calculation of concrete composition

Common Pitfalls	How to Avoid
Insufficient Insulation	Ensure proper insulation to retain heat and efficiency.
Poor Planning of Layout	Plan the layout carefully to minimize tubing and maximize heat distribution.
Inadequate Control System	Invest in a reliable control system for efficient operation and energy savings.
Low-Quality Materials	Use high-quality concrete and tubing to avoid leaks and repairs.

The comfort and energy efficiency of your home can be significantly increased by installing a concrete base for underfloor heating. But if they are not properly addressed, there are common pitfalls that can result in needless expenses. Inadequate insulation under the concrete slab is one of the main issues. Inadequate insulation allows heat to escape downward rather than warming your floor, which raises energy costs and consumption.

Make sure there is enough insulation installed beneath the concrete slab to avoid this potential hazard. By reflecting heat upward, this insulation increases the effectiveness of your underfloor heating system. It’s critical to install insulation correctly, following manufacturer instructions, and to use materials with the right thermal resistance (R-value).

The incorrect layout and design of the underfloor heating system could also be a problem. Ignorance of the consequences can lead to hot or cold spots, unequal heat distribution, and eventually even damage to the concrete slab. Make sure the heating elements are arranged precisely before installing them to guarantee uniform heat distribution throughout the room.

Furthermore, utilizing subpar or incompatible materials may result in additional costs and issues down the road. It’s imperative to use concrete mixtures made especially for applications involving underfloor heating. These mixtures are designed to be long-lasting and low-maintenance due to their ability to withstand the strain of heating and cooling cycles without breaking.

Finally, using the wrong installation methods can result in extra costs. Make sure the concrete slab is properly poured and allowed to cure in accordance with industry guidelines. This covers suitable finishing methods, sufficient curing times, and reinforcement. Taking short cuts during installation can lead to premature wear and tear or structural problems that will require expensive repairs later on.

You can maximize the longevity and efficiency of your concrete base for underfloor heating while averting needless costs by taking proactive measures to avoid these common pitfalls and making sure the installation is done by professionals. Long-term cost savings can be achieved by making investments in high-quality materials, careful planning, precise installation, and adequate insulation.

Video on the topic

Here is the correct thickness of the screed for underfloor heating

base for underfloor heating without unnecessary costs.

Warm floor without unnecessary costs.