Good insulation under underfloor heating is important to efficientlyënt use of your of your heated floor and the minimize heat loss. We'll explain in this blog what you moet on about insulation under your floor heating. There isand themesdiscussed, such as: different types of insulation, characteristics of good insulation, steps for installing insulation with underfloor heating, what are the costs and what savings do you have.
Table of contents
- The importance of insulation under floor heating
- Types of Insulation for Underfloor Heating
- Insulating the Floor and Crawl Space
- Characteristics of Good Floor Insulation
- Underfloor heating self-assembly
- Costs and Savings
- How Much Insulation Is Needed?
- Steps for Installing Underfloor Heating and Insulation
- Benefits of Good Floor Insulation under Underfloor Heating
- R Floorzz's underfloor heating panels and insulation
- Easily lay your own underfloor heating with R Floorzz pre-milled underfloor heating plates
- Where can you order a complete floor heating kit?
- Need help installing underfloor heating yourself?
- The 7 essential tips for laying underfloor heating
The importance of insulation under floor heating
Types of Insulation for Underfloor Heating
There are different types of insulation materials to insulate your floor heating or crawl space. To get good insulation directly under your floor heating, insulation boards are very suitable. There are several types of boards, such as PUR insulation boards, XPS insulation boards, glass wool boards and PR insulation boards. These materials can be used for both concrete floors and wooden floors.
A number of materials exist to insulate a crawl space. The most common materials for bottom insulation are the following types:
Insulating shells are shells found on the beach, with the smallest shells being ideal for soil insulation. With a thick layer, you get natural insulation in the crawl space because the cavities are filled with stagnant air.
HR++ or EPS beads are plastic beads that are injected into the crawl space, leaving a substantial layer on the floor. The material retains its insulation value and is resistant to moisture, mold and acids.
Insulating mattresses are plastic bags filled with insulating balls. These insulation mattresses are ideally suited for crawl spaces where there is often a layer of water. They float while maintaining the insulating effect of bottom insulation.
Insulating the Floor and Crawl Space
Insulating your home's floor or crawl space is a good investment. It reduces heating costs and makes you feel comfortable: you will never suffer from cold feet again. Insulating the floor and crawl space (also called bottom insulation) seems the same because both methods insulate the space under the floor. Yet the two forms of insulation differ. With floor insulation you place the insulation material directly under the floor, while with bottom insulation you place the insulation material on the bottom of the crawl space.
To install floor insulation, sufficient space under floor is important to fix the insulation material safely under the floor. For a wooden floor, you need at least 35 centimeters under the joists to attach the material. A concrete floor requires a minimum of 50 centimeters. Based on the year of construction, you can make a good estimate of whether your house has already received floor insulation.
When a home does not have a crawl space or it is not accessible, it is possible to install floor insulation under the floor covering. The current floor covering must then be removed, which is an ideal time to install floor heating. For this method of floor insulation, there are roughly two ways of insulating:
- A floating floor is installed on top of an existing bearing floor. Insulating material is placed between the ground floor and the screed. Not only does this save energy, it also acts as sound insulation. Especially for apartments, this is a good bonus.
- When a new floor is installed, the underside of the floor is fitted with insulating material. An insulating underlayment is one example.
When you want to install floor heating, it is the ideal time to insulate the floor. Floor insulation is also very important in this case because it prevents heat leaking under the floor. With the right floor insulation, all the heat goes into your house and you make optimal use of your floor heating.
Characteristics of Good Floor Insulation
The most important feature of good floor insulation is the insulation value of the material. This insulation value is expressed in Rd value. Rd stands for Resistance Declared, which stands for thermal resistance. Thermal resistance is related to thermal conductivity. Because if thermal conductivity is high, then thermal resistance is poor and the material has no insulating capacity. Conversely, if thermal conductivity is poor, then the thermal resistance is high. And thus the insulation capacity. Air and plastics, among others, are poor thermal conductors and are therefore often used as insulation materials.
The insulation value of floor insulation materials depends on the thickness of the material. The table below shows this clearly.
| Insulation material | Thickness (Rd value 1.5) | Thickness (Rd value 2.5) | Thickness (Rd value 3.5) | Thickness (Rd value 4.5) |
| PUR foam (closed cell) | 5 cm | 8 cm | 10 cm | 13 cm |
| Rock or glass wool | 6 cm | 10 cm | 14 cm | 16 cm |
| PUR foam (open cell) | 6 cm | 10 cm | 14 cm | 18 cm |
Source: Regional Energy Desk
Underfloor heating self-assembly
Costs and Savings
The cost of floor insulation and bottom insulation is of course different for each situation. If you outsource the insulation to a professional, floor insulation that you install directly on the underside of the floor costs between 30 and 40 euros per square meter. This includes the cost of installing the insulation material and VAT. The costs for bottom insulation are lower, between 25 euros and 35 euros. The exact cost of insulation depends on the type of insulation material, the area you want to insulate and the condition of the crawl space.
We have listed the costs for each housing type in an overview.
| House type | Floor Area | Floor insulation price | Price bottom insulation |
| Apartment | 60m² | €1.700* - €2.400* | €1.200* - €1.700* |
| Courtyard | 52 m² | €1.500* - €2.200* | €900* - €1.400* |
| Semi-detached / corner house | 65 m² | €1.900 - €2.500* | €1.300 - €1.800 |
| Detached house | 98 m² | €2.800 - 3.600* | €2.000 - 2.600* |
*Prices include installation and VAT
It is good to know that with floor insulation and soil insulation, you should consider the cost of the following materials:
- Vapor barrier film for a damp soil
- Vents that provide adequate ventilation
- Making a hole in the floor (or foundation) to the crawl space, if it is not already there
- Draining the crawl space
- Debris clearing and disposal
If you get started insulating your floor yourself, the costs are different. You then have to deal mainly with material costs. For floor insulation, consider the following costs:
- 14 centimeters of glass or rock wool: 10 to 12 euros per m²
- 15-centimeter EXP or EPS insulation boards: 12 to 16 euros per m²
- 14 centimeters of hemp wool: 18 to 22 euros per m²
- Insulation film: 15 to 17 euros per m²
If you go for bottom insulation, biopearls of 20 to 30 centimeters cost between 12 and 16 euros per m².
Investing in floor insulation and ground insulation also pays off, of course. Besides warmer feet in the house, floor insulation also saves between 10% and 15% per year in heating costs. If you still have radiators and you use, say, 1,500 m³ of gas per year at a gas price of €0.76 per m³, then the savings with floor insulation are easily between 115 and 170 euros per year. If you have underfloor heating without floor insulation, then you can save even more because you lose a lot of heat to the crawl space.
To save money with floor insulation, it's a good idea to also consider the following for exact savings on your gas bill:
- Property type: apartments and mid-terrace houses lose relatively more heat through the floor than a detached house
- The floor area to be insulated
- The heating behavior
- The choice between bottom insulation or floor insulation
To make the yield and return transparent, we have prepared the tables below. It is worth noting that in this calculation we use a gas price of €0.76 per m³. We also take into account the gas price increase of 1% and a (general) inflation rate of 2% per year. The increase in home value with floor insulation or ground insulation is not included, because you have fewer fixed expenses.
The first table shows the costs and savings of floor insulation and the second table shows the same for bottom insulation.
FLOOR INSULATION EFFICIENCY
| House type | Floor Area | Cost | Annual savings | Payback period | Yield* |
| Apartment | 60 m² | €2.052 | €250 | 6 to 8 years | 6.5% to 8% |
| Courtyard | 52 m² | €1.850 | €250 | 5 to 8 years | 7% to 8.5% |
| Semi-detached or corner house | 65 m² | €2.200 | €150 | 9 to 12 years | 5% to 6.5% |
| Detached house | 98% | €3.200 | €150 | 13 to 17 years | 5% to 6.5% |
*The return is calculated on the minimum lifetime of floor insulation, which is 25 years
BOTTOM INSULATION EFFICIENCY
| House type | Floor Area | Cost | Annual savings | Payback period | Yield* |
| Apartment | 60 m² | €1.450 | €200 | 6 to 8 years | 6.5% to 8% |
| Courtyard | 52 m² | €1.150 | €200 | 5 to 8 years | 4.5% to 5.5% |
| Semi-detached or corner house | 65 m² | €1.550 | €125 | 9 to 12 years | 5% to 6% |
| Detached house | 98% | €2.300 | €125 | 14 to 18 years | 5% to 6% |
*The return is calculated on the minimum lifetime of floor insulation, which is 25 years
Requesting a quoteHow Much Insulation Is Needed?
When you install floor heating, you want to avoid heat escaping downward. We recommend greater thermal resistance (R-value) than floor insulation without floor heating, resulting in greater thickness of floor insulation. Ideally, at least 8 inches of floor insulation should be installed under the floor heating. Of course, this does depend on the build-up height available under the floor.
The ideal thickness of insulation depends on the insulation material you use. Floor insulation with sprayed PUR foam is a cheap and fast way to insulate your floor. With this material as floor insulation, a layer of 9 or 10 centimeters gives you enough insulation value for an underfloor heating system for a small space.
In addition to sprayed PUR, hard, pressure-resistant boards with PUR or PIR are also available as a material for floor insulation. Here, however, it is important that the boards are placed on a level surface. A filling layer to hide pipes is required. The biggest advantage is the good thermal insulation with a small thickness. From 8 or 9 centimeters you already have a better floor insulation than with sprayed PUR.
Another method of floor insulation are insulation boards in EPS, better known as Styrofoam insulation boards. EPS floor insulation boards are cheaper than PUR or PIR boards, but the insulation value is also lower. In short, you need a greater thickness to achieve the same result, which is at least 11 to 13 inches. Styrofoam boards are very light, easy to work with and simple to cut to size.
In addition to the above plastic materials, you can also use mineral materials as floor insulation, such as gllaswool or rockwool. Of these environmentally friendly floor insulation, you do need more insulation thickness.
Steps for Installing Underfloor Heating and Insulation
Installing your own underfloor heating is easier than you might think. As with many other jobs, good preparation is half the battle. There are a number of things you should pay attention to before you start installing.
Floor insulation
Good floor insulation or bottom insulation is important to use your floor heating efficiently. Good floor insulation ensures that no heat is lost under your home. To determine which floor insulation or bottom insulation you can use, it is important to determine how much space you have under your floor. Different materials for floor insulation depends on how much space you have in the crawl space. The accessibility of the crawl space is also important for your floor insulation.
Lay pattern
You always lay an underfloor heating via a particular laying pattern. In this way, the heat is distributed evenly and you avoid cold zones. In this way, you get the most out of your underfloor heating. At Rfloorzz, we are happy to help you make a good laying pattern.
Supplementary or main heating
It is important to consider carefully in advance whether you want to use the underfloor heating as main heating or supplementary heating. This affects the distance between the pipes. For main heating this distance is 10 centimeters, while for auxiliary heating this distance is 15 centimeters.
Flooring
To make the most of your underfloor heating, it is important to choose the right flooring. Here it is best to choose tiles, concrete or cast floors. But floor coverings such as PVC, laminate and vinyl are also good to combine with underfloor heating.
Calculate costsBenefits of Good Floor Insulation under Underfloor Heating
Good floor insulation is essential to enjoy your underfloor heating to the fullest. One of the main benefits of floor insulation is energy savings. Because the heat does not leak into the crawl space, the underfloor heating retains heat in the room and does not have to work as hard. With this, floor insulation helps improve your home's energy rating, making it worth more.
Good floor insulation also prevents rising damp from coming into contact with the floor elements and the floor itself. This also keeps the living spaces free of moisture and prevents condensation moisture. Condensation occurs when warm air comes into contact with a cold surface, causing moisture.
R Floorzz's underfloor heating panels and insulation
The underfloor heating plates from R Floorzz are the right plates for your floor. You can easily install them yourself, they are suitable for all subfloors, are delivered ready-to-use and provide higher energy absorption and release. Simply request a quote or start a cost calculation on our site andn order the required boards, so you will have warm feet in your home soon!
Is insulation always needed with drywall underfloor heating?
Yes, with both drywall and other underfloor heating options, it is a good idea to lay insulation. Insulation helps preserve heat and reduce energy costs. You can place insulation under the floor heating or choose to install it in the crawl space. To make this process easier, R Floorzz has floor elements developed that already have insulation.
Installing floor heating yourself
So when you are going to lay your own underfloor heating, R Floorzz's underfloor heating panels are the right option. They are simple to install (within one day), are efficient and, through the included insulation, ensure you keep warm feet. Need more information about these plates? Then click here.
Having floor heating installed
Do you still want to have your underfloor heating installed? You can! At R Floorzz, we're happy to help you lay your underfloor heating. Our team of expert installers will make sure that the underfloor heating is installed correctly, so that you can optimally enjoy comfortable warmth in your home. Whether you want underfloor heating installed in your living room, bathroom, kitchen or any other room, we are here for you. Contact us and ask about the possibilities!
Waterborne underfloor heating or electric?
Electric or water-based floor heating is a big and important choice. Both have their advantages, but which one is most suitable for your situation? For specific information for your situation, we encourage you to contact us, but in short, you can see it as follows: Gas (water-based) underfloor heating, is by far the most suitable for larger rooms and possible cooling options. In contrast, electric floor heating is especially interesting for small spaces.
Can underfloor heating be used on a wood floor?
Yes, underfloor heating is possible on a wooden subfloor. R Floorzz's underfloor heating boards are ideally suited for this application. Whether it is an old house, floating floor, renovation project etc. The underfloor heating plates from R Floorzz are an ideal solution. You can get them already fully pre-milled, which saves a lot of hassle with milling, renting and mess. Request a quote, or view our plates at estrichvloer.co.uk
Requesting a quoteEasily lay your own underfloor heating with R Floorzz pre-milled underfloor heating plates
With R Floorzz's pre-milled underfloor heating plates, you can easily install underfloor heating. R Floorzz has different systems for on existing subfloors.
Do you want to mount on a wooden subfloor on a ground floor or do you want a system with noise reduction? Both are possible to install yourself.
View floor heating platesWhere can you order a complete floor heating kit?
You can order a mono floor heating kit from R Floorzz at rfloorzz.co.uk or the webshop estrichvloer.co.uk
Need help installing underfloor heating yourself?
Do you need help installing underfloor heating? Or do you simply want to outsource it? Get in touch or make an appointment.
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