Insulation Of Wooden Floors: An Overview Of The Technology Of Thermal Insulation Works

Heat loss in the house is not only through the walls and roof, but also through the floor. Losses are especially high in floors made of natural materials. That is why insulating a wooden floor helps to make the house warm, reduce or eliminate heat losses and save on heating bills.

The temperature in the living room must be at least +18°C and in children's rooms +20°C as required by the regulations. To achieve these indicators during the winter period, it is necessary to insulate the floor.

Today, due to the abundance of materials, there are many technologies for thermal insulation works. Let us consider the most popular of them.

Content of the article:

  • Ways to insulate wooden floors
    • Substance #1 - insulating floors along the floorboards
    • Option #2 - insulating across the rough floor
    • Option #3 - using polystyrene foam slabs
    • Option #4 - system a warm floor system
  • A few words about the materials
  • Hints from the experts
  • Conclusions and a useful video on the topic

Ways to insulate wooden floors

The choice of technology depends on many factors, namely: room type, ceiling height, type of covering, thermal conductivity of materials, budget, and occupant requirements.

One of the key factors is the type of wood flooring. There are three types:

  • parquet;
  • board;
  • plywood.

Plywood or OSB boards are most often laid on planks. Plywood floors are usually used as subfloors, less often laid on top of lagging. These two types of floors may be insulated with any technology.

Special parquet strips or individual parquet boards are laid both on concrete and on wooden foundations. Such a floor can be insulated with screed, any wood insulation, foamed plastic or foam plastic.

Let's look at the most popular technologies for insulating wooden floors.

Method #1 - floor insulation on joists

This is the most common method of thermal insulation, especially if the floor is close to the ground. With this method you avoid high heat losses.

Floor insulation is most often used to insulate floors in private houses.

Insulation of wooden floors: an overview of the technology of thermal insulation works

Floor insulation on joists is a simple and efficient method that is best suited for floors that are not protected from the ground. The chart shows the complete, approximate thermal insulation scheme

The works are recommended in the following sequence:

  1. T-split t-shaped wooden beams 45-70 cm apart, on which the floor boards are fixed with special screws.
  2. The selected thermal insulation is placed as tightly as possible between the beams and the gaps are filled with sealant or foaming foam.
  3. Following this, a vapour or water barrier is laid on top of the thermal insulation.
  4. Finally the floor boards are fitted and then treated.

It is very important that there is a ventilation gap of ~20-30mm between the insulation layer and the boards.

If you decide to use mineral wool or ecowool as insulation, then a vapour barrier is needed. It should be laid with an overlap of 10-15 cm and the edges should be up to 10 cm high. Special professional materials may be used, e.g. membrane vapour barrier or a polyethylene film.

For detailed instructions on how to insulate the floor on the joists see this material.

Option 2 - thermal insulation on the screed

This is ideal for rooms with high ceilings. The technique is slightly similar to the previous one.

The differences are as follows:

  • Sidewalk boards are fastened to the floorboards;
  • Finish up the boards with screws or nails;
  • Consider the size of the boards to be the same distance between the boards;
  • When all the boards are installed, you cover the rough floor surface with a vapour barrier. For example, a film or parchment;
  • then between the boards lay the thermal insulation, preferably without gaps;
  • after that again the vapor barrier sheets, and as the final step, cover the treated boards;
  • the clean floor can be covered with a special solution for gloss or lay some coating.
If you want to insulate an existing, good quality wooden floor, you can use it as a subfloor and lay a layer of insulation on it, but in this case the distance between the floor and the ceiling will be significantly reduced.
Insulation of wooden floors: an overview of the technology of thermal insulation works

The underfloor insulation technique is also called the double floor system. As the existing floor is not removed, but all layers are laid on it and covered with new boards

Option No. 3 - use of expanded polystyrene boards

This is the simplest thermal insulation scheme. This option is suitable even for rooms with low ceilings, as the thickness of the material is not very high.

Insulation of wooden floors: an overview of the technology of thermal insulation works

The scheme of insulation using polystyrene foam boards is quite simple, but of high quality. It is difficult to make a mistake when performing it, so anyone can handle it

The laying technology consists of several stages:

  1. A layer of insulation should be laid on a level covering/foundation. For example, polystyrene foam or mineral wool.
  2. If the foundation is uneven, it should be levelled in advance with a cement mix.
  3. Polystyrene foam plates 50 mm thick are laid in one layer if it is an apartment.
  4. The boards do not need to be fixed additionally.
  5. Then the thermal insulation should be covered with a layer of vapour barrier if it is a first floor or the installation is on the ground.
  6. After that two layers of plasterboards are laid and fixed with normal screws. A cement screed or plywood sheets can also be used.
  7. The cement screed should be laid in two layers, and the insulation should be covered with polyethylene film to prevent the screed from penetrating between the boards.
  8. After the final drying of the screed, the finishing floor can be laid.

If laminate is laid, a special thin substrate should be used under it. All layers of materials are laid with a gap in the joints.

T screed is used as one of the layers of insulation. Dry screed is used only after wood shrinkage, sometimes this process takes quite a long time.

From a physical point of view, the screed is a mixture of cement and sand in different proportions. There is a ready-made product in stores, but it can be created by yourself. It requires increased waterproofing, as it can deform because of moisture.

Floating screed is slightly different from the previous one. Although it also consists of a mixture of cement and sand. It is poured directly on the sheets of insulation  and therefore does not have a close bond with the floor.

Foam plastic or a material similar to it is most often used as insulation with a floating screed. This type of insulation is rarely used for wood floors.

Insulation of wooden floors: an overview of the technology of thermal insulation works

Some types of insulation are made in the form of boards. For example, gypsum fiberboard or gypsum plasterboard. This form of materials is very easy to use, and to cut it you need a regular construction knife

Option #4 - underfloor heating system

Water underfloor heating can be installed directly on the wooden base. If the boards are rotten, they must be replaced. The work requires plasterboard or GFB (gypsum fiberboard), a foil backing, a thin pipe, equipment for water supply and heating.

Please note that the underfloor heating should not be placed under large-sized furniture. As sofas and cabinets will heat up, and energy efficiency may drop.

Electric underfloor heating system requires the installation of special heaters under the finish. It is better to entrust complex works of this plan to specialists.

The whole system is powered by the mains, so it is worth protecting yourself against power surges and unscheduled power outages.

Insulation of wooden floors: an overview of the technology of thermal insulation works

Warm floor is a great solution for large rooms in a private home. Such flooring, if properly maintained, will last more than 10 years

The installation of such flooring, both water and electric, is quite time-consuming and complicated, as well as costly.

Technique for carrying out the work:

  • Lay layers of foil backing foil upright on the wooden floor and secure it with a construction stapler;
  • Lay sheets of 9.5 mm thick plasterboard on it and secure them with screws;
  • Lay a tube of sewn polyethylene, securing it with special plastic clips;
  • special fixing mats or reinforcement mesh can be used as a substrate under the pipe;
  • fill the structure with plaster flooring;
  • the last step is to assemble and install the pump and mixer unit and connect the whole system.

There may be several pipes connected to the boiler within one room. Each of them forms a circuit. These circuits can be included one at a time if the room is large, or all at once.

Detailed instructions for installing a warm floor on a wooden floor read more.

We have considered the most popular technologies for insulating wooden floors. Each of them has its own advantages. The technology also determines the type of material that is best suited for the work.

A few words about materials

Today there is a large variety of thermal insulation materials on the market. We will look at the most popular and commonly used ones.

Insulation must have a certain set of qualities. Therefore, you should pay attention to: weight, environmental friendliness, thermal conductivity, compressive strength, moisture resistance, service life. In addition, the insulation must have an average or better a high adhesion to the wooden surface.

Insulation of wooden floors: an overview of the technology of thermal insulation works

The thermal conductivity values of popular insulators according to SNIP. The lower the value, the warmer and drier the room will be

Also one of the criteria for insulation selection is its thickness. This indicator is critical for residents of high-rise buildings.

In addition, the choice of material is influenced by the type of foundation and flooring, the presence of the basement, as well as the features of operation - permanent housing or cottages.

Wool (mineral, stone, glass wool). This material requires good waterproofing as any wool quickly gets wet.

Insulation of wooden floors: an overview of the technology of thermal insulation works

Mineral wool is one of the most affordable materials for insulating wooden floors, it is unpretentious, easy to work with and has excellent thermal properties

The most commonly used mineral woolin combination with good waterproofing is for insulating wooden floors. Minwool is available in rolls and pressed slabs. It is quite easy to work with as it is light and easy to cut.

For insulation of the first floor it is worth using 20-30 mm mineral wool, and for the second floor and above - 10-15 mm.

The classic insulation consists of laying mineral wool between joists or directly on the subfloor.

Another popular insulator is sawl. They come in several varieties: wood, sawdust pellets, sawdustcobiton, arbolite. They require very good quality waterproofing. Need to use prepared sawdust, which were stored in a dry place for at least 5-6 months. This material is better not used for insulation of residential premises, as it quickly gets wet and starts to wither.

Sawdust, for the sake of reducing heat loss, should be laid in a thick layer, not less than 30 cm. This is the best option for insulating dachas or outbuildings.

An equally popular material is ceramsite, which is made from clay. It is a cheap and environmentally friendly insulation. It is most often used for dry screed or simply placed on the subfloor or between joists.

Insulation of wooden floors: an overview of the technology of thermal insulation works

Grained expanded clay should be placed in a thick layer. It should be approximately 5 times larger than wool-based insulation

Foam or extruded polystyrene foam  can be used in rooms with high levels of humidity.  These materials are quite dense in structure and sheets of various thicknesses can be purchased.

Polyurethane foam can also be used as a thermal insulation material. Special spray equipment is used to lay it. It can be used on any foundation and the foam itself can last up to 10 years.

Penofol is a rather popular Russian-made thermal insulation material. Thermal insulation sheets with a dense reflective foil. Available in several types. The classic version is made in the form of sheets of polyethylene foam coated with foil. There is also a self-adhesive Foofol C, one side of which is covered with a moisture-resistant adhesive and an anti-adhesive film, while the other side has aluminum foil.

Popular also considered fibrolite, which has excellent noise insulation. It is made of sawdust poured with a liquid cement mortar. It is available in the form of boards.

IOLON insulation is available in rolls and has low thermal conductivity. It comes in the standard silver color, but other bright colors. It has excellent noise insulation while the sheets are quite thin.

The most common use of insulation in the form of rolls, so they are easy to lay.

Insulation of wooden floors: an overview of the technology of thermal insulation works

Isolon in rolls should be laid in lap, not in the joint. You can seal the joints with bitumen mastic or polymer glue

Good advice from professionals

If you are planning to insulate yourself, please read the advice from professionals:

  • all gaps should be treated with sealant or foam, otherwise there may be additional heat loss;
  • if you are laying several layers of insulation, it is worth considering that each new layer should be laid perpendicular to the previous one;
  • materials for thermal insulation of the first and second floors of one house may differ;
  • to protect the wooden floor against groundwater, it is worth using as waterproofing an ordinary building film around the entire perimeter. It must be fixed with sealant;
  • Damp-proofing may be done with PVC boards or ruberoid or with ordinary polyethylene film or isoplastic membrane;
  • Some experts recommend installing vapor barrier after installing insulation. A film, parchment or other suitable material can be used as a vapor barrier.

Before purchasing all materials for the insulation work, it is advisable to consult with experts.

Conclusions and useful videos on the topic

A few video examples of how you can insulate the floor with your hands and for professionals, for beginners.

The video provides an overview of one of the technologies for insulating a wooden floor in a cottage or country house:

Native and inexpensive floor insulation technology that anyone can handle:

We looked at the most popular technologies for insulating floors and types of thermal insulation materials. If this is relevant for you, you can choose for yourself the right option. But before the final choice consult with a specialist and remember that cheap - is not always bad.

You know another way to insulate a wooden floor? Please tell people who are facing this question for the first time about it. Leave your comments, ask questions, share your experiences in the box below.

Leave a Reply

Your email address will not be published. Fields marked with * are required. *