Radiant Heat Under Wood Floor: Underfloor heating guide

One thing that most people forget about wood flooring is its natural material. Therefore, it’s susceptible to the surrounding temperature.

And while having a cool floor on the beach house can be nice, it can sometimes get cold. But thanks to the radiant heat under wood floor, now you can have the best of both worlds.

You can enjoy the gorgeous wooden floor while staying warm during autumn or even winter. However, not all heating method works for a wood floor.

Therefore, you need to have the right match between the heating method and the floor. A small mistake may cost you a lot.

Heating under wood floor

It is now possible to get heating under wood floor. However, you need to know more about the types and how to install them. You can choose between several methods to heat your floor. However, choosing one for a wood floor can be tricky.

As a natural material, people don’t associate wood with a heated floor, as it’s more common on tiles or concrete floors. So now it’s time to surprise everyone by showing a heated wooden floor. When you do it well, it’ll be an extra point for your house’s overall value.

Good heating under a wood floor can last up to 35 years. It needs to be set up perfectly and taken care of regularly to stay in good shape. In this case, perfect is possible and attainable. All you need to know is understand how to achieve perfection.

Can I use a radiant heater with a hardwood floor?

Yes, you can use hardwood floors to cover the radiant heater. However, if you choose engineered hardwood or laminate, you will have more options than a solid plank.

As you know, engineered wood consists of several thin slices instead of a solid cut. You can rely on their flexibility to get the overall look you want. Remember, insisting on using solid hardwood will severely limit your options.

You still need to check the grains and calculate how the wood will expand. It’s possible you don’t like the only wood options or can’t find a suitable alternative. So you must conduct thorough research on this matter and talk to a professional to know their assessment of the situation.

Pros and cons of radiant heat under wood floor

There are several pros and cons to having radiant heat for your wooden floor. Your opinion may change after you understand them. But that’s okay, and radiant heating is generally likable but not exactly applicable to all situations.

Let’s start with the cons first. Using radiant heat for a wood floor means you can’t use rugs or carpets on the floor. When you cover the wood floor, you are keeping a lot of heat underneath the floor. This puts the whole house at risk. Your floor may expand and break or even worse than that.

Another disadvantage of using radiant heat is that you have limited wood choices. Many floor fitters suggest you use laminate or engineered wood instead of solid hardwood planks.

Anyhow, the best part about using radiant heat is its durability. Compared to other methods, radiant heat is fairly easy to maintain, and you can use it for many decades.

Things to consider before installing heat under wood floor

Before you install your heating method for your wooden floor, you need to consider these things. You also need to include the pros and cons in your consideration.

Installation cost

First and foremost is the cost. In addition to the installation cost, you need to calculate the overall maintenance cost. Heating can cost you a lot if you choose the wrong wood and have to redo it.

Wood Types

Wood type plays a huge part in this situation. Radiant heat means the plank may be in direct contact with the heat. And it boosts their chance to expand and shrink dramatically.

Consider floor construction

Glued floorboards ensure an even heat transfer into the wood and onto the wood surface. Floating installation, often done with parquet floors, causes air pockets to form under the covering.

This makes the heating system take longer to react and work much less well. When designing the underfloor heating, you must consider which floor covering to use and how to put it down.

Only then will there be no unpleasant surprises about how well the system works, how comfortable it is, or any sources of damage.

Wood lives and changes

Wood is a natural material that keeps on living even after it has been installed. It takes in moisture and slowly gives it back to the air in the room.

People want the wood to be able to hold water. A solid wood floor gives off moisture in the winter and dry, low-humidity areas, but it takes it back up when it’s warm and humid. This keeps the temperature inside even all year long.

But this is accompanied by material swelling and shrinking. When it’s dry for a long time, and the relative humidity is below 30%, floorboards can get cracks from shrinkage.

A high relative humidity of 60% or more can cause mold to grow in the building and dampen the rooms inside. It can also cause wood to swell and cause the wood to bulge.

Wood is still a flexible material even after it has been cut down, stored, dried, and worked on.

This is also shown by the fact that many companies that make wooden floorboards say that the drill hole for the heating pipe holes should be about.

The heating pipe is 20mm bigger. So the floor will still be able to move.

DIY or ask professional

Talk to a professional about which wood is the best. Explore all of the options before you make any decision. See if you have any alternatives to the wood you like. Using a heated floor means you must be very picky with the wood and properly acclimate it.

How to install radiant heat under wood floor

How to heat a floor from underneath? After deciding to install radiant heat under the wood floor, it’s installation time. Make sure you have done all the prerequisite assessments on the necessary elements.

Anyway, installing the floor heater is a very straightforward process. Start with installing the wood sleeper, as it is the base for the heating floor.

Install the radiant heater of your choice. Add a cover layer for protection before you install your wood floor.

Wood is a natural material that changes depending on how humid the air is. It is important to ensure that wooden floors have the right amount of moisture and that the right heating cycle is set when installing underfloor heating.

The wood can be put down as a floating floor right on top of the floor heating or on a lath structure. For proper support, boards less than 20 millimeters thick should be propped up and fastened.

When putting the panels on top of the screed, it’s best to use impact sound insulation, which acts as an insulator so that heat can get to the floor covering well.

Despite sounding very easy, you should let professionals install the heater floor to avoid mistakes in installing underfloor heating. This will save you time as you can focus on other rooms while picking up tips or two from the professionals.

Underfloor heating structure and function

The floor needs to be set up correctly for the radiant heat systems to work well. So, if you want to remodel your house or apartment, you should look closely at your floors to see if they can be retrofitted with underfloor heating.

Don’t forget that the average height from the concrete floor to the covering is 92 mm when installing underfloor heating.

Most of the time, the base layer is a raw concrete slab. The intermediate layer is made up of a few different parts. If the concrete slab (basement or ground floor) needs to be sealed against rising dampness, this is usually done with a bitumen primer and welding sheets.

The floor’s necessary thermal insulation is then put on top of this layer. Most of the time, hard foam boards are used for this. When it is needed, impact sound insulation is put in place.

The next step is floor heating. This is put down in a special screed that flows. After the screed comes to the wear layer, the part of the floor is on top. This layer can be made of many different things, such as tiles, laminate, carpet, or vinyl flooring.

From the raw floor covering to the floor covering, the height of the underfloor heating installation is usually 92 mm. The thermal and impact sound insulation is about 30 mm thick, the heating pipes are about 17 mm thick, and the screed is about 45 mm thick.

Radiant Vs. Hydronic heating wood floor

First, let’s say that a real wood parquet floor can be used with underfloor heating. But there are some restrictions, which we’ll talk about below.

Underfloor heating usually comes in two forms: hot water heating, also called hydronic heating, and heating modules powered by electricity, like heating foils or mats.

The way a hydronic heating system heats is suitable for wood floors because it heats up slowly and doesn’t get so hot that it could quickly damage the parquet above.

With radiant heat, things are different. Depending on the version, the heat can build up much more quickly, and the highestomi temperatures can reach a point where the floor covering can’t handle it.

The temperature must be set so that the subfloor surface stays at no more than 80 degrees Fahrenheit. This is the minimum requirement.

In this case, check an electric heat system already in place or, for renovations and new construction, go straight for a model made to work over parquet, etc. Avoid buildings that are too thin if you want the heat to move around well!

Which wood floor covering is best for underfloor heating?

In theory, any type of floor covering can be used with underfloor heating. Some floor coverings are better than others because they don’t keep heat in or out as well as others.

The total thermal resistance of all the layers can’t be higher than 0.15 m2K/W.

You can get this information from the manufacturer or the floor covering package. Whether the floor is floating or fixed is also important.

With the floating version, a space of air is made between the covering and the screed. This air space makes it harder for heat to pass through. So, you have to consider that heating has more inertia.

Wooden parquet and cork floors have high thermal resistance, so they need heating that works well under the floor. Wood can grow or shrink when the temperature changes.

Because of this, there can be small cracks or joints that don’t look good. Full-surface adhesion can help joints come together.

Hardwoods like walnut, cherry, oak, and bamboo are all good choices. Softwoods like maple and beech shouldn’t be used.

Thermal conductivity varies depending on the type of wood

How thick can a wood floor be for radiant heat? The surface material is very important when figuring out how much heat underfloor heating will put out. In contrast to a heated screed, which might have a 10 mm tile and 5 mm of glue, wooden floors usually have a thickness of 20 to 30 mm.

The specific thermal conductivity, which is given as a number, is an important factor. This number can vary a lot depending on the type of wood.

Since they are denser than fir, spruce, Douglas fir, beech, and oak can store more heat than the softwoods mentioned above.

In addition to the wood’s density, thermal conductivity, and ability to store heat, its size also affects how well the system works.

Less thermal resistance means that the floorboards are not as thick. Depending on the system, this makes it possible to lower the flow temperature, which is good for overall energy use.

Types of wood floor for underfloor heating

What is the best wood flooring over radiant heat? Because different types of wood floors have different thermal properties, they aren’t all good for covering floors with underfloor heating.

The better a floorboard is at transferring heat, the denser and thinner it is. This makes it more likely to be used with an underfloor heating system.

Other wood floors can also be used, but if the wood is softer and less dense, the planks must be thick enough not to act as insulation and keep the heat out. As a general rule, the surface temperature of a wooden floor should not be more than 80┬░fahrenheit.

Heating the floor changes the amount of moisture in the wood, so you should choose a wood floor that can adjust to changes in temperature without changing the way it looks.

Radiant heat engineered wood floor and kiln-dried wood works best with the system, but you should always ask the floor manufacturer if it can be used with underfloor heating.

laminate floor

This synthetic floor looks like wood and is resistant to stains and scratches. Laminate is easy to put in and costs less than other options.

Most laminates can be used as a floor covering with underfloor heating, but it’s best to check with the floor manufacturer first.

Because the material is a good insulator, the heater may be slightly slower to respond and take longer to heat up.

Vinyl floor with underfloor heating

With floor heating, vinyl flooring is safe to use. Vinyl gets hot fast and cools down just as fast.

Above 80┬░F, you shouldn’t use vinyl underfloor heating. Because of this, you shouldn’t use underfloor heating under the vinyl in places that need a lot of heat, like conservatories.

Layer glued wood

The best flooring for underfloor heating. It works well with the changing temperature of the soil and adjusts to the changing amount of water in the soil.

Layer-glued wood is a great choice for a wooden floor that will be heated from below. This wood can handle temperature changes in the soil well without cracking.

Solid hardwood

is sensitive to changes in humidity and temperature, which can cause cracking, warping, and warping.

When using this floor covering with underfloor heating, you must ensure it works well and gives off enough heat. Always ask the manufacturer if the material can be used with your heating system.


It can be used with underfloor heating, but you need to pay attention to the floor panels’ thickness to ensure it works well.

Parquet floor

You can choose between solid wood and plywood. Most of these types of floor coverings can be used with floor heating.


It’s like engineered plywood because it’s a good heat conductor, so it works well with underfloor heating.

Underfloor heating under solid wood floors

Underfloor heating has many benefits in the living area, which is why builders and residents like it. Use under wooden floorboards and parquet is also fine, as long as you keep these things in mind when choosing a system and putting it down.

How do you heat the floor from below? Radiant heat is not at all the same as heating that comes from the floor. This is especially true when water-carrying systems are installed under solid wood floors.

Even though this area can be heated very well now, there are some things to remember when working with wood.

Because a plank is still a natural product, whether treated or not, the specialist merchant must also consider many different values and specific properties of the materials.

For wooden floorboards to be used, the subfloor must be dry. This is also true for floors that don’t have heating under them.

In this case, the remaining moisture must be considered, especially if a wet screed was used. The amount of remaining moisture is measured in CM% by the so-called calcium carbide method (CM measurement).

Different types of screed have different levels of residual moisture that show when they are ready to be covered.