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What Material Can Block EMF?

Metals block electromagnetic radiation by reflecting it. 

Metals like aluminum and silver are smooth with no surface to penetrate the metal and instead reflect the radiation from their surface.

Make sure you have read our articles on What Does EMF Radiation Mean? to have a full understanding of EMFs as we discuss what materials can block EMF. 

How is EMF Radiation Created?

This is a summary of what EMFs are. For a full article, read about EMF (theoretical).

EMF stands for electromagnetic radiation. 

Accelerating charged particles produce changing electric and magnetic fields. 

Electric and Magnetic Field waves

This interplay between fields creates energy in the form of electromagnetic waves that move through free space. 

This released energy emission is radiation. 

When radiation moves through the air it travels in waves. Higher frequency waves emit a lot of energy and have a shorter wavelength. 

Lower frequency waves are longer and emit low energy. All these waves are placed on a spectrum – the electromagnetic spectrum. 

They are ordered from low to high energy waves. 

If a emf meter is showing high radiation then you can easily block emf in house using some techniques.

Ionizing Vs. Non-Ionizing Radiation

The high energy waves are ionizing waves, which are the most powerful. Gamma rays, nuclear energy, x-rays and even some UV rays are ionizing. 

These can instantly cause damage to the body by shattering electrons and shattering the molecules in our bodies. 

Non-ionizing radiation is weaker but it can still alter cells on a biological level after a long period of exposure. 

These waves include infrared, microwaves, radio waves (RF) and extremely low frequency waves (ELF). Sources of RF and ELF radiation include cell phones, Wifi, Bluetooth and even appliances like hairdryers. 

Extremely Low Frequency (ELF) Radiation and Radiofrequency (RF) Radiation

ELF radiation comes from currents flowing in an electronic device. It is the lowest frequency of radiation but all devices emit it. Anything that gets power from an outlet or a battery. 

Since most sources are used briefly and from a safe distance they aren’t as damaging in the long run. 

Smart devices like cell phones, smart watches, laptops, tablets and wireless Bluetooth headphones emit both ELF and RF radiation. 

RF radiation is emitted when the smart device connects to Wifi, uses the cellular network, 5G, uses Bluetooth, etc. 

RF radiation travels. Bluetooth signals travel up to 30 feet. 

Wifi travels up to hundreds of feet. 

Cell phone signals travel several miles. 

The closer you are to the source of radiation the more you are receiving. 

Does foil block radiation?

Aluminum foil does block or attenuate some types of radiation. 

Aluminum foil will not block high energy gamma rays or x-rays. A thick layer of lead is required to block gamma and x-ray radiation.

Aluminum foil can block radiofrequency (RF) radiation like those from Wifi or a cell phone. 

EMF of a battery can be reduced in this way also.

What is the best metal to block EMF?

Some common materials used for electromagnetic shielding include sheet metal, metal screen, and metal foam. 

These materials can be effective in reflecting or absorbing electromagnetic radiation, depending on the physical properties of the metal. 

For example, electrically dominant waves are typically reflected by more conductive metals like copper, silver, and brass, while magnetically dominant waves are more effectively absorbed/suppressed by less conductive metals such as steel or stainless steel. 

Any holes or gaps in the shield or mesh must be significantly smaller than the wavelength of the radiation that is being kept out, or the enclosure will not effectively approximate an unbroken conducting surface.

Can concrete block EMF?

No concrete does not block EMF. Concrete can reduce or attenuate EMF radiation though.

The thicker the concrete the more it reduces EMFs (6). 

Do magnets affect radiation?

Electromagnetic waves will pass through magnets without being affected. 

Magnetic fields as they relate to radiation only affect polarity, not electromagnetic waves or radiation. 

Do electrical outlets emit radiation?

Electrical outlets emit extremely low frequency (ELF) radiation.

ELF radiation comes from the flow of currents, including electrical outlets.

Does silk block radiation?

Silk does not block radiation but it will reduce or attenuate ultraviolet (UV) radiation that causes sunburns on skin.

Silk will not block RF or ELF radiation. 

Do breaker boxes emit radiation?

Electrical outlets emit extremely low frequency (ELF) radiation.

ELF radiation comes from the flow of currents, including breaker boxes.

What is EMF fabric made of?

EMF fabric is made of metals that block EMF radiation. 

Most use a Faraday cage. A Faraday cage is an enclosure formed by conductive material or by a mesh of conductive material. This fabric from Amazon is made with metals like copper and nickel.

How can you prevent electromagnetic waves?

There are a few ways that you can block EMF in your house such as:

1. Use an EMF Shield

2. Turn Off Electronics

3. Move Electronics Away from Your Bed

4. Limit Time Spent Near Electronics

Further Reading:


  1. University of Tennessee Knoxville – The Production of EM waves
  2. World Health Organization – Radiation: Electromagnetic Fields
  3. Occupational Safety and Health Administration – Ionizing Radiation
  4. Physicians for Safe Technology – Behavior, Memory and Learning:
  5. Electromagnetic shielding – Wikipedia –
  6. Stone, W. (1997), Electromagnetic Signal Attenuation in Construction Materials, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online],