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10 Materials that Can Block Mobile Phone Signals in the Building

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Nowadays, mobile communication is so developed that people can talk to anyone anywhere in the world with perfect sound quality and use high-speed Internet without the need for a cable connection. But all these benefits can disappear if the signal is lost. You have probably noticed that when you enter a building, the signal strength on your smartphone deteriorates. That's because the architects did not take into account that some materials block the mobile signal.

Many building materials block the mobile network, but when used separately, it won't cause that much trouble. For example, a shingle roof won't deteriorate the signal strength. However, if several structures are made from these materials in one building, then signal issues can be critical. Below, we will look at what blocks mobile phone signals and discuss UCtel's methods to bypass all signal-blocking material.

What Can Block Mobile Phone Signals?

The mobile signal is measured in dBm (decibel milliwatts). Typically, devices that support mobile communications operate at frequencies between -50 dBm and -120 dBm. If your mobile phone shows a full signal scale (-50 dBm) outside, and it immediately worsens inside the building (-90 dBm and lower), the chances are that the structure itself is jamming it. Let's look closer at the list of natural materials that block mobile phone signals in your home or office.  

Wire mesh

Building materials containing wire mesh or metal mesh, such as some types of reinforced concrete or metal screens, can weaken mobile signals or even create a dead zone. Even though modern 4G and 5G technologies are less affected by this obstruction, it still can be quite a problem in some remote areas.

Ceramic or porcelain tiles

Generally speaking, ceramic or porcelain tiles won't have any effect on signal strength. However, if they have some metallic elements or coatings, they become a material that can interfere with mobile phone signals. It won't block your connection entirely, but combined with other materials can degrade the quality of your calls up to 5 dB.


Although large mirrors are not commonly used as building materials, they can reflect and scatter mobile signals, which can cause signal problems in certain areas. For example, a large full-wall mirror in a gym is a material that reduces mobile signal.

Low-E glass

Low-E glass, or low-emissivity glass, is a type of green building material commonly used in office and residential buildings. The purpose of Low-E glass is to reduce the amount of heat that makes its way into a building through glass windows or doors, without minimising the amount of light. As a result, people inside the building can enjoy the coolness and save on energy bills. 

Although Low-E glass has become quite popular because of its eco-friendliness, it is one of the materials that block a mobile phone signal. Low-E glass subtracts 40dB from your mobile phone signal, which can be quite damaging to the quality of the calls. 

Fibreglass insulation 

Fibreglass insulation is a go-to choice for many homeowners as it is cheap, effective, and easy to install. Not only does it protect you from the heat in the summer and cold in the winter, but fibreglass is also known to be moisture and fire-resistant, keeping your belongings safe even in case of a flood or fire. Additionally, fibreglass is highly durable, eco-friendly, and will soundproof the premises. 

No wonder fibreglass insulation is a popular choice to insulate and soundproof a house. Unfortunately, it comes at a price: it can block mobile signals. Even though fibreglass is a lightweight building material, it is often applied in thick layers to ensure efficiency. Moreover, foil is often used as insulation material to enhance the effect even further. As a result, this mobile phone signal-blocking material can deteriorate your phone reception by 2dB.  


When it comes to wood, it is important to note what material blocks mobile phone signals the most. For example, wood materials like beech, ash, maple, oak, or mahogany can substantially affect the signal quality up to 12 dB. On the other hand, Plywood reduces the reception by 6 to 9 dB, which is also quite damaging but to a lesser degree. 

Additionally, natural woods near your house can be accountable for your poor mobile signal. Depending on the forest type and density, your connection might experience a loss range from 5 to 12 dB. 


If you are experiencing poor connection at home and can’t figure out which material disrupts your signal, there is a huge possibility that you have brick walls. As a tenant, you might not even know what is behind the layer of paint or paper wall. Brick walls are quite popular in residential construction, as they keep you warm in the winter and cold in the summer. It is also an affordable building material, but it can block your mobile and Wi-Fi signals. 

Besides brick, we can also mention kitchen or bathroom tiles as well as stone. Depending on the thickness and the density of the brick construction, you may be losing somewhere from 8 to 28 dB. 


Concrete is not one of the materials that block mobile signals inside your office or kitchen, as it is commonly used as a building foundation and material for roads and bridges. Due to its thickness and density, the reason for using concrete is its ability to withstand enormous weights. 

You have certainly faced a reception issue or mobile signal blocking with concrete in a car park or basement. Although it realises its purpose and prevents buildings from falling down, it is one of the most significant mobile signal blockers out there. You will experience a 10 to 20dB deficit in the mobile signal quality. 


Although concrete and Low-E glass look like the answer to the question “What materials can block mobile phone signals the most?” wait until you find out the number for metal. Metal, being a building material that is used everywhere, in commercial buildings, offices, hospitals, shopping centres, residential homes, etc., is the most disruptive element. 

Whether it is aluminium, brass, copper, iron, or any other type of metal, it will cause the most damage to the call reception. When getting through a metal barrier, the mobile signal loses up to 50dB. 


Plasterboard is used in schools, hospitals, shopping malls, and residential homes to build partitions, wall linings, or ceilings. This material is at the bottom of our list, as it is the least harmful on our list of construction materials that disrupt a mobile signal. Although, if your signal is already weak, to begin with, even a small interference can cause issues with your calls. You can lose up to 2 dB if you are surrounded by plasterboard material. This is where the need to boost mobile signal in schools and similar buildings becomes critical, ensuring optimal connectivity even in spaces surrounded by plasterboard material.

How to Boost a Mobile Signal Bypass for Hard-to-Penetrate Construction Materials

With a mobile phone signal booster solution from CEL-FI, you can allow your mobile phone signal to bypass even hard-to-penetrate obstructions entirely using a network of indoor antenna systems. 

An external antenna can be set up wherever the mobile phone signal is strongest (usually on the roof). The mobile phone signal is boosted using an internal amplifier and fed indoors via a cable to an indoor antenna. This can be stretched out across your building’s interior, giving you reliable coverage so your family members and coworkers can get bars on their phones, wherever they are.

CEL-FI products are the perfect fit for your environmentally conscious building. You’ll be able to benefit from increased energy efficiency and green credentials while ensuring your staff can contact clients and loved ones, access mobile internet on 3G, 4G, and 5G, and stay connected.

Contact the team to discover how UCtel can improve your digital connectivity and communications. Get started

Discover UCtel’s Mobile Phone Signal Booster Solutions

UCtel is a company dedicated to improving the mobile signal in places where it is needed. UCtel installs mobile phone boosters in buildings that are built with materials that block required frequencies. 

For example, we recently improved the mobile signal of all four UK networks at the large Unipres plant in Sunderland. By installing the CEL-FI QUATRA 4000e system, we were able to increase the comfort of workplaces and increase the overall satisfaction of 1,300 employees. CEL-FI QUATRA is a hybrid Distributed Antenna System (DAS) solution that combines the benefits of passive and active DAS technologies to provide a mobile signal up to 1,000 times stronger than a pure analogue solution.

If you have signal problems at home or at work, you can always contact UCtel. Here you will get the best solution to your issue at the right price.

Final Thoughts

We are all surrounded by building materials blocking a mobile phone signal at work, at a shop, at home, etc. Now, you know what can block mobile phone signals in your office or home, and using a signal-boosting system, you can noticeably enhance your signal strength. If you want to discover more about what materials block mobile signals and affect phone reception, reach out to the experts at UCtel.  

Still have questions

Find answer below or contact us to ask more about UCtel

Which types of materials block mobile phone signals?

The most damaging phone-blocking materials are metal, concrete, and Low-E glass. However, brick, wood, wire mesh, mirrors, and fibreglass insulation can also significantly deteriorate the quality of your calls.

What can block mobile phone signals in buildings?

There are many reasons for experiencing poor phone signals such as unintentionally blocking the antenna with your hand, being in a crowded place, or being inside a building that is made of materials such as metal, wood, concrete, Low-E glass, fibreglass, and brick.

Can aluminium foil worsen a mobile phone signal?

Aluminium foil is a material that blocks mobile phone signals by up to 40 dB. Even compared to concrete and brick, aluminium and metal materials, in general, affect your signal the most.

Does metal negatively impact phone signals?

Metal is one of the building materials blocking mobile phone signals the most. If you are in a building with metal elements, the signal might go down by 40 dB.

Contact the team to discover how UCtel can improve your digital connectivity and communications.

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