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Written by Sadia Jahangir
3rd Dec, 2022

What can interfere with cell phone signal?

It is not a secret. Building materials are often the main cause of poor cell phone signal in the home.

4G, LTE, and 5G signals are radio frequency waves. Like all radio waves (cellular, Wi-Fi, AM/FM radio, satellite, etc.), obstructions can weaken and degrade cellular signals. This is especially true for the high frequencies of 5G. Today we are looking at the main building materials that block RF signals and to what extent.


First, a quick overview of how to measure cell phone signal strength

Radiofrequency waves are the medium by which cellular devices, small cells, and cell towers communicate with one another. Bars represent the amount of signal you receive from nearby small cells or cell towers.However, your phone’s number of bars does not accurately reflect the strength of your cell signal.Bars differ between carriers and devices.

How subjective, you may inquire?

Two bars on AT&T could be three on T-Mobile or four on Verizon, despite receiving the same signal and operating at the same speed.The number of 1, 2, 3, 4, or full bars on your service is decided by your carriers.

Measuring your signal strength in decibels-milliwatts (dBm) is the most accurate method.A precise power level expressed in decibels per milliwatt is known as dBm.The signal strength can be anywhere from -120 dBm (dead zone) to -50 dBm (great signal).Your signal quality improves the closer you get to -50 dBm.

The measurement of signal strength in decibels (dB) is known as gain or loss.The logarithmic unit dB is used to measure the ratio of two power levels.We won’t go into great detail about dB; all you need to know is that every 3 dB means twice as much power is gained or lost.

So, what relationship does this have to building materials?

Building materials, on the other hand, reduce the signal trying to enter your home or workplace by dB.A dead zone forms as you get closer to -120 dBm with more loss.

Last but not least, a few words about 5G. Compared to 4G and LTE, 5G signals broadcast at a longer wavelength.As a result, assume an even worse impact on all 5G signals for each number in the following section.

Building Materials that block your Cell Phone Signal

11. Nature (from -3 to -20 dB)

Okay, it’s not building material, but it’s still a good place to start. People frequently ask: Are cell phone signals hindered by trees? The answer is emphatically “yes.” Your 4G, LTE, and 5G signals are affected by trees, hills, mountains, and even the weather. How much more?

  • Rain -3 to -5 dB
  • Foliage -7 to -20 dB

This chart is for LTE; signals for 5G are more affected. Because it reflects and absorbs cell signals, foliage, particularly pine, poses a significant threat. and winter provides a better signal for the majority of homes and offices. Fewer leaves mean fewer obstacles from the air. Although rain has less of an impact on cell phone reception, when combined with foliage or in areas with poor signal, it can have a significant impact.

10. Sheetrock/drywall (-2 dB)

Your inside walls and roofs are no doubt produced using drywall. Even though they are among the signal-blocking agents of lower quality, they can damage your outside signal if it is already weak.

9. Insulation made of glass (-2 dB)

Additionally, cell signals are blocked by fiberglass insulation in the attic or walls. LTE suffers a loss of -4 dB when paired with drywall. This indicates that by the time it enters your home, your outside signal is reduced by more than 50%.

8. Clear Glass (-4 dB)

Most people instinctively move closer to a window when cell reception is poor in a home or office. However, despite the fact that it may not appear so, windows reflect and refract cellular signals. LTE has an average signal loss of about -4 db. Cell signals are further impacted by windows with double or triple panes. Therefore, if standing by a window that is closed does not improve the quality of your signal, open it as much as you can for the best results.

7. Plywood (-4 to -6 dB)

Another type of sheet material, plywood, has a signal reduction of up to -6 dB for 4G and LTE networks and about -9 dB for 5G networks. The plywood will have a greater impact on cell phone signal strength the thicker it is. If the plywood is not water-resistant, it will behave like a sponge and weaken the signal by up to -20 dB if it gets wet.

6. Solid Wood (-5 to -12 dB)

Even though they are nice, hardwood floors, walls, doors, and furniture kill cell signals. Any kind of wood, including maple, beech, ash, oak, mahogany, and others –can both absorb and block signals from cells. The signal gets worse the thicker the wood gets.

5. Plaster (-8 to -16 dB)

Plaster is a mixture of lime or gypsum, sand or cement, and water, and hardens when dry. It is commonly used in offices and homes. It is used to cover internal walls and ceilings, protect them, and decorate them. Who would have thought that plaster could reduce signal strength by as much as -16 dB?

4. Stone and Brick (from -8 to -28 dB)

Stone and brick are excellent building materials for design and aesthetics. They not only stop the big bad wolf from blowing down your house, but they also significantly weaken cellular signals by up to -28 dB, so you might get better reception in rooms that don’t have brick or stone walls.

3. Concrete & Cement: 6 inches (-10 to -20 dB)

Nothing unexpected here. Concrete is used to build most modern structures. Concrete and cement’s industrial strength is used by many architects to build sturdy structures. Because of this, it can be difficult to get a working signal inside many urban areas. For every six inches of concrete and cement, signal loss varies from -10 dB to -20 db.

3. Concrete & Cement: 6 inches (-10 to -20 dB)

Nothing unexpected here. Concrete is used to build most modern structures. Concrete and cement’s industrial strength is used by many architects to build sturdy structures. Because of this, it can be difficult to get a working signal inside many urban areas. For every six inches of concrete and cement, signal loss varies from -10 dB to -20 db.

2. Low-E Glass with tinting (-24 to -40 dB)

Tinted Low-E glass is used in newer buildings to keep heat out and reduce glare. Since they’re “just” glass, you’d think they’d have the same effect on cell signal as clear glass, right? Tragically, that is not the situation. They frequently contain metal additives and reflect signals better. Cell signal is reduced eight to ten times more by tinted and Low-E glass than by clear glass due to this.

1.Metal (-32 to -50 dB)

Metal is the most effective material for blocking cellular activity in American buildings. Lead, aluminum, brass, copper, steel, iron, aluminum foil, and others reflect and absorb cell frequency waves. The average signal loss in your building is -50 dB, which is high enough to make it a dead zone.

How Much Blocks Cell Signaling in Building Materials

Your cellular signal is affected by almost anything. A typical house with drywall, plaster, glass, and wood can lose up to -30 dB or more when the whole picture is taken into consideration. That amounts to about two to four bars less in “bar speak.” Remember: These figures pertain to LTE and are even more significant for 5G.

Building Material

dB Loss


-3 to -20



Fiberglass Insulation


Clear Glass



-4 to -6

Solid wood

-5 to -12


-8 to -16

Brick & Stone

-8 to -28

Concrete & cement (6 inches)

-10 to -20

Tinted & Low-E Glass

-24 to -40


-32 to -50

An easy-to-use infographic depicts everything we’ve talked about.

Can aluminum foil block the radiation from cell phones?

Because it is made of metal, aluminum foil can prevent cellular signals from entering your home. It is utilized by many to construct a Faraday cage. It may take several layers of aluminum foil to completely block radio waves, depending on the type and strength of your cellular signal.

Is concrete the most effective material for preventing wireless signals?

Metal has 6 inches of concrete beat, placing it in the top three worst materials for blocking signals. Loss Concrete can become the worst material for blocking wireless signals if the thickness is doubled or tripled.

  • Metal -35 to -50 dB
  • Loss 6″ Concrete -10 to -20 dB

Will cell service be affected by metal roofs?

Unfortunately, yes, a lot. Reliable indoor reception is difficult for those with metal walls and roofs.RF signals are distorted even when there is metal in the home. If this is a problem for you, check out our guide on how to improve cell signal inside a metal building.

Which metal prevents cell signaling?

Basically, every metal. Lead, brass, aluminum foil, tin, copper, steel, iron, and other materials there will variation in the extent to which each type of metal affects cell signal.

Does carbon fiber hinder cell communication?

Carbon fiber is a material made of bonded carbon atoms that is strong, thin, and lightweight. It’s used to make things like phone cases, building materials, car parts, and more. Carbon fiber can reduce radio frequency waves’ energy because it is conductive. Consequently, reducing or eliminating all 4G, LTE, and 5G signals.

Do trees hinder cell phone reception?

Absolutely. Radio waves are reflected and absorbed by the water tress hold, thick trunks, thick branches, and leaves. Cell signal is most affected by pine trees.

Is Rain Weakening a Sign?

Yes. Cellular signals are reflected, refracted, and absorbed by rain. A loss of -3 to -5 dB is normal, and the signal gets weaker the more rain there is.

How do you disable cell phone signals?

You can reduce or block cellular signals in the following ways:

  • Install a metal roof
  • Install furniture made of wood
  • Upgrade to low-E windows
  • Plant pine trees
  • Use any of the other materials mentioned in this article to line your home.

How can building materials be bypassed to boost cell signal?

A cell signal booster for homes and businesses can be of assistance if you are sick and tired of building materials preventing you from receiving dependable calls and data.

Your existing outside signal is amplified and broadcast inside by cellular boosters. They accomplish this by employing an amplifier, an indoor antenna, and an outdoor antenna. Low-loss coaxial cable connects all components. This permits the unit to sidestep all sign-obstructing material.

The most well-known manufacturer of cellular signal boosters is Bftsync. For home, office, or vehicle use, cell phone boosters can amplify 5G, 4G, LTE, and other networks for any phone with any carrier. They work best with an antenna pointed toward the nearest cell tower.

We truly detest dropped calls and poor coverage, so one satisfied customer at a time, we want to rid the world of spotty signals:

  • Contact our US-based customer support at for a complimentary consultation or call us at 1-281-616-5786 to ask us anything.
  • Free delivery.
  • Better signal or you’ll get your money back in 90 days.
  • We offer lifetime technical support and a two-year warranty on all products because we want everyone to be happy.

If you have any questions, we are happy to assist.

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