How Building Materials Affect Cellular Signal Strength

How Building Materials Affect Cellular Signal Strength

While many of us may not think about it, many things block the cellular signal. Various weather patterns, locations, and terrain can all lead to a weak signal. But the composition of your building may also be the culprit for your dropped calls. Commonly used building materials like brick, glass, wood, metal, and drywall can all impair your signal. Read all about how building materials affect cellular signal strength, both at home and in the office.

Measuring Cellular Signal

Decibels-milliwatts measure cellular signal strength, and the further the number gets from -50, the weaker the signal is. This is because every building material has a different decibel (dB) reading which changes your dBm number. Materials that weaken your signal by -12 dB reduce more signal than those that only reduce it by -2 dB.

To understand how much a material impairs your signal, you’ll have to take your dBm reading—found in your settings—and subtract the dB from it. In other words, if you have an ideal signal of -50 dBm, you’d have to subtract the material’s dB reading. So, you could go from -50 dBm to -100 dBm depending on the building materials. As you inch closer to -120 dBm, you get closer to a dead zone.

What Materials Affect Signal Strength

Some building materials affect your cellular signal strength differently than others, as they cause a stronger signal loss. By understanding this, you can begin detecting the reason for your dropped calls, and then find the best solution! Note that this material alone causes a signal loss, and as you layer the materials, the loss becomes greater.

Drywall and Insulation

Both drywall and insulation are materials used in all building construction, but they also weaken your cellular signal. Typically, both drywall and insulation cause a -2 dB signal loss. So, you could have a loss of -4 dB if your building has both drywall and insulation.


Glass is another common material known for weakening your signal strength, and different types of glass may affect it more than others. Although clear glass isn’t as bad as its tinted or low-energy variants, it refracts or redirects your signal. As a result of this refraction, your signal could face up to a -4 dB loss.

Tinted and Low-Energy Glass

Tinted and low-energy glass help a building be more energy-efficient and increase privacy. But one drawback of using these materials is the negative impact they have on your call quality. Both materials can reduce your signal by -24 to -40 dB, and that’s without taking other building materials into account!


Wood is the general term for this commonly used material. We see it everywhere, from building interior to flooring, doors, and furniture. However, different wood causes different signal loss, and both solid wood and plywood will weaken your signal. As the wood becomes thicker, the cellular signal becomes weaker.


Since plywood is thinner, the loss isn’t typically as significant. Usually, you can expect a signal loss of -4 dB to -6 dB if it’s one of the materials between you and the nearest cellular tower. But remember—you have to add this to the signal loss of other materials. One problem with plywood is that if it gets wet for any reason, then that -4 dB to -6 dB jumps to a -20 dB. Why? Because plywood absorbs water, which further blocks your signal.

Solid Wood

Any thick wood blocks the cellular signal, thus weakening overall signal strength. And while thick wood may be great when you’re constructing something, it’s also going to weaken your signal by -5 dB to -12 dB. Likewise, oak, mahogany, and maple look great, but these and other types of wood will also block and absorb your signal.


Just like glass, plaster shouldn’t affect signal strength in theory. Although it’s not clear like glass, plaster is still very thin. So, how could it cause a -8 dB to -16 dB loss? Well, to make plaster, you need gypsum and lime cement, all of which weaken cellular signal.