Which Building Materials Block WiFi And Cellular Signals?

Are you aware that there are different types of building materials that can block out Wi-Fi and cell phone signals? In this article, we will be discussing exactly what these materials are. If you are having reception issues with your cell phone, then you might discover that you are somewhat frustrated with trying to figure out what is causing your weak signal. Your cell phone is working in certain areas outside of your house, but inside your home, you are getting no or little signal. Obviously, there is something inside your house that is preventing reception, but what exactly is causing it? And can a signal booster help you out?

Note that although we will be mainly discussing mobile signal strength attenuation here, there is a similar attenuation for wifi signal strength. The 802.11 standard offers several separate radio frequency ranges for using in Wi-Fi communications: 60 GHz bands, 5.9 GHz, 5 GHz, 4.9 GHz, 3.6 GHz, 2.4 GHz, and 900 MHz. Each separate range is divided into several channels. So we won't be going into a lot of details so that we don't get distracted or sidetrack with all of the wifi and mobile channels and frequencies. However, you can get an overall idea from the following list on how much the signals will be attenuated by which materials and products.

Clear Glass

Clear Glass

When it comes to clear glass fixtures, like windows, there is a misconception, in terms of where is the best place for getting access to a good signal. Although this clear area is perfect for allowing light in, windows can actually reflect a signal away from the home or bounce it around. That is particularly true for double insulated windows. Newer houses have triple-pane windows that reflect signals to an even greater extent. The ones that deflect the most are the newest low emissions (Low-E) windows which keep out the elements so that you remain cool or warm depending on what the weather is like outside. However, if you are trying to stand close to a window, for the most impact, open the window. The blockage on a window can be as much as -4db.

Insulation and Sheetrock

For cell phone signals, sheetrock is among the lower blocking agents. However, it may cause a signal to be completely blocked if it is weak already. One thing to keep in mind is that 5G, 4G, and 3G signals usually are the same thing as a radio signal. Therefore your signal can fluctuate by -2db. Closed rooms, which means whose that do not belong to an open floor plan, are a lot more susceptible to signals on cell phones to be disrupted compared to rooms made out of sheetrock that belong to an open layout.

Fiberglass insulation is porous, however, this insulation in the attic and in walls can slightly disrupt cell phone signals if the insulation is thick enough. Some insulation products have a foil-faced design that helps to keep unwanted elements out. However, this foil facing contained in certain insulation products like fiberglass batts or foam board may block out radio frequency signals. The interior walls also are made out of denser materials that can reduce reception by an additional -2db. In this way, insulation and sheetrock can potentially reduce your cell phone reception before entering your house.

Solid Wood And Plywood

Plywood makes up most of the framework and structure of many residential houses and reduces 4G and 3G networks by as much as -6db. On a 5G network, there is an even higher reduction at -9dB. That number fluctuates somewhat since there are various thicknesses of plywood and various ways that plywood is compressed. The loss in cell phone reception also can be increased if the plywood gets wet or damp with numbers going down as low as -20db. However, if plywood on your home is wet, then there are bigger problems for you to be concerned with.

Solid wood, like the kind used in flooring for a home builds on the plywood's blocked signal. Although the finishing on decking, floors, doors, etc might give a nice natural appearance, they block cell phone signals. All types of woods slow a signal down. The thicker that wood is, the more it has a tendency to disrupt the strength of your cell phone signal. Softer woods, like pine, might not decrease the signal's strength a lot, but you may still experience loos of -5 to -12db.



Although brick is very sturdy when it comes to standing up against the elements, it is one of the main materials that blocks a signal. First of all, there is the thickness of brick that slows down the signal. Then there is the mortar that is in between the bricks that doesn't allow a signal. Also, brick usually has extra materials on the inside so that other components can be added such as shelves, sheetrock, and electronics. The thickness of a wall in combination with the density of the brick can block up to -28db scale.


Metal is the top building material that disrupts cell phone signals. Metal roofs, along with interior metal and metal studs slow the signal down. Although metal is durable against elements, looks good on a building and helps to route electricity away from the wall, it may route a signal away from your house as well. A majority of houses with metal roofs will discover that even when they are living in a certain area with strong exterior signals, interior signal strength may be non-existent or weak. Ratings can go as low as -32 to -50db, which basically makes your house a dead zone.


So there are many things to look out for when you trying o judge what is harming your Wi-Fi signal. However there is always a solution! Check out our mobile signals boosters so that you can always have amazing internet access 24/7!