Wall-Material Attenuation Cheat Sheet
July 6, 2026 · 2 min read · SiteOps Command
The single biggest variable in a predictive Wi-Fi heatmap is also the one most often guessed: what the walls are made of. Distance matters, but material matters more — and getting it wrong is how a heatmap ends up confidently describing a building that does not exist.
Why material beats geometry
Two rooms the same size, one framed in drywall and one poured in concrete, are different buildings to a radio. The signal that sails through the first is stopped cold by the second. That is why the material, not the floor area, is the number to get right. The physics behind it is ITU-R P.2040; the deeper story is in the physics of an honest heatmap.
The cheat sheet
Representative and illustrative — actual loss varies with frequency, thickness, and construction, and the real physics comes from ITU-R P.2040 material permittivity. Use it to know where to look, not as a spec.
| Material | Relative Wi-Fi loss | Notes |
|---|---|---|
| Open air | negligible | the baseline |
| Drywall / partition | low | but it stacks over many walls |
| Interior glass | low (plain); higher if coated | radio passes; glass is not a wall |
| Solid wood door | moderate | varies with how solid it is |
| Brick / block | high | common in older building cores |
| Concrete | very high | floors and shear walls |
| Metal / racking | severe | reflects and blocks; the warehouse problem |
The traps
The losses that surprise people are the ones that hide. Many drywall partitions in a row add up to a concrete-equivalent wall. Metal studs inside ordinary drywall raise its loss. Mirrors and metal-backed insulation reflect. And warehouse racking is effectively a metal wall that moves with the inventory — it gets its own post, why racking wrecks warehouse Wi-Fi.
Use it as a sanity check, not a spec
A cheat sheet ranks materials; a real design computes the loss per wall from the material, the frequency, and the geometry, and takes the conservative of the discrete and statistical models. The table tells you where to look. The physics tells you the number.
A heatmap that assumes every wall is drywall is a heatmap for a building that does not exist. See the coverage physics page, the Ekahau comparison, the MSP workflow, or book a demo on your own floor plan.
Frequently asked
- How much does drywall attenuate Wi-Fi?
- Not much per wall, but it adds up: several drywall partitions in a row can total the loss of a single concrete wall. The exact figure depends on frequency and construction; material and count matter more than distance.
- What building material blocks Wi-Fi the most?
- Metal and reinforced concrete are the worst — metal reflects and blocks, concrete absorbs heavily. Glass and drywall pass far more signal, and warehouse racking behaves like a metal wall.
- Can you calculate Wi-Fi loss from a material cheat sheet?
- A cheat sheet ranks materials for a sanity check. A real predictive design computes loss per wall from the material (via ITU-R P.2040), the frequency, and the geometry, rather than a single lookup value.