Does LoRa Mesh Work Through Walls? How to Test Buildings and Indoor Routes

Prepared by the ChatField Editorial Team. Evidence reviewed August 18, 2026.

“Does LoRa work through walls?” sounds like a yes-or-no question, but a useful answer requires the building, product and communication task. A timber house, concrete warehouse, underground structure and high-rise core create different radio paths.

Semtech describes LoRa technology as suitable for long-range and challenging coverage applications. That capability does not create a universal number of walls, floors or meters. NIST building measurements show that material and structure can produce large and variable signal losses.

This guide explains how to test a LoRa mesh communicator in buildings. It does not promise indoor performance for a future ChatField product.

Short answer

LoRa signals can pass through some building materials and can also be weakened, reflected or blocked. Performance depends on frequency, transmit power, antenna, radio settings, building material, wall thickness, metal, elevation, device placement and interference.

Do not accept “works through ten walls” without the exact building, route, device configuration, task and repeated results. Test the route where the team will actually work.

Why walls do not have one radio value

Drywall, glass, wood, brick, reinforced concrete, metal panels and energy-efficient coated glass interact with radio signals differently. Moisture, wiring, pipes, shelving, vehicles and machinery add more variation.

NIST research describes strong attenuation and scattering caused by building materials and structures. Other NIST measurements show wide penetration-loss ranges even among common materials. Those studies are general radio-propagation evidence, not J25 or LoRa product tests.

The ChatField technology page identifies the communication layers that a buyer should isolate during testing.

Frequency is only one factor

Lower radio frequencies are often associated with different propagation behavior than higher frequencies, but frequency alone does not predict a finished product's result. Antenna efficiency, bandwidth, data rate, output power and receiver design matter.

A LoRa chip datasheet or regional frequency label cannot replace finished-device testing. Compare the complete hardware and approved configuration.

Do not transfer a 700 MHz building study directly into a 900 MHz product claim; use it to understand why measured environments matter.

Metal creates special problems

Metal walls, elevator shafts, reinforced concrete, racking, vehicles and equipment enclosures can shield, reflect or redirect signals. A device inside a metal vehicle or cabinet may perform differently from the same device worn in open air.

Test doors open and closed, equipment operating and idle, and the actual carrying position. Record whether the antenna is covered by the body, bag or structure.

Do not place an intermediate device inside a sealed metal enclosure unless the product and installation are designed for it.

Floor-to-floor paths differ from hallway paths

A long corridor may provide a useful path while a short vertical route crosses reinforced floors, mechanical systems or a central core. Stairwells, windows and open atriums can change the result.

Map each floor and identify vertical shafts, fire doors and exterior routes. Test same-floor, adjacent-floor and multi-floor paths separately.

The ChatField signal-path explanation helps record the sending terminal, any participating node and receiving terminal at each checkpoint.

The phone link can fail before the LoRa link

In a phone-paired system, the phone-to-terminal Bluetooth connection and the terminal-to-terminal LoRa path are separate. A user may blame the building when the actual issue is phone pairing, app background behavior or device placement.

Confirm Bluetooth connection at both endpoints before interpreting the LoRa result. Keep the phone near its paired terminal according to the product instructions.

The current J25 product page describes this phone-paired architecture for J25 only.

Define the communication task

A short text, PTT exchange, location update or other supported function may produce different user experiences. Test each supported mode separately and record success, delay, acknowledgement and recovery.

Do not call a route successful merely because the app opened or a device icon appeared. Define what the recipient must receive and how the sender knows the task is complete.

If a function is not documented for the tested model, remove it from the test.

Build a floor-plan test

Mark the command point, entrances, stairwells, elevators, work zones, storage areas, mechanical rooms, basements and exterior assembly points. Assign checkpoint codes that testers can report consistently.

Start with two devices at close range. Then move one endpoint through planned checkpoints while keeping the other position stable. Repeat in both directions.

Record walls, floors, doors, elevation, device height, carrying method and major obstructions at every checkpoint.

Repeat at different operating times

A quiet empty building can differ from a full shift with people, vehicles, machinery and other wireless systems. Repeat critical routes under representative conditions where safe and authorized.

Record time, occupancy and notable equipment state. Do not claim interference as the cause of a failure without suitable evidence; label it as an observation or hypothesis.

Preserve stable, marginal and failed results instead of publishing only the best attempt.

Test placement before adding devices

Raise or move an endpoint within the normal carrying limits and observe whether the result changes. A small placement change can alter the radio path around obstacles.

Do not optimize the test with unrealistic roof or window positions if workers will carry the product at belt or pack height. Procurement evidence should reflect the actual workflow.

Use the off-grid communication guide to keep range statements attached to terrain and placement.

Evaluate intermediate nodes carefully

If the tested product supports participating intermediate devices, try documented positions such as a stairwell landing, corridor intersection or approved high point. Record the device role, power, security and responsible person.

A result that improves with an intermediate position applies to that tested layout. It does not prove a universal relay count, automatic route or whole-building guarantee.

Power the intermediate device off during a controlled exercise and document recovery.

Plan power and access

A fixed intermediate position needs charging, inspection, environmental protection and authorization. A user-carried node can move away from the planned path.

Identify who checks the device, how often and what happens during a power failure. Do not place equipment where it obstructs egress or violates site rules.

Building test checklist

• Exact terminal, phone, app and firmware versions
• Regional radio configuration and approved antenna
• Floor plan with coded checkpoints
• Wall, floor and major material descriptions
• Endpoint height, orientation and carrying method
• Bluetooth connection verified separately
• Each supported communication mode tested separately
• Repeated attempts in both directions
• Occupied and representative operating conditions
• Stable, marginal and failed checkpoints
• Intermediate positions where the product supports them
• Power-loss and route-recovery exercise
• External backup and emergency communication plan

Questions for a crowdfunding campaign

• Which indoor environments were tested?
• What materials and number of floors were involved?
• Where were the devices and antennas carried?
• Which product function was used for the result?
• How many repeated attempts succeeded?
• Were intermediate devices involved?
• Which regional hardware and firmware were tested?
• Does the evidence include failed or marginal checkpoints?
• What happens when a phone, terminal or intermediate device loses power?
• Which indoor claims remain development targets?

ChatField building-test boundary

The current J25 specifications and public pages provide model-specific information, but they do not guarantee performance inside every building. Use the ChatField contact page to discuss a representative site evaluation.

No J25 indoor result, relay behavior, frequency configuration or FCC evidence should be transferred to an unconfirmed future crowdfunding model.

Sources reviewed

• NIST: Attenuation of Radio Wave Signals in Large Buildings
• NIST: Building Penetration Loss measurements
• NIST: Building and urban propagation measurement environments
• Semtech: LoRa wireless RF technology overview

NIST and Semtech do not endorse ChatField or its products. NIST measurements are cited as general propagation evidence and are not presented as LoRa or ChatField performance tests.