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taylorvich [soylentnews.org] writes:

https://techxplore.com/news/2024-12-nondestructive-microwave-radar-moisture-walls.html [techxplore.com]

For homeowners, moisture buildup can cause the biggest headaches. Mold grows on drywall and wood-based materials, creeping along walls, floors and ceilings. Building materials begin to erode and rot. As insulation becomes damaged, the home's energy-efficiency decreases. Even human health suffers, as moisture also leads to air-quality issues.

The key to preventing extensive moisture damage is discovering it early, when it can be easily fixed.

Researchers at the Department of Energy's Oak Ridge National Laboratory are using microwave radar reflection to nondestructively detect and measure the moisture content of materials within walls without removing drywall or cladding. This also expedites moisture identification and enables mold growth to be treated in the early stages.

The research team's study results were published in IEEE Xplore and presented during the IEEE Radar Conference 2024 in Denver.

"We know microwave radar shows great promise for this, because it's well known that it can measure the moisture in wood samples," ORNL's Philip Boudreaux said. "But can it measure moisture in wood that is inside a wall to detect high-moisture issues before they become a big problem? That's the challenge."

The envelope of a building consists of exterior walls, the roof and foundation, all of which join to prevent moisture transmission. But the envelope is itself prone to moisture issues caused by many factors: too much rain, ground dampness, air leaking through holes, and vapor diffusion when moisture moves from higher to lower concentrations through the envelope.

Most homes are made from wood-frame construction, and when wood is moist, it's the perfect environment for mold to grow. If a wall is damaged or designed incorrectly, water vapor that seeps through wood can make it damp. For this reason, Boudreaux said, wood was selected as the initial material to investigate the capabilities of microwave radar.

"You can detect water within wood with microwave energy that reflects off of the material using radar," Boudreaux said. "You can also measure moisture in more than one type of material within the wall."

As part of the electromagnetic spectrum, microwaves interact with materials in a similar way to visible light, but they penetrate further, creating reflections. Radar systems work by emitting signals like microwaves and then detecting the reflections of those microwaves. When used with walls, the microwave reflection pulse characteristics are based on the moisture in the material.

Walls are made up of layers of materials, and each layer may have different amounts of moisture. However, by measuring the length of time taken for the microwaves to return to the sensor, the distance to each material in the wall can be calculated, and this can be used to map out and measure the moisture within the layers.

Original Submission