Dec Scanner - Roofing Moisture Scanner to ASTM D7954

Non-Destructive Electrical Impedance Scanner

The Dec Scanner is ideal for carrying out moisture testing to ASTM D7954, designed to perform instant, continuous scanning over a large roof area while being able to detect as little as 2% excess moisture to a depth of up to 6 inches, covering as much as 100,000sq ft in a normal working day. Multiple ranges of sensitivity provide the capability to scan a wide range of roof construction types, allowing inspection of even very thin structures. There is no need for a special permit and transport by road or by air is simple with our flight ready case.


Dec Scanner - Roofing Moisture Scanner
  • Moisture Scan up to 100,000 sq ft in 1 day.

  • No need for special user permit.

  • Transportation simple by road or air.

  • Can be used for inspection during business hours.

  • No need to clear the buildings occupants.


Lean about the Dec Scanner, Roofing Moisture Scanner

No special operator's license is required to use the Dec Scanner. Training is indispensable but uncomplicated and the basics can be learned from our series of instructional videos and manuals.

As with all tools, the Dec Scanner is as good as its operator and nothing can substitute for experience and common sense.


Learn More


Dec Scanner Diagram

"Plumbing the depths: Improved test equipment for today's flat roof design."

Article by Paul Franklin, technical manager at RAM Consultancy RCI Magazine Feb 2015

"The Electrical Capacitance Meter is used to assess the presence and spread of moisture in a roof. The most widely-known unit is called the ‘DecScanner’, which has been in use in the UK and North America for around thirty years…"

Read the full article


Dec Scanner Control Panel

Scanning Area:  24”W x 15.5”D (609mm x 394mm)
Maximum depth of penetration: 6” (152 mm)
Display: Analogue
Measuring Range: 0 to 100 Comparative 
Dec Scanner dimensions: 30”W x 153⁄4“D x 61⁄4”H (762mm x 400mm x 158mm)
Carry case dimensions: 38”W x 20”D x 12”H (940mm x 508 mm x 305mm)
Dec Scanner weight: 24.6 lbs (9.95 Kg)
Total weight (inc. case): 46.5 lbs (21.1 Kg)
Power Supply: 2 × 9 Volt PP3 Batteries (included)
Limitations: Some EPDM, Butyl rubber roofing and other conductive roofing 

ASTM D7954

Standard Practice for Moisture Surveying of Roofing and Waterproofing Systems Using Non-Destructive Electrical Impedance Scanners. 

Significance and Use

5.1 Excess moisture trapped in roofing or waterproofing systems can adversely affect performance and lead to premature failure of roofing or waterproofing systems and its components. It also reduces thermal resistance, resulting in reduced energy efficiency and inflated energy costs. Impedance scans can be effective in identifying concealed and entrapped moisture within roofing or waterproofing systems.

5.2 This practice is intended to be used at various stages of the roofing and waterproofing system’s life such as: during or at completion of installation of roofing or waterproofing system to determine if there was moisture intrusion into the roofing or waterproofing system or underlying materials, at regular intervals as part of a preventative maintenance program, and to aid in condition assessment, or before replacement or repair work, or combinations thereof, to assist in determining the extent of work and replacement materials.


2. Referenced Documents (purchase separately) 

ASTM Standards

C1616 Test Method for Determining the Moisture Content of Organic and Inorganic Insulation Materials by Weight

D1079 Terminology Relating to Roofing and Waterproofing

D7438 Practice for Field Calibration and Application of Hand-Held Moisture Meters

E2586 Practice for Calculating and Using Basic Statistics

F2659 Guide for Preliminary Evaluation of Comparative Moisture Condition of Concrete, Gypsum Cement and Other Floor Slabs and Screeds Using a Non-Destructive Electronic Moisture Meter


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