Abstract: A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A movable scanning device carried by a worker has a power supply antenna for supplying power by an electromagnetic wave to the sensor and the worker moves the scanning device to selected ones of the zones. At each selected zone the power supply antenna activates the sensor in the zone and the sensor to emits signals related to the moisture underneath the membrane as detected by the sensor device which are detected and recorded at the mobile scanning device.

Abstract: A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A unique digital code address is assigned to sensor where inputs of the sensors are connected to a single power and signaling cable system using a daisy chain. The serial bus controller is to interrogate each of the sensor devices using the address to identify zones where moisture is detected. A transmitting antenna is provided at each sensor which is switched on when moisture is detected for detecting of the sensor from above the membrane by a utility locate device to confirm the location of the sensor.

Abstract: Leaks in a roof membrane are detected in plurality of separate zones arranged in rows and columns. By applying to the roof in a location underneath the membrane and on top of the deck in each zone at least one length of a moisture detection sensor comprising a substrate carrying two parallel conductors on one surface of the substrate detecting changes in resistance between the conductors so as to detect moisture permeating into the respective zone. The moisture detecting sensors are separate in each zone so as to detect changes in resistance in the respective zone independent of any changes in resistance in other zones so that the system can detect within the rows and columns any zone where changes in resistance occur. In order to detect across the zone, the sensor is applied in a two dimensional pattern for example by two lengths at right angles.

Abstract: A leak in an electrically conductive membrane attached on top of a horizontal roof deck is located by a manually operable carriage which is swept over the upper surface of the membrane on the roof deck. A measuring and switching circuit generates a voltage having a positive attached to the roof deck and a negative attached to conductive brushes on the carriage. The brushes are arranged to form an outer peripheral contact with an inner contact inside the outer contact. There is provided a diode switched into the sensing circuit from the inner conductive brushes so as to reduce the voltage across the deck and the inner brushes relative to the outer brushes. Thus the presence of a leak is detected by the outer set of conductive brushes at distance from the leak and by the inner conductive brush when directly over the leakage site.

Abstract: Leaks in a roof membrane are detected by applying a grid of electrically conductive shielding elements on the upper surface separating the membrane into a plurality of zones and generating a potential difference between the elements and a conductive component such as the roof deck or a layer at the deck. In each zone a respective one of a plurality of sensor conductors is mounted separate from the shielding elements and an electrical potential difference is applied between the sensor and the conductive component such that, in the presence of a leak located within the zone, current flows between the sensor conductor and the conductive component through moisture at the leak for detection of the current or resistance indicative of a leak.

Abstract: In a method of detecting a leak in a water impermeable membrane applied on a roof substrate, an electrical potential is created between a conductive detector on top of the membrane and the roof substrate causing current to flow between the roof substrate and the conductive detector through moisture in any leak in the membrane. The membrane is attached to the roof support substrate by an intervening layer therebetween which can be a primer or an adhesive layer which is caused to be electrically conductive by the addition an electrically conductive material. This allows the conductor on the roof substrate to which the potential difference is applied to be attached onto the roof substrate and covered by the layer underneath the membrane.

Abstract: A leak in a membrane on top of a horizontal roof deck is located by applying conductive wires on the membrane underneath the aggregate in a grid pattern. A measuring and switching circuit generates voltage having a positive attached to the roof deck and a negative attached to the wires. The circuit has a relay for each wire which can be switched between a current sensor system and the negative potential. The sensor system is arranged to sense at each of the wires in turn the current flowing from the roof deck through any leak in the membrane to the wire. A micro-processor operates the relays in turn to connect all the other wires to the negative as a shield while each wire is sensed. From the output of the grid the changes in current in the x and y directions are analyzed to locate the leak in the membrane.

Abstract: A defect in a horizontal or vertical seam at the edge of a roof membrane is detected by applying a DC voltage between the roof deck a probe in the form of a flexible wetted sponge and wiping the sponge probe over the seams. The current to the probe is detected and indicated to the operator so that the operator may determine a maximum current at the defect. The receiver provides an audible signal emitter to the operator and includes a calibration circuit arranged to automatically maintain, despite changes in voltage applied between the roof deck and the peripheral conductor, a “0” set calibration point so as to indicate at the calibration point when zero difference in voltage is detected. Conductors can be applied to the membrane to define an area to be tested within the conductors.

Abstract: A method of monitoring moisture in a building is carried out using moisture detectors, which provide an output resistance value ranging from a dry value in the absence of moisture and different wet values in the presence of moisture depending on the quantity of moisture. Rather than emit an alarm based solely on a moisture threshold, a risk assessment of potential damage is calculated for at least a part of the building using the wet values from the moisture detectors for the sensor zones using as input data the wet values and as a first additional factor a value which is indicative of a total area of the moisture as provided by the number of sensor zones that are responding with a wet value and as a second additional value the number of consecutive time periods that the sensor zone has reported wet value. The calculation can use computer modeling to calculate a risk factor for growth of mold or a risk factor for growth of timber decay fungi.

Abstract: A moisture detection sensor is used in a building structure to detect moisture penetration. The sensor is a flat adhesive tape of a substrate of dielectric, hydrophobic material. Three or four elongate, parallel, conductors are secured to the top surface and a protective layer of non-hygroscopic, water pervious material is secured over two of the conductors so that they are exposed to surface moisture. One or two of the conductors are covered by an insulating layer to prevent moisture access. Pairs of moisture probes along the length of the tape penetrate the insulating layer, the respective conductors and the substrate and to extend into a building component to which the substrate has been adhered. A diode guide arrangement allows a monitoring unit to monitor the exposed conductors for surface moisture and the penetrated conductors for moisture in the component by reversing polarity of the voltage across the conductors.

Abstract: A leak in a membrane on top of a horizontal roof deck is located by applying conductive wires on the membrane underneath the aggregate in a grid pattern. A measuring and switching circuit generates voltage having a positive attached to the roof deck and a negative attached to the wires. The circuit has a relay for each wire which can be switched between a current sensor system and the negative potential. The sensor system is arranged to sense at each of the wires in turn the current flowing from the roof deck through any leak in the membrane to the wire. A microprocessor operates the relays in turn to connect all the other wires to the negative as a shield while each wire is sensed. From the output of the grid the changes in current in the x and y directions are analyzed to locate the leak in the membrane.

Abstract: A leak in a membrane on top of a horizontal roof deck is located by a manually operable carriage which is swept over the upper surface of the membrane on the roof deck. A measuring and switching circuit generates a voltage having a positive attached to the roof deck and a negative attached to conductive brushes on the carriage. The brushes are arranged to form an outer peripheral contact with an inner contact inside the outer contact. Thus the presence of a leak is detected by the outer set of conductive brushes at distance from the leak and by the inner conductive brush when directly over the leakage site.

Abstract: An elongated substantially flat four-conductor moisture detection and location sensor is described. The sensor includes four parallel conductors laminated to a dielectric substrate. Two of the conductors are protected by a water pervious dielectric layer and form the water-sensing element. Two other conductors are covered by a water impervious dielectric layer and are used to loop-back one or more of the water-sensing conductors. Precise location of a water leak location is determined by connecting the four conductors to a resistance bridge. The design allows for the connection of a four-conductor cable to extend the monitoring and detection point to a convenient location without loss of location accuracy.