Method and apparatus for moisture detection in exterior sheathing of residential and commercial buildings

• US 6,377,181 B1
• Filed: 02/05/2001
• Issued: 04/23/2002
• Est. Priority Date: 02/05/2001
• Status: Expired due to Term

• Current Assignee: Dryvit Systems, Inc. (RPM International Incorporated)
• Original Assignee: Dryvit Systems, Inc. (RPM International Incorporated)
• Inventors: Watson, Todd E., Kroll, Richard E.
• Primary Examiner(s): Lefkowitz, Edward
• Application Number:
  US09/777,038
• Time in Patent Office: 442 Days
• Field of Search: 340/602, 340/603, 340/604, 340/605, 73/40, 73/405.R, 236/44.A, 236/44.R
• US Class Current: 340/604
• CPC Class Codes: E04B 1/70 Drying or keeping dry, e.g. by air vents using damp-proof courses E04B1/644; using sealings, e.g. sealing masses or foils, E04B1/66; during erection E04G21/28
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 2110/20 Humidity
• CPC Class Codes: G01M 3/16 using electric detection means G01M3/045, G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence
• CPC Class Codes: G08B 21/20 responsive to moisture
• CPC Class Codes: Y10T 137/5762 With leakage or drip collecting

Abstract

An automated device monitors moisture content in exterior sheathing of a building for detecting moisture intrusion into the sheathing walls. A plurality of moisture sensors are embedded in selected exterior walls of the building behind the cladding and are adapted to provide signals representative of the moisture content in the walls at each of the selected locations. A control unit is operatively connected with each of the plurality of moisture sensors for generating an alarm signal when at least one of the signals representative of the moisture content in the plurality of walls is indicative of a moisture content in excess of a predetermined threshold value. Each moisture sensor is preferably in the form of a pair of spaced apart elongate conductive probe members having a substantial portion thereof from a lead end embedded into a substrate of the exterior building walls, and a connection end extending outwardly from the first wall for enabling electrical connection of each moisture sensor to the control unit. An audible or visual alarm is generated when moisture is detected. Electronic communication of alarm signals are further provided for moisture monitoring from a distance.

Claims

1. Apparatus for monitoring moisture content in exterior sheathing of a building, the apparatus comprising:

a first moisture sensor embedded in a first exterior wall of the building, the first moisture sensor being adapted to provide a first signal representative of a moisture content in the first wall;

a second moisture sensor embedded in a second exterior wall of the building, the second moisture sensor being adapted to provide a second signal representative of a moisture content in the second wall; and

,

a control unit operatively connected with said first and second moisture sensors, the control unit generating an alarm signal when at least one of said first signal representative of the moisture content in the first wall and the second signal representative of the moisture content in the second wall exceeds a predetermined threshold value.

2. The apparatus according to claim 1 wherein:

the first moisture sensor has a first resistance characteristic that varies in relation to said moisture content in the first wall; and

,

the second moisture sensor has a second moisture characteristic that varies in relation to said moisture content in the second wall.

3. The apparatus according to claim 2 wherein said control unit includes an excitation signal circuit for generating an excitation signal applied to each of said first and second moisture sensors.

4. The apparatus according to claim 3 wherein:

the first moisture sensor generates said first signal representative of the moisture content in the first wall in response to application of said excitation signal to said first resistance characteristic; and

,

the second moisture sensor generates said second signal representative of the moisture content in the second wall in response to application of said excitation signal to said second resistance characteristic.

5. The apparatus according to claim 4 wherein:

the first moisture sensor includes a first pair of spaced apart elongate conductive probe members having a substantial portion thereof from a lead end embedded into a substrate of said first wall and a connection end extending outwardly from said first wall for enabling electrical connection to the first moisture sensor; and

,

the second moisture sensor includes a second pair of spaced apart elongate conductive probe members having a substantial portion thereof from a lead end embedded into a substrate of said second wall and a connection end extending outwardly from said second wall for enabling electrical connection to the second moisture sensor.

6. The apparatus according to claim 5 wherein the first and second moisture sensors are adapted for embedded placement and operation in an exterior sheathing wall of said building adjacent an outer cladding system including at least a one of a brick cladding, a metal cladding, clapboard siding, vinyl siding, and exterior insulation finish system cladding.

7. The apparatus according to claim 1 wherein:

the control unit is adapted to generate, at a preselected time intervals, a periodic excitation signal applied to each of said first moisture sensor and said second moisture sensor;

the first moisture sensor is responsive to said periodic excitation signal to generate said first signal representative of the moisture content in the first wall; and

,

the second moisture sensor is responsive to said periodic excitation signal to generate said second signal representative of the moisture content in the second wall.

8. The apparatus according to claim 7 wherein the control unit includes a first memory for storing, at each said preselected time interval, a data value of said first signal representative of the moisture content in the first wall and a data value of said second signal representative of the moisture content in the second wall.

9. The apparatus according to claim 8 further including an outdoor temperature and relative humidity sensor coupled to said control unit for sensing temperature and relative humidity of ambient air outside of said building, the control unit further including a second memory for storing, at each said preselected time interval, a data value of said sensed temperature and relative humidity of the ambient air outside of said building.

10. The apparatus according to claim 1 wherein the control unit includes an alarm circuit for generating at least one of a visual alarm and an audible alarm when at least one of said first signal representative of the moisture content in the first wall and the second signal representative of the moisture content in the second wall exceeds said predetermined threshold.

11. The apparatus according to claim 1 wherein the control unit includes a communication circuit for communicating said alarm signal electronically to a location remote from said building.

12. A method for detecting moisture intrusion in exterior sheathing walls of a building, comprising:

for a first initial period, establishing a plurality of datum moisture parameters by;

disposing a set of electrode pairs in exterior sheathing walls of the building;

detecting electrical parameter values between each of the electrode pairs; and

,

storing the detected electrical parameter values as said plurality of datum moisture parameters;

after said first initial period, periodically detecting the electrical parameter value between each of said set of electrode pairs; and

,

generating an alarm signal when, for each of the electrode pairs, a difference between the detected electrical parameter value and the datum moisture parameter is indicative of moisture in said exterior sheathing walls of the building in excess of said datum moisture parameter.

13. The method according to claim 12 wherein:

the step of disposing said set of electrode pairs in said exterior sheathing walls of the building includes inserting a set of elongate electrically conductive electrode pairs directly into said exterior sheathing walls of the building at a plurality of predetermined locations; and

,

the step of periodically detecting said electrical parameter value includes periodically detecting an electrical resistivity between each of said set of elongate electrically conductive electrode pairs.

14. The method according to claim 12 wherein the step of generating said alarm signal includes generating at least one of a visual alarm display and an audible alarm sound when said difference between said detected electrical parameter value and the datum moisture parameter is indicative of moisture in said exterior sheathing walls of the building in excess of said datum moisture parameter.

15. The method according to claim 12 further including the step of providing a control unit operatively connected to each said electrode pair of the set of electrode pairs, the control unit including a first memory for storing the detected electrical parameter value as said datum moisture parameter and a processor for periodically detecting the electrical parameter value between said set of electrode pairs by periodically generating and delivering an excitation signal to each said electrode pair of the set of electrode pairs and determining said electrical parameter value between said set of electrode pairs.

16. The method according to claim 15 wherein the step of providing said control unit includes:

providing a first data log memory operatively associated with said processor for storing a log of said periodically detected electrical parameter values; and

,

providing a communication unit operatively associated with said processor for communicating said alarm signal electronically to a remote location.

17. The method according to claim 16 wherein the step of providing the communication unit includes providing a modem device operatively associated with said processor for communicating said alarm signal electronically to said remote location through an associated standard telephone line.

18. An apparatus for automated moisture content monitoring in exterior sheathing of a building, the apparatus comprising:

a first moisture sensor embedded in a first exterior wall of the building, the first moisture sensor having a first resistance characteristic that varies in relation to said moisture content in the first wall and being adapted to provide a first signal representative of a moisture content in the first wall in response to application of an excitation signal; and

,

a control unit operative connected with the first moisture sensor, the control unit including an excitation signal circuit for periodically generating an excitation signal at regular intervals applied to said first moisture sensor, the control unit generating an alarm signal when the first signal representative of the moisture content in the first wall exceeds a predetermined threshold value.

19. The apparatus according to claim 18 wherein the first moisture sensor includes a first pair of spaced apart elongate conductive probe members having a substantial portion thereof from a lead end embedded into a substrate of said first wall and a connection end extending outwardly from said first wall for enabling electrical connection to the first moisture sensor.

20. The apparatus according to claim 19 wherein the control unit includes a first memory for storing, at each said preselected time interval, a data value of said first signal representative of the moisture content in the first wall.

21. The apparatus according to claim 20 further including:

a plurality of moisture sensors embedded in a plurality of exterior walls of the building, each of the plurality of moisture sensors having a resistance characteristic that varies in relation to said moisture content in said plurality of walls and being adapted to provide signals representative of a moisture content in the plurality of first walls in response to application of said excitation signal; and

,

wherein said excitation signal circuit of said control unit is adapted to periodically generate said excitation signal at regular intervals and applied to each of said plurality of moisture sensors in turn to generate said alarm signal when at least one of said plurality of signals representative of the moisture content in said plurality of walls exceeds said predetermined threshold value.