SOW_Attachment_A_-_NCANG_Leak_Investigation_Report_-_Bldg._12.pdf

Leak Investigation Report

Building #12

39563 Warrior Way New

London, NC 28127

31 May 2017

Attachment A - NCANG Leak Investigation - Bldg. 12

Moisture Infiltration Locations

Multiple leaks were reported in the building as shown in the figure below.

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Leak at grade

Roof leak above office

Leak at grade

Attachment A - NCANG Leak Investigation - Bldg. 12

Executive Summary

BACKGROUND

A leak investigation was performed on Tuesday, November 8, 2016. The investigation consisted of a visual observation of the roof and exterior walls, and a water spray test of the roof and through-wall flashing above the office leak.

Observations were documented with representative photographs, which are included in this report. Additional photographs are on file, and are available upon request.

INTERIOR INSPECTION

Building personnel reported that the leaks occur during a typical rain event lasting more than a day, or during driving rain events. Multiple ceiling tiles were removed in the office above below the through-wall flashing these areas and rust was observe on the bottom side of the roof support members (Photograph 1 and 2).

VISUAL ROOF INSPECTION:

The following were observed upon inspecting the single ply roof system, metal coping, counter flashing, and sealants:

1. Detached metal coping termination (Photograph 3).

2. Evidence of ponding water on the roof membrane (Photograph 4).

3. Receiver flashing lap was not sealed (Photograph 5).

4. Through-wall flashing was not adhered to receiver flashing (Photograph 6).

5. Receiver flashing was not lapped (Photograph 7).

6. Missing sealant in control joint (Photograph 8).

7. Open sealant joints at coping termination (Photograph 9).

VISUAL EXTERIOR WALL INSPECTION:

The following were observed upon inspecting the exterior wall, through-wall flashing and sealants:

1. Organic growth at the base of the wall, adjacent to office leak (Photograph 10). The sidewalk does not appear to be sufficiently slope away from the building (Photograph 11);

2. Moisture infiltration was reported a section of the north facing wall (Photograph 12). The sidewalk did not appear to be sufficiently sloped away from the wall (Photograph 13), and the sealant was deteriorated at the base of the wall (Photograph 14).

WATER TEST:

A water spray test was conducted on the NE facing wall above the office leak. A hose bib was utilized at the site, and a water pump was used to increase the pressure at the test location. The roof was tested first for approximately 15 minutes

(Photograph 15), no leaks were identified. The coping termination at the wall was tested for approximately 15 minutes

(Photograph 16), no leaks were identified. The single ply base flashing and termination bar was then tested for approximately 15 minutes (Photograph 17), and no leaks were observed. The through-wall flashing was tested for approximately 10 minutes before water was observed entering the building where the ceiling tiles were previously removed in the office. The area identified that caused the leak was marked on the roof with orange spray paint

(Photograph 18).

CONCLUSIONS:

Based on overall visual inspection, the roof appears to be in good condition. The water test conducted revealed that the leaks were due to issues in the through-wall flashing. The flashing was observed to not be adhered to the receiver metal in several locations. No further observations can be made until the brick is removed, and the flashing condition can be examined more closely. The site grading condition appears to not sufficiently slope away from the building, causing ponding water at the exterior wall and moisture entry into the building along the floor.

RECOMMENDATIONS:

1. Install new through-wall flashing and counter flashing on the NE facing wall above roof level

2. Install two new gravel-stop closures and backer rod and sealant where missing at the NE facing wall above roof level

3. Install new trench drain to address ponding problems near Building 12. Trench drain will connect to a new stormwater pipe that will discharge to grade as shown in the Conceptual Site Plan attached with this report. In addition, demolish existing pavement and install new pavement to slope to trench drain.

ROOF REPAIR

1. 40 linear feet of flashing @ $175/LF = $7,000.00

2. 2 gravel stop closures at $100/EA = $200.00.

3. Backer rod and sealant above roof = $100.00

4. Mobilization/Demobilization = $4,000.00

ESTIMATED BUDGET: $11,300.00

TRENCH DRAIN INSTALLATION

1. Saw cut existing pavement – 127 LF @ $4.55/LF = $578

2. Demolish existing pavement – 68 SQ YDS @ $9.55/SQ YD = $650

3. Install 12” Wide Trench Drain – 118 LF @ $150/LF = $17,700

4. Install Expansion Joint Between Trench Drain and Existing Sidewalk – 118 LF @ $3.54/LF = $418

5. Install 8” Storm Pipe with Pipe Bedding – 98 LF @ $25.50/LF = $2,500

6. Install Cleanout for 8” Storm Pipe – 1 EA @ $500/EA = $500

7. Install Asphalt Pavement – 68 SQ YDS @ $24.35/SQ YD = $1,656

8. Seal Sawcut Between New and Existing Pavement – 127 LF @ $3.71/LF = $472

9. Install Sodding – 1,000 SQ FT @ $520/1,000 SQ FT = $520

10. Install Outlet Protection – 2 SQ YDS @ $104/SQ YD = $208

Attachment A - NCANG Leak Investigation - Bldg. 12

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11. Install Silt Fencing During Construction – 15 LF @ $1.60/LF = $24

12. Construction Contingency (20%) - $5,050

ESTIMATED BUDGET: $30,276.00

Photograph 1 - Removed ceiling tiles in office

Attachment A - NCANG Leak Investigation - Bldg. 12

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Photograph 2 - Rust was observed on bottom side of structural support member.

Photograph 3 - Detached metal termination

Photograph 4 - Discoloration of roof membrane; a sign of ponding water.

Photograph 5 - Receiver flashing lap not sealed

Attachment A - NCANG Leak Investigation - Bldg. 12

Photograph 6 - Through-wall flashing is not adhered to receiver flashing

Photograph 7 - Receiver flashing not lapped

Photograph 8 - Missing sealant in control joint.

Photograph 9 - Open sealant joints at metal coping termination.

Photograph 10 - Organic growth in mortar joints.

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Trench Drain Area #1

Photograph 11 - Sidewalk not properly sloped away from building

Photograph 12 - Moisture intrusion along base of wall

Attachment A - NCANG Leak Investigation - Bldg. 12

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Trench Drain Area #2

Photograph 13 - Sidewalk not properly sloped away from building

Photograph 14 - Deteriorated sealant along base of wall

Attachment A - NCANG Leak Investigation - Bldg. 12

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Photograph 15 - Roof was tested above office

Photograph 16 - Coping termination was tested

Photograph 17 - Base flashing and termination bar was tested

Photograph 18 - Leak identified in through-wall flashing

DESCRIPTION: DATE:

DRAWING NO:

CONCEPTUAL SITE PLAN

STANLY COUNTY, NC - AIRPORT BUILDING 12

NC AIR NATIONAL GUARD WATER INFILTRATION STUDY

EXHIBIT

01/11/2017

DEMOLISH AND INSTALL

NEW ASPHALT PAVEMENT

(APPROX. 610 SQ. FT.)

INSTALL 12" WIDE TRENCH

DRAIN (TYP.) (APPROX. 118 LF)

INSTALL 8" STORM PIPE

(APPROX. 98 LF)

PIPE TO DAYLIGHT

TO GRADE WITH

OUTLET PROTECTION

POTENTIAL UTILITY CONFLICT AREAS (TYP.).

CONTRACTOR TO VERIFY UTILITY LOCATIONS

PRIOR TO CONSTRUCTION.

CONNECT TRENCH DRAIN

TO NEW STORM PIPE.

POSSIBLE UTILITY ROUTE (TYP.).

CONTRACTOR TO VERIFY UTILITY ROUTES

PRIOR TO CONSTRUCTION.

EXISTING CONCRETE

SIDEWALK TO REMAIN

INSTALL SOD OVER

PIPE TRENCH

(APPROX. 1,000 SQ. FT.)

SAWCUT ALONG EXISTING

PAVEMENT (TYP.)

(APPROX. 127 LF)

INSTALL NEW CLEANOUT

SEAL ALONG

ASPHALT CUT (TYP.).

(APPROX. 127 LF)

INSTALL EXPANSION

JOINT ALONG TRENCH

DRAIN (APPROX. 118 LF)

INSTALL SILT FENCE

(APPROX. 15 LF)

NOTE: EXISTING CONDITIONS TAKEN FROM SURVEY BY LUCAS-FORMAN, INC. DATED 11/04/2016.

Attachment A - NCANG Leak Investigation - Bldg. 12

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Trench Drain Area #1

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TRENCH DRAIN INSTALLATION

1. Saw cut existing pavement – 55 LF

2. Demolish existing pavement – 6 SQ YDS

3. Install 12” Wide Trench Drain – 55 LF

4. Install Expansion Joint Between Trench Drain and Existing Sidewalk – 55 LF

5. Install 6” Storm Pipe with Pipe Bedding – 65 LF

6. Install Cleanout for 6” Storm Pipe – 1 EA

7. Patch concrete – 2 SQ YDS

8. Seal Sawcut Between New and Existing Pavement – 110 LF

Attachment A - NCANG Leak Investigation - Bldg. 12

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