Case of the Month: An Assortment of Water Leaks

May 1, 2013 by

A general contractor built his own home. Rainy weather led to numerous water leaks through the window framing, roofing, and around the porch. He used several subcontractors and was about to sue for faulty workmanship. GEI was called in to inspect the leaking areas and identify and determine the predominant cause and approximate age of the damage seen.

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Water leaks were found in the garage roof, the master bedroom balcony, the first-floor level bedroom, the laundry area by the bedroom, the first-floor bathroom, the under stairs closet, and the custom Fleetwood windows.

The garage roof was inspected when the owner rolled back the blue plastic tarpaulin sheeting that was temporarily covering it. The drains from the perimeter of the garage roof showed that the leaf barrier mesh covering had been removed from the drain entry of some of the roof outlets. The drain entry was, in several places, ineffectively sealed with tar around the downspout attachment.

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The downspout attached to the drain entry was, in each case, a square section metal downspout connecting to a circular outlet. The upper end of the downspout was poorly manipulated into the discharge from the garage roof perimeter. The garage roof covering did not appear to have any unsealed penetrations by pipes or ducts. However, the inner edge seam by the perimeter gutter appeared not to be sealed around the entire perimeter, thus allowing water penetration into the roof structure.

Poor technical detailing of the seams between the edge of the bituminous felt and the base material of the edge gutter resulted in movement of the felt by expanding and shrinking when subjected to fluctuating temperatures. The resulting flexing of the felt was not matched by the more rigid form of the gutter material, resulting in separation of the felt from the gutter. Following such separations, the tar or other adhesive used was not able to retain its hold on the base material, allowing water to seep between the base material and the underside of the felt when the gutter filled. The edge gutter was very shallow (approximately 1/2 inch to 1 inch), resulting in rapid filling during rainstorms and subsequent movement of water into the gapping between the felt and the base gutter material.  When the drain outlet was clogged to any depth with leaves or other debris, it added to the likelihood that the gutters would remain filled and that there would be continued leakage after a rainstorm. The garage roof covered the bedroom, bathroom, laundry room, and garage.

The master bedroom balcony surface was ceramic tileing. Several of the grouted joints had visible cracking. The outer edge of the balcony had an attached steel railing. The drip edge of the bedroom balcony was coated with mortar and the mortar was cracked. The underside of the balcony had a longitudinal crack with visible water drips when it rained.

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The grout placed between the tiles on the balcony had no sealer on the upper surface. This allowed natural cracking through expansion/contraction cycles resulting from heat/cold cycles to produce a multitude of channels for the later rainfall to leak through. Further, the slope of the balcony was inadequate. Water collected and soaked into the grout. Ceramic tiles are impervious to water but the repeated cycles of soaking the cracked grout resulted in water seeping through the grout to the ceiling below.

Another source of leakage was the stucco around the windows. Stucco applied to walls is designed to protect the underlying tarpaper and timber framing from water. When stucco cracks because of earth movement, expansion/contraction, and other related movement of the building envelope, the path for moisture entry is then designed to be resisted by the underlying layer of tarpaper. Tarpaper, when applied around a window, particularly a window that has a sloping head, can be a difficult material to use to ensure complete coverage for a watertight seal. There was cracking to the exterior stucco because of earth movement and flexure of the building envelope. The subsequent exposure to rainfall resulted in moisture seeping through the difficult area of waterproofing to the interior plaster finishes under the stairway.

The drain outlet for the roof above the first floor bathroom was embedded in white sealant mastic. This had cracked and failed to ensure a watertight seal against the downspout. This mastic failure had led to water collecting in the low spot of the drain outlet and rising up to flood into the defective seal between the roof finish and the drain outlet and then to the wall and roof. The construction of the roof allowed water collecting under this drain to move toward the window header and to infiltrate the bathroom window.

The windows in the front entry porch had neoprene gaskets to seal the window glazing into the frame. The gaskets were, in several places, disturbed in their placement, allowing ingress  of water.

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The underlying cause of the gasket failure was failure of the seal to be completely applied during the manufacturing process. When the glazing was inserted into the frame, during final assembly, some parts of the gasket were not sufficiently lubricated at the glazing edges, resulting in failure of the gasket to “lip” successfully over the glazing’s edge. Therefore, when a tight fit was not made, water from rainfall ran over the glazing to meet with a lower edge gasket improperly fitted. The water then flowed through the frame construction to the interior of the window unit.

Based on the foregoing, the approximate age of the damages noted was at least six months prior to the date of our inspection. With our report in hand, the homeowner was now well prepared for his lawsuits.

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