Page 487 - Construction Waterproofing Handbook

LEAK INVESTIGATION AND DETECTION 13.3
suggests outside assistance is necessary and if emergency repairs are necessitated to pre-
vent further damage and related escalating costs associated with this damage.
The initial leak reports are usually not sufficient to immediately determine the cause
of leakage. It often takes further investigation, including inspections and testing, to pro-
vide sufficient knowledge for effective decisions on how to best make necessary repairs.
The original construction documents also can provide important clues to the leakage
cause(s).

Document review
Prior to the actual inspection, a thorough review of all available construction and as-built doc-
uments should be made, highlighting the general area of the leakage. Make note of any ques-
tionable termination and transition detailing of all envelope components. Determine the
barrier line (described in Chap. 10), and specifically note if it was properly “closed” and hence
ensuring that all individual components of the envelope are transitioned into the adjacent com-
ponent or system with watertight connections. If the original documents do not clearly detail
transition requirements, this should become an area for further visual field inspection.
A basic guide to the review of documents should include

1. Reviewing all individual envelope components. At the building elevation in question,
the as-built drawings should be used to determine each of the individual components
used in construction. Decide if any are likely contributors to the leakage that require
visual inspection in the field. For example glass is not a likely contributor, but precast
panels that have cracked can cause leakage. Highlight all individual waterproofing and
roofing systems used in the envelope construction. Make note of each of these systems
for field inspection. When reviewing these systems remember the 99% principle: that
99% of leakage is attributable to installation problems and not to actual waterproofing
or roofing system failures.
2. Determine the barrier line. Determine if the documents required a weathertight enve-
lope barrier or if there are areas of concern. Do the envelope transition barrier systems
to divertor systems function properly? Document all areas that require further study in
the field inspection.
3. Study termination and transition detailing. Keep in mind the 90%/1% principle, that
90 percent of all leakage can be attributed to 1 percent of the envelope area. Highlight
areas that have no specific detailing provided for in this 1 percent; these areas should
then be carefully inspected in the field. Also, make copies of all provided transitional
detailing to ensure in the field inspection that it was installed as required.
4. Highlight all waterproofing secondary or backup systems specified in the original doc-
uments. These systems usually can not be inspected visually in the field without com-
pleting destructive testing that requires the removal of some or all of the envelope
components to determine if these secondary systems were properly installed. Noting
where these systems should have been installed can assist the inspector during the field
inspection if they are related to the actual area of water infiltration. For example, in
Fig. 13.1 note the multiple secondary systems, including the membrane flashing around
the pipe penetration and the sealant joints under the vent cover. Neither of these sys-
tems would be evident in a visual inspection of the building envelope, but they play
important roles in waterproofing at this 1 percent of the envelope area.