Page 238 - Construction Waterproofing Handbook

RESIDENTIAL WATERPROOFING 4.13
self-defeating and provide homeowners with no real protection against shoddy work-
manship and materials.
Homebuilders rarely have the knowledge and experience to guarantee installation of
proper transition detailing and otherwise prefer to use simple envelope components such
as vinyl siding that can provide fairly adequate coverage for the elements even when such
detailing is completely overlooked. A perfect example is window perimeter transition to
vinyl siding. Contractors and their subcontractors installing the windows and siding typi-
cally have no knowledge of the proper transitioning between the windows and the siding.
The carpenters framing the house install the windows, and weeks or months later, the
vinyl siding is installed. Siding usually is abutted up to the window perimeter, and no
proper joint is allowed to permit thermal movement during the life cycle of the envelope
at this location. Then, more often as an after thought or for aesthetic reasons only, the con-
tractor will have the painter caulk around the window perimeter to “finish” the project. The
emphasis is on caulk, and the transitioning detail is not even given a chance to succeed
through the use of a proper exterior-grade sealant that is compatible with the vinyl mater-
ial and the window frame. In most cases, this application will work just fine—until a sever
storm is encountered and direct water infiltration occurs. After that, the homeowner will
inspect the window perimeters and find evidence of an ongoing problem usually shown by
damaged or rotting finishes around the window jam and sill and, unfortunately, the pres-
ence of mold. It is only then the homeowner realizes that the simplistic transition detailing
installed by the builder is been inadequate, and this is usually after any warranties have
expired. Unfortunately, since proper transition detailing was not done, the only means to
address the leakage problem is to apply a better exterior-grade sealant that is compatible
with the vinyl siding.
Similar situations occur with all types of residential finishes, including brick and
stucco, as well as other transition details found in homes, such as dryer and hose bib pen-
etrations through the envelope. Preventing these situations can be managed simply by fol-
lowing the guidelines and specifications of the manufacturers of the envelope components
and recommended practices presented in Chaps. 3 and 4 of this book. When manufactur-
ers do not provide sufficient details for transition or terminating their product at such crit-
ical junctures such as below-to-above-grade junctures, then an engineer or architect should
be consulted to design or recommend necessary procedures.
This is why it is recommended that such systems be considered drainage systems and
include a supplement system to protect against water penetration, such as building wrap or
damproofing behind the finished siding. Recognizing that water is likely to pass through
the initial barrier such as siding, especially in sever storms; the building wrap or damproof-
ing can redirect water back to the exterior—provided, though, that proper weep detailing
is incorporated into the envelope. This includes weep holes in the brick facade and proper
installation of a termination strip along the bottom edge of the siding that allows entering
water to permeate back to the exterior.

Roofing
Considering the billions of square feet of residential roofs, leakage directly related to roof-
ing systems is fairly limited. The main reason for this is the incorporation of adequate
steepness in the roof that sheds water off the roof components quickly enough to prevent