Graham Architectural Products
Homeowner’s Manual
Acoustical Aluminum Windows
4
Water Drainage System
Your Graham windows incorporate a low-point, high-pressure weep system. This system uses small holes
in the window sill, which will route water to the exterior face of the window or door through very small
openings (weep holes). It is customary for water to accumulate in the sill area when raining. There is no
cause for alarm, as this water will weep to the exterior. At times, the small passages get plugged with
excess dirt and debris. This is evidenced by water standing in the sill long after the rain has stopped or
overflowing the sill during a rain period. In most cases, a piece of wire or a pipe cleaner inserted into the
weep holes will clear the debris
(Photo 1)
. In severe cases, the snap-in sill track may be removed to
expose possible clogged openings in the sill frame. Highly-effective weep systems have been engineered
into all Graham window products to allow for water drainage. Please keep weep holes clean and clear so
that water drains to the outside, as designed. To ensure proper operation, keep the sill of your windows
free of dust, and periodically clean your weep holes with a small soft bottle brush or pipe cleaner.
Understanding Condensation & Humidity
Condensation on exterior surfaces of windows and doors occurs because of the improved U-values of the
windows produced today. On clear nights with still, humid air, condensation occurs when moisture-laden
air comes in contact with a glass surface that is below the dew point temperature. “Dew point” is the
temperature at which the air will no longer hold its moisture vapor. Cold air holds less moisture than
warm air. In high-performance windows with low-E glass and argon gas-filled, the outside glass surface
will actually be colder than a similar “regular” window without these features. This is because the high-
performance window is doing its job— reducing heat flow to the outside and preventing the warming of
the exterior surface above dew point. This is not a window defect. Like dew forming on grass and car
hoods, it is a natural phenomenon. Condensation on interior surfaces of windows and doors occurs
because of a combination of high humidity and insufficient air exchange inside the home. In many
windows built using older technologies, there were gaps in the windows where a significant draft could be
felt and where air would flow. This exchange of air, in many cases, was sufficient enough to prevent
condensation from forming. The high-performance windows of today are designed to be as air tight as
possible to reduce heat loss. By doing this, it reduces air flow, and in humid conditions, will allow for
condensation to form on windows. Again, this is not a window defect.
Photo 1
Keep Weep Holes Clear of Debris
