Specifications

17
CONDENSATION CONTROL
Therefore, any surface with a temperature below 62°F
will condense moisture.
Vapor Retarder
A vapor retarder is a material that restricts the rate of
water vapor diffusion through the ceilings and walls of
a building when below dew point temperature occurs.
Figure 7 illustrates how failure to install the vapor
retarder in the proper location will result in condensation
within the structure. Condensation in your walls or roof
can lead to structural failure. A vapor retarder should be
sealed at all seams.
Ensure the entire pool enclosure design (walls and
ceilings) has a vapor retarder in the correct location.
Care must be taken where walls and roof and walls
and floor meet to ensure there is no breach in the
vapor barrier.
A properly located and installed vapor retarder is the
only means of protecting a building structure from vapor
migration that becomes moisture damage.
Figure 8 is an example of a wall detail with its
temperature gradient. This exercise allows the designer
to identify the dew point temperature in the wall and
where the vapor retarder must be installed.
Window Design
Windows have a relatively low R-value and as a result
will have surface temperatures below the pool room
dew point when it gets cool outside. Exterior windows
will develop condensation on the first cold day unless
measures are taken. The solution to the condensation
problem is to fully blanket every part of the window with
supply air from the HVAC system. It is critical that no
section be missed or it will get cold and condense.
The solution exterior window condensation is simple:
fully blanket them with supply air from the HVAC system.
Air Distribution
Since exterior windows and exterior doors are a
primary condensation concern it is extremely important
that the supply air is focused there. The warm air
from the dehumidifier will keep the window surface
temperature above the dew point temperature and this
in turn ensures the windows and exterior doors remain
condensation free.
There are five basic steps to laying out
the ductwork:
1. Supply air to exterior windows and doors.
2. Supply air to the breathing zone at the deck level and
water surface.
Figure 7 – Do Not Build an Indoor Pool without
a Vapor Retarder
Figure 8 – Pools are different – install the Vapor Retarder
on the Warm Side of the Dew Point