BUILDING WALL HUMIDITY CONTROL SYSTEM

SYSTEME DE REGULATION DE L'HUMIDITE DANS LES MURS D'UN IMMEUBLE

English Abstract

The invention relates to a system (and devices) for controlling the moisture in framed building walls by controlled forced ventilation. The object of the invention is to improve the long term structural performance of the wall by keeping the moisture in the wall cavity below acceptable levels. The invention can also be used to help identify possible water related breaches or defects in the wall at specific locations.

French Abstract

La présente invention concerne un système (et des dispositifs) de régulation de l'humidité dans des murs d'immeuble encadrés, par une ventilation forcée régulée. L'invention a pour objet d'améliorer les performances structurales à long terme du mur, en gardant l'humidité dans la cavité interne en dessous de niveaux acceptables. L'invention peut également être utilisée pour identifier des éventuelles brèches liées à l'eau ou défauts dans le mur à des endroits spécifiques.

Claims

Claims
Having thus defined my invention, the embodiment of the invention in which an
exclusive
property or privilege is claimed are defined as follows:
1. An improvement in a system to control moisture in an exterior load bearing
wall construction
having a plurality of stud members connected to lower plate and upper plate
hollow and
perforated headers, interior and exterior wall portions and in the stud spaces
thus defined,
moisture/humidity probes are installed such that if the moisture in the
framing members or the
humidity of the air in the stud space exceeds predetermined values, a
moisture/humidity
control mechanism actuates a fan that draws regulated interior air from the
living space, forces
it into the lower headers, the stud spaces and the upper headers and exhausts
it to the exterior
by means of exhaust ports connected to the upper headers through the exterior
wall portion
and continues to operate until such time as the predetermined values are
reached and upon
reaching same, the mechanism then shuts off the fan.
2. An improvement in a system to control moisture in an exterior load bearing
wall construction
having a plurality of stud members and plates connected to lower plate and
upper plate hollow
headers installed externally to the wall construction, interior and exterior
wall portions and in
the stud spaces thus defined, moisture/humidity probes are installed such that
if the moisture
in the framing members or the humidity of the air in the stud space exceeds
predetermined
values, a moisture/humidity control mechanism actuates a fan that draws
regulated interior air
from the living space, forces it into the lower headers, the stud spaces and
the upper headers
and exhausts it to the exterior by means of exhaust ports connected to the
upper headers
through the exterior wall portion and continues to operate until such time as
the
predetermined values are reached and upon reaching same, the mechanism then
shuts off the
fan.
3. The system of claim 1 or claim 2 wherein insulation is installed in the
stud spaces.
4. The system of claim 1 or claim 2 wherein insulation and insulation spacers
are installed in the
stud spaces.
5. The system of claim 1 or claim 2 or claim 3 or claim 4 wherein the
moisture/humidity control
mechanism contains a manual override means to enable manual operation
independent of the
probes.
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Description

CA 02302795 2001-12-17
Description
Technical Field
The invention relates to the exterior wall construction of frame buildings for
residences,
apartments, office buildings and the like. Although but two embodiments of the
present invention
have been illustrated and described, it will be apparent to those skilled in
the art that various
changes and modifications may be made therein without departing from the
spirit of the invention.
Background of the Invention
It is common in the method and materials used to construct frame building
walls, that relatively
airtight cavities are created such that natural ventilation of the said
cavities is prevented or
seriously reduced. Since frame building walls are not absolutely watertight,
the net result over
time is that excess moisture (or humidity) accumulates in the cavities thereby
causing mould to
form and eventually causing structural damage to the wall itself. Also,
present day methods and
materials effectively allow these moisture related problems to go on
undetected for long periods
of time.
The prior art does contain modifications to the common method and materials to
generally
improve air circulation such as described in Canadian application no.
2,148,626 by Fitzgibbon and
in U.S. patent no. 4,393,633 by Charniga. However, all of these are strictly
passive arrangements
that do not measure, control or manage any specific parameters whatsoever.
Because of this, the
net effect that the prior art systems could possibly have on any specific
parameters, such as
moisture content or relative humidity for instance, is unknown. Also, these
systems require
significant changes to the standard framing members which in turn poses a
serious limitation on
commercial feasibility.
The present invention is a system whereby specific parameters such as moisture
content and
relative humidity are measured, managed and controlled without significant
changes to the
standard framing arrangement.
Summary of the Invention
The invention controls moisture in frame building walls by enabling dry
interior air to pass
through the wall cavity by means of a forced ventilation system that is
controlled by a moisture
control mechanism connected to moisture probes installed in the said cavity
and which exhausts
this air to the exterior. The system operates on demand such that when the
probes detect that the
moisture content or humidity in the cavity exceeds predetermined values, the
control mechanism
activates a fan which continues to operate until such time as the
predetermined values are reached
and upon reaching same, the mechanism then shuts off the fan. The air
circulation is achieved by
connecting the fan works to a series of specifically designed hollow headers
and exhaust ports
which form part of the wall itself but do not require significant changes to
the standard framing
arrangement of a conventional building wall.
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CA 02302795 2001-12-17
Brief Description of the Drawings
Figure 1 is a plan view showing a typical general arrangement of the present
invention in a new
construction application.
Figure 2 is a section view of the system of Figure 1.
Figure 3 is an enlarged detailed portion of Figure 2.
Figure 4 is a plan view showing a typical general arrangement of the present
invention in a retrofit
application.
Figure 5 is a section view of the system of Figure 4.
Figure 6 is an enlarged detailed portion of Figure 5.
Detailed Description
Referring to Figures 1, 2 and 3, it can be seen that a typical new
construction general arrangement
is disclosed. A standard exterior load bearing wall is comprised of an
exterior wall portion 1, an
interior wall portion 2, a perforated hollow top plate header 3, a perforated
hollow bottom plate
header 4 and in the cavity thus defined, is found insulation 5, insulation
spacers 6 and
moisture/humidity probes 7. When the probes detect that the moisture or
humidity in the cavity
exceeds predetermined values, a moisture control mechanism 8 activates a fan 9
which draws dry
interior air 10 and forces it through a connector pipe 11 and the components
of the stud space
defined above. The air is allowed to escape to the exterior by means of
exhaust ports 12 located at
the ends of the top plate header 3. Once the predetermined moisture/humidity
values have been
reached, the mechanism 8 shuts off the fan 9. In this way, the invention is
able to keep the
moisture/humidity levels in the cavity below acceptable levels thereby
preventing mould growth
and the structural damage associated with same.
Referring to Figures 4, 5 and 6, it can be seen that a typical retrofit
general arrangement of the
present invention is disclosed. This arrangement is essentially the same as
the one described above
except that the hollow top plate header 3 and the hollow bottom plate header
4, are constructed
by cutting open and expanding inward the interior wall portion 2. Also shown
is a different
configuration for the insulation spacers 6, which, if used, may require a
slightly higher capacity fan
9 to overcome the small increase in friction head loss at the interface of the
insulation 5 and the
inboard edges of the interior and exterior wall portions. With these changes
and the same
previously described control arrangement, this retrofit application can
achieve the same objective
of keeping the moisture/humidity levels in the cavity below acceptable levels
thereby preventing
mould growth and the structural damage associated with same.
Also, for both of the applications described above, the frequent automatic
operation of the system
can act as an early warning that possible water related breaches or defects in
the wall have
occurred at specific locations. This can enable the owners) to take corrective
action in a timely
manner thereby preventing damage that might otherwise grow out of control if
left undetected.
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Representative Drawing