Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to the ventilation of a "Mansard"
or "hip" type roof.
By dictionary definition, this is a form of curved
roof, the lower slope of which approaches the vertical and usually
contains dormer windows, while the upper slope is more nearly flat.
This type of roof usually covers the second floor and attic of a
house and has no eaves. More specifically, the side of the house
having this type of roof is coverecl with a false wall. The
attic encloses an air space of triangular cross-section covered
above by the roof and insulated below by insu]ation above the
ceiling of the second floor.
With the mansard roof, in winter, heat loss through the
insulation reaches the attic in the form of hot air whose heat
is transmitted through the roof sheeting and shingles to heat
the snow on the upper part of the roof. The melting causes a
flow of water to the perimeter of the roof which freezes to cause
ice build-up. Frost also builds up on the underside of the roof-
ing boards all around the perimeter. This ice and frost cools
the air inside the attic which meets with warmer air (heat loss) ~
20 coming through the insulation and this causes frost build-up on -
the roofing nails that protrude and on the underside of the roof-
ing, specially towards the roof periphery, where the air is deadest
The frost on the underside of the roof melts and will drip off
as water, as soon as thawing temperatures are encountered. This
cycle repeats itself daily, when the nights are cool and the days
warm. The greater the temperature change the greater the problemO
In the summertime the sun heats the air in the attic. This
stored heat expands through the insulation and heats the room
below making it uncomfortable or putting an extra burden on the
air-conditioning equipment.
There have been a number of attempts to overcome the
; problem. These have involved re-roofing, i.e. by putting new
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shingles over the old ones. Another attempt has been by putting
a metal sheet around the perimeter of -the roof instead of shingles.
A protective built-up border of asphalt or plastic cement of 18
inches to 2 feet wide has been applied around the perimeter of
the roof. Still another attempt has been to blow rnore insulation
into the attic. This creates a further problem, since as the
insulation builds up, and touches the roofing deck, more conden-
sation occurs.
None of the solutions mentioned have been satisfactory.
So it is an aim of the present invention to provide an effective
means of overcoming the problem. This is accomplished according
to the invention by providing a ventilating space between the
roof and the side wall and incorporating in this space special
ventilating means, and providing an exhaust ventilator towards
the top of the roof. With this arrangement, hot air rises from
the bottom of the attic space to the top where it is removed by
the exhaust ventilator to be replaced by fresh air coming in
through the intake ventilator.
A preferred intake ventilator, according to the inven-
tion, comprises a perforated ventilator plate which is to he
placed horizontally. At one slde, the ventilator plate is connect-
ed to a lower support plate which is juxtaposed to the side of
the building over the shingles and nailed or screwed to the wall.
The other side of the ventilator plate is connected to a down-
wardly extending narrow flange which serves as a water-drip which
in turn is connected to a shielding plate which extends upwardly
and diagonally inwardly towards the roof to join an upper connect-
ing flange for juxtaposition to the side of the building at the
junction of the roof. Above the lower end of the support plate
extending in the direction of the ventilator plate is a flange
extending outward to serve as a weather baffle against precipita-
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tion.
Having thus generally described the invention it will
be referred to in more detail by reference to the accompanying
drawings showing preferred arrangements and in which:-
FIGURE 1 is a fragmentary perspective view partly in
section of a house with a mansard roof which
has been modified, after lts normal construc-
tion, to include a ventilating arrangement
according to the invention,
. FIGURE 2 is a fragmentary cross-section -through the
side of the house of Figure 1,
FIGURE 3 is a fragmentary vertical cross-section through
a part of a house with a mansard roof to which
a ventilating arrangement according to the
invention has been applied during its construc- .
tion,
FIGURE 4 is a perspective view on a smaller scale show- ..
ing a house with a mansard roof equipped accord-
ing to the invention, and
FIGURE 5 is an enlarged perspective view showing a
preferred type of ventilator according to the
invention.
Referring more particularly to the drawings, there is - .
shown in Figure 2 a fragmentary perspective view of part of a
house having a mansard or hip type roof which has been modified
to include ventilating means according to the invention. Posts
15 support the insulated wall. Ceiling headers 17 are supported
by the posts 15 and extend around the periphery. Joists 19,
which appear along the front edge of the house and are spaced ..
apart in parallel relationship across the ceiling are carried by . .
the joists 17.
The roof is supported on rafters 27 which extend diagon- .
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ally upward from a bearing connection with the ends of the joists
19. A roofing deck 31 of plywood or boarding is applied on top
of the rafters 27. Shingles 32 cover the roofing deck 31. Between
the ceilin~ rafters 27 and between the respective joists 19 are
end blocks 33 which normally block the space between the joists
19, the roofing deck 31 and the header 17.
A main wall 40 of plywood or wallboard is applied over
the posts 15 and finished on the inside. A false wall is con-
structed as follows. Supporting beams 41 are connected at their
top end to the rafters 27 and extend downward and slightly outward
to a supporting structur'e 43 which connects the beams 41 to the
side wall 40. Plywood or wallboard 34 is applied over the beams
41 extending from the supporting structure 43 to the roof.
The construction described provides a roof indicated
generally by A which meets the wall of the house indicated gener-
ally by B at the edge of the roof and a superimposed false side
C which meets the side B and the roof A at the edge of the roof.
A ceiling-floor C extends from the top of the side and end walls
to provide with the roof A an enclosure of triangular cross-
section which constitutes the attic space. The space is closedat the ends of the building by a wall (not shown) which can be
the same as that of the side or may be a conventional vertical
wall. Insulation 30 covers the ceiling-floor.
The wall and roof construction is modified to ventilate
the attic as follows. A piece 33 of each end block is removed
to leave a space between the top of the end block and the roof.
A strip usually about two inches wide is cut out of the wall
sheeting 34 to provide an air passage 28.
A special intake ventilator D is applied to the house
to cover the opening 28. The ventilator D is an elongated
structure of galvanized sheet metal having a narrow connector
plate 39 which is juxtaposed to the wall board 34 and nailed to
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it. Extending outwardly at a ~5 angle from the connector plate
39 is a spacer plate 37 which, in turn, is connected by a ridge
lock 37a to a perforated ventilator plate ~1 which extends hori-
zontally inward. The ridge lock 37a provides a downwardl~r ex-tend-
ing flange constituting a water-drip structure. On the other side
of the plate 41 is a ridge lock 41a connecting it to a downwardly
extending support plate 43 which i5 jux-taposed to the wall board
3~ and nailed to it. The plate is bent upwards and then outwards
in a flange 45 constituting a weather baffle 45~ The ventilator
device D can be made all in one piece. A preferred material is
30 gauge galvanized sheet metal.
Ventilators E are provided in the roof to allow air to
leave the attic space while preventing ingress of precipitation.
Figure 3 is a fragmentary cross-section through part
of a house which has been designed to ins-tall the applicant's
ventilator system when first constructed. The same numbers are
used, as ln Figure 2, in connection with similar parts except
that th~y are raised by 100.
In this case, about 2 inches of the siding 123 is omitted
0 1 inch below the roofing deck to provide a ventilating opening
p
136. Then, the ventilator ~ of the invention is mounted in place
as shown to cover the opening 136. A metal flashing G is then
a~plied over part of the device ~, and over part of the side wall
~of the house and part of the roof A, as shown, at the corner
underneath the roofing shingles.
Operation
In operation, hot air in the attic space rises under
the roof A and leaves the ventilators E causing air to enter the
at~ic through the ventilator D. So, circulation is induced to
keep the attic ventilated at all times. In winter this prevents
overheating the roof to melt the snow as described above. In
summer, the circulation removes hot air from the attic space so
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as to reduce heating the room below.
