Moisture resistant roof vent

A ventilating cap for the ridge of a roof includes a pair of vent parts located on opposite sides of a vent opening cut along ridge board of the roof. A flashing holds an air permeable, moisture-repelling fabric against the outer edge of the vent parts, thereby preventing intrusion of snow and other moisture into the vent opening through the vent parts.

This inventions relates to a ventilating cap for the ridge of a roof. 
Ventilating roof caps are known in the prior art. One such ventilating cap 
is disclosed in U.S. Pat. No. 3,949,657, and includes a pair of elongated 
vent parts mounted on opposite sides of the ridge of the roof. The cap has 
an upper surface which interconnects the part and which bridges across a 
vent opening cut along the ridge of the roof. Each vent part includes in 
inner edge which extends adjacent the vent opening and an opposite outer 
edge. Each vent part is made out of a corrugated material such that a 
large number of passages are defined interconnecting the inner and outer 
edges of each of the vent parts, thereby venting air from the attic or 
upper story of a structure through the vent opening and the passages to 
ambient atmosphere. One problem associated with prior art vent caps is 
that, under certain very adverse weather conditions, wind driven snow or 
rain may be driven through the vent passages and into the attic or upper 
story of the structure, thus causing water damage to the structure. One 
way of solving the problem known in the prior art is disclosed in U.S. 
Pat. No. 4,843,953, in which a perforated flashing member is secured to 
the vent part. The flashing includes a side extending over the outer edge 
of the vent part thereby restricting entry of snow or moisture into the 
passages. One problem associated with this solution, however, is that if 
the perforations in the flashing are small enough to prevent entry of 
moisture into the passages, the vent area may be too restrictive. 
According to the present invention, a flexible, air permeable, moisture 
repelling, woven or nonwoven fabric covers the outer side edges of the 
vent parts and extends over the vent passages to resist penetration of 
moisture into the vent passages. The fabric is held in place by a flashing 
which may be either attached directly to the roof (and be unattached to 
the vent parts), or is attached to the vent parts. Because the fabric 
repels moisture and is air permeable, restriction of the vent passages for 
venting is minimal, but the fabric is effective in repelling moisture 
begin driven into the vent opening through the passages.

Referring now to FIGS. 1 and 3 of the drawings, a ventilating cap generally 
indicated by the numeral I0 is shown mounted on a roof generally indicated 
by the number 12. The remainder of the roof has been broken away are not 
shown for ease of illustration. The roof 12 consists of inclined rafters 
14 and a ridge board 16 which interconnects the rafters. Sheathing 18 is 
mounted on the rafters 14 and is covered by shingles 20. A portion of the 
sheathing 18 on opposite sides of the ridge board 16 has been cut away to 
define a vent opening 22, for venting attic or upper floor of the 
structure covered by the roof 12. 
Vent cap 10 includes a pair of longitudinally extending vent parts 24 and 
26. Each of the vent parts 24,26 extend longitudinally along the roof 12 
substantially parallel to the ridge board 16 and the vent openings 22 cut 
on opposite sides of the ridge board 16. Preferably, after the ventilating 
cap 10 is installed on the roof 12, the ventilating cap may be covered 
with shingles similar to the shingles 20. Each of the vent parts 24,26 
consist of a number of layers or courses 30 of a corrugated material. The 
uppermost layer or cover defines a connecting member 28 which 
interconnects the vent parts 24,26 and extends over the ridge board 16 and 
vent opening 22. The corrugations define passages 32 which extend through 
the vent parts 24,26 substantially parallel with one another between the 
inner edges 34 of each vent part 24,26 to the outer edges 36 thereof. 
Accordingly, the passages 32 define a vent passage which vents the attic 
or upper story of the structure covered by the roof 12 through a vent path 
defined by the vent openings 22 and the passages 32. The passages vent the 
vent openings to ambient atmosphere. More details of the basic ventilating 
cap 10 are disclosed in the aforementioned U.S. Pat. No. 3,949,657. 
According to the present invention, the outer edges 36 of at least one of 
the vent parts 24,26 is covered by a flexible, air permeable, moisture 
repelling fabric generally indicated by the numeral 38. The fabric 38 may 
be a nonwoven, spunbonded fabric consisting of randomly arranged 
polypropylene fibers that is sold as "Typar 3121" by Snow Filtration 
Company, Cincinnati, Ohio. The fabric is held adjacent the outer edge 36 
of the vent part 24 by a perforated metal flashing generally indicated by 
the numeral 40. The flashing 40 includes a pair of side members 42,44 
which are joined at an apex 46. The angle between the members 42 and 44 is 
chosen such that the side member 44 is substantially parallel to the side 
edge 36 when the side member 42 is mounted on the upper proportion of the 
vent part 24. Perforations 48 of the flashing member 40 allow air vented 
from the attic through vent opening 22 and the passages 32 to pass through 
the flashing member 40. Brackets 50 secured to the flashing member 40 and 
are held in place by nails 52 which extend through the vent part 24 and 
into the underlayment 18, as clearly shown in FIG. 3. Portion 54 of the 
fabric 38 curves under the lower edge 56 of the side member 44 and sweeps 
against the shingles 20 mounted on underlayment 18, thereby resisting 
entry of moisture into the vent part 24 around the end 56. 
Referring now to the embodiment of FIGS. 2 and 4, elements the same or 
substantially the same as those of the preferred embodiment retain the 
same reference character, but increase by 100. Since the fabric itself 
repels moisture, and thus prevents entry of moisture into the attic or 
upper story of the structure covered by the roof 112, the flashing 140 
need only support the fabric 138. Accordingly, the flashing 140 may be of 
an extremely open, porous inexpensive material, such as woven wire fabric 
commonly referred to as "chicken wire."Referring to FIG. 2, side member 
158 of flashing 140 is joined to side member 160 thereof at apex 162. Side 
member 160 includes a turned over portion 164 that cooperates with side 
member 160 to define a pocket which receives the fabric 138. Side member 
158 is nailed directly to the underlayment 118 through shingles 120 by 
nails 166. Preferably, a portion 154 of the fabric 138 curves under the 
lower edge of turned over portion 164 and sweeps against the shingles 120 
mounted on underlaymeat 118 in a manner similar to that shown in the 
embodiment of FIGS. 1 and 3, thereby resisting entry of moisture into the 
vent part 124 around the lower edge of portion 164. In this way, existing 
ventilating caps 10 which already have been applied to a roof 112 may be 
retrofitted to prevent moisture ingress into the attic covered by the roof 
112 by applying the flashing 140 and fabric 138 by nailing the side member 
158 to the roof without disturbing the upper portion 128 of the 
ventilating cap 110. The embodiment of FIG. 5 is the same as that of FIGS. 
2 and 4, except that the turned over portion 168 is turned over in a 
direction opposite to the turned over portion 164 of the embodiment of 
FIGS. 2 and 4. Accordingly, a pocket is formed receiving the fabric 138, 
but a portion of the fabric 138 indicated at 170 is bent around apex 162 
to assure that moisture cannot enter around the lower edge of the fabric. 
Referring to FIG. 6, the fabric 138 is crimped to the side member 162. 
FIG. 6 is in all other ways identical to FIG. 5. Referring to FIG. 7, 
instead of being nailed to the roof, the flashing 40 holding fabric 38 is 
installed by using self-tapping screws 172 which extend through the side 
member 160, the fabric 138, the turned over portion 168, and into the vent 
part 124. The embodiment of FIG. 7 is otherwise identical to the 
embodiment of FIGS. 2 and 4.