ROOF VENTILATION VALVE

The present invention concerns a ventilation valve comprising a bottomless chamber-like upper portion, and a flange portion projecting from the lower edge of the upper portion, the front face of the upper portion comprising a vent hole covered by ventilation ribs.

The useful life of a building depends heavily on removal of moisture from the lower surface of the roofing of the roof. Moisture passing from the inside of the building through vapour barrier and insulation will always accumulate onto the lower surface of the roofing. If the moisture can't be removed, it will decay the structures very quickly. More moisture will be developed in wintertime, when it is colder outside and the percentage of moisture is low. The warm and considerably more humid air inside a building tends to pass through the structures. In wintertime, if there is no ventilation in the walls and the roof, the moisture will condense on the casing of the building and freeze in the winter. During springtime when the ice melts moisture damages will appear. Because warm air always tends to rise upwards, the moisture problem is most severe at roofs. If the building is not provided with a proper vapour barrier or there are holes in it, or if the thickness of insulations is not sufficient and the building doesn't have a proper ventilating slot, the moisture problem becomes even worse. To overcome this problem, ventilation valves can be installed on rooftops. The best point of installation is the ridge of the roof, since it is the highest part of the roof and there is more moisture than elsewhere. Multiform roofs have always been problematic from the point of view of moisture removal. The eaves of the roof have to be constructed so that replacement air can be guided via them.

The main goal in designing the roof ventilation valve according to the present invention was versatility of the valve, so that it could be mounted on a straight face of the roof, on the ridge of the roof and on a roof with a wall extending up from it. This goal was reached with a roof ventilation valve in accordance with the present invention comprising a flange portion with a bendable straight line behind the upper portion. Said bendable line makes it possible to bend the flange either upwards into contact with the wall extending from the roof, or downwards over the ridge of the roof.

A funnel part can be installed to the bottom opening of the ventilation valve, so as to enable use of the valve as an exhaust pipe for a ventilation system or a sewer system.

When the ventilation valves are installed on the ridge, they should preferably be installed alternating on opposite sides of the ridge to provide more efficient ventilation.

The top and the bottom surfaces of the flange portion of the valve include grooves providing a better grip to bitumen.

The ventilation ribs covering the vent hole are shaped slanting downwards at their lower portions to prevent rainwater from entering the valve. Further, a cellular rubber mesh is installed behind the ventilation ribs also preventing rain and snow from driving into the valve, but still permitting the airflow.

In mounted position, the flange portion of the ventilation valve is intended to be glued with bitumen between a surface roofing and a bottom roofing.

The present invention will be described in more detail below with reference to the enclosed drawings, wherein:

Fig . 1 is a perspective view of the roof ventilation valve according to the present invention,

Fig . 2 is a bottom view of the ventilation valve,

Fig . 3 is a side view of the ventilation valve equipped with a funnel,

Fig . 4 is a front view of the ventilation valve of Fig . 3,

Fig . 5 is a cross-sectional view of a ventilation valve installed on the ridge of a roof,

Fig . 6 is a cross-sectional view of a ventilation valve installed on a roof with a wall extending up from the roof,

Fig . 7 is a cross-sectional view of a ventilation valve equipped with a funnel and installed on the face of the roof.

The roof ventilation valve shown in the drawing comprises a chamber-like upper portion 1 with an open bottom, and a flange portion 2 extending from the lower edge of the upper portion. The front face of the upper portion 1 includes a vent hole 4 covered by ventilation ribs 3. In order to ensure versatility of the ventilation valve, a bendable straight line 5 is provided at the flange portion 2 of the ventilation valve, behind the upper portion 1 , so that the flange portion 2 can be bent up or down along said bendable line 5. Thus, the ventilation valve can be installed, for example, on the ridge of the roof 12, so that the vent hole 4 of the ventilation valve is facing towards the eave of the roof, and the bendable line 5 runs along the ridge of the roof, and the bendable portion of the flange portion 2 follows the shape of the roof 12 at the opposite side of the ridge, as illustrated in Fig . 5. Alternatively, the ventilation valve can be installed on the top portion of a roof with a wall extending upwards 13, whereby the bendable line 5 of the flange portion 2 is placed on the border line 14 between the roof and the wall 13, and the bendable portion of the flange portion follows the outer surface of said wall, as illustrated in Fig . 6. Naturally, the ventilation valve can also be installed on the face of the roof, as illustrated in Fig . 7. In this case a funnel part 7 is preferably fitted to the bottom opening 6 of the ventilation valve, enabling the ventilation valve to be connected to an exhaust pipe for a ventilation system or a sewer system. Said funnel 7 is preferably shaped to have the upper portion of the funnel to fit to the bottom opening 6 of the ventilation valve with a sealing joint, and is arranged to a particular angle of the roof. The lower portion of the funnel 7 is advantageously sized to fit in a given standard-sized pipe end.

Grooves 8 are formed on the upper and lower surfaces of the flange portion 2 of the valve, providing a better grip to the bitumen, the bitumen being used for attaching the ventilation valve in place around a hole 15 formed in the roof. First, the flange portion 2 is glued to the bottom roofing attached to the boarding of the roof, and then the surface roofing 11 of the roof is glued on the flange portion 2, leaving only the upper portion 1 of the ventilation valve uncovered. In the disclosed embodiment, the grooves 8 of the flange portion 2 run in parallel, on one hand from the bendable line 5 around the bottom opening 6 of the upper

portion 1 of the ventilation valve, and on the other hand parallel to the bendable line 5 on the bendable portion of the flange portion 2, respectively.

The ventilation ribs 3 covering the vent hole 4 are shaped to include a front part that slants downwards, so as to prevent rainwater from getting inside through the ventilation valve. Further, a cellular rubber mesh 9 is installed behind the ventilation ribs 3 also to prevent rain and snow from driving into the valve, but still permitting airflow.