How To Ventilate Roof Space

Intake vents located at the lowest part of the roof under the eaves allow cool.

How to ventilate roof space. Roof ventilation this picture represents what is considered to be the best way to ventilate a roof space. Within this category of roof those where the ceiling follows the roof line and those where the ceiling is formed using ceiling joists. In other words the entire vent opening doesn t count as vented space. A double polypropylene cavity batten approximately 13 000 mm2 nfa fixed above every purlin can be used to ventilate the attic space up the roof slope but the actual air movement is very much dependent other factors of the building design.

If your roof peak runs parallel to the street put them on the backside where they ll be less prominent. Place all the roof vents on the same side of the roof. To ventilate a roof space adequately the type of roof structure must first be identified. Vent the roof deck.

The use of an exhaust vent in conjunction with an intake vent uses the natural forces of wind pressure and thermal effect collectively known as the stack effect to ventilate the attic space. Fairly simple stuff fresh air in old stale air out. These roof types are the most common type found in ireland. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed.

In extremes of cold still air condensation overload may occur even where the roof space ventilation complies with the guidance given in bs 5250. If the attic space is going to be conditioned either for living or mechanical purposes or if a home design calls for a vaulted ceiling provision r806 3 in the international residential code calls for the roof deck above the space to be vented continuously from the eave to the ridge. That said air resistance and interference such as vent grates reduces the area of true ventilation. Ventilation can be accomplished using various products and techniques.

The first roof type to be discussed will be pitched roofs. In older properties we must accept that air leakage happens and adequately ventilate the roof space to prevent harmful condensation forming. Too many people believe the importance of roof ventilation is to increase energy efficiency during the summer. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Roof vents are for warmer climates. Different forms of high and low level ventilation are used as well apart from the soffit vents and ridge vents pictured.