Roof tile vent

A roof tile vent is often a moulded plastic product, but can also be made of clay, it is designed to allow air to pass through without letting rain water in. There a number of different styles of roof tile vents which match the different styles of roof tile such as double roman roof tiles, pantile roof tiles, plain roof tiles or non-profile roof tiles, these vents normally have small vents holes within the tile profile and a secondary layer to allow water run off. Other more generic universal types of roof tile vents have a raised section or cover with ventilation beneath, these fit various styles of roof tile. In most cases the underside of the venting tile will have a downstand and a lip, to allow to penotrate the roofing layer beneath the battons above the rafters, (breater membrane, felt or waterproofing), to achieve ventilation, whilst sealing the joint. In some cases it may be fitted with extra attachments to allow ventilation ducts such as from a bathroom extract to be connected directly.

In a cold roof scenario, the insulation and air tightness barrier is normally in line with the ceiling of the upper most rooms, rather than the pitch of the roof itself. Keeping the uninsulated roof space ventilated can be important to prevent moisture build-up, mould and potential damage to timber rafters, particularly where non breathable felt or bitumen products are used. Increased moisture from warm air and activity in living spaces below can build up in the cold roof space above, condense on surfaces and with out good air flow can cause structural damage over longer periods.

Roof tile vents are one way of introducing air flow into a cold roofs to remove moisture build up, other options are felt lap, slate, soffit, fascia and ridge vents. In some cases where levels of insulation are increased above the ceiling level this can restrict air flow that traditionally would have come through the sofits or barge board ventilators. Roof tile vents can be installed higher up the roofpitch, thus not being restricted by the increased levels of insulation.

For further information on the ventilation of cold roofs guidance should be sought in Aproved Document C "Site preparation and resistance to contaminants and moisture" section C2.

[edit] Related articles on Designing Buildings

• Cold roof.
• Condensation in buildings.
• Cross ventilation.
• Domestic roofs.
• Flat roof defects.
• Interstitial condensation.
• Inverted roof.
• Natural ventilation of buildings.
• Roofing defects.
• Thermal bridging in buildings.
• Thermal comfort.
• Trickle ventilation in buildings.
• Warm roof.