Previously commonly used for extensions and sheds, skillion roof designs are now regularly seen in new subdivisions and house designs. At the same time, the performance of modern buildings has also increased, with improvements to glazing, window and door design, and insulation ratings. Together these elements make for greater airtightness in modern homes.
With all these changes, one of the things that hasn’t yet been addressed fully is the provision for ventilation and moisture movement — especially in the roof space. Skillion roof designs in particular have a greater risk of condensation due to low air volumes and restricted air movement. If the roof design and roof system does not allow for ventilation of any uncontrolled moisture, this could not only be detrimental to the structure, but also to the occupants.
When getting involved in skillion roof projects, Thermakraft asks:
- Has ventilation being considered and have provisions being made to provide ventilation to the roof space?
- Does extra ventilation need to be considered?
Roof underlays cannot be considered in isolation when allowing for ventilation, and will only work in conjunction with good building design. A Skillion roof, teamed with a good building design and the correct installation of a high quality roof underlay will mean all the products can work together.
When specifying underlays for skillion roofs, Thermakraft's technical team works with designers to select an underlay suitable for the project. Options which may be suitable for skillion roof designs include:
- Covertek 407: A fire-retardant, absorbent and breathable synthetic self-supporting roof underlay
- Vapor-Shield 101: A polythene underlay suitable for roof construction where condensation and moisture control is required
- Thermabar 344 and 346: Fire retardant foil insulation that can be used as a vapour control layer
- Thermakraft 215: Highly water vapour permeable bituminous underlays
Talk to Thermakraft about upcoming projects and which Thermakraft underlay is best for specific skillion roof designs.