The new Underlay Lap Ventilator from Hambleside Danelaw offers a low cost and quick fix solution for homes to prevent condensation in poorly ventilated roofs. They can be installed from inside the roof, either DIY or professionally.
Simply fit them between the overlaps in the roofing underlay below the tiles or slates to introduce ventilation openings where there is no proper provision for roofspace ventilation or after an upgrade to the loft insulation. The shallow and tapered design of Hambleside’s ULV suits all commonly encountered rafter spacings and allows for easier fitting between the roofing felt or underlay where the overlaps are tight. A ventilator panel is fitted between each rafter in the lowest underlay lap above the insulation layer in the loft on both sides of the roof. For rafter centres of 600mm and above, the ventilation area can be increased by the installation of two overlapping panels between each rafter.
As few as 18 ventilators on a 2-bedroom property are needed to reduce the risk of condensation. They provide an excellent low cost solution and avoid the need to erect scaffolding which can cause health and safety issues and disturbance to the roof covering.
In new-build construction works, where adequate roofspace ventilation can be provided, conventional roof ventilation openings are recommended. If roof ventilation openings are already present, the air paths can be protected from obstruction by using our Universal Refurbishment Tray Ventilator (HD URT), again simply fitted from the inside of the roof during the insulation upgrade.