VP400 Protect Membrane is a highly vapour permeable roof underlay. It offers the lowest vapour resistance of any Type LR roofing underlay in its class, and yet it remains completely airtight. It is suitable for use in all pitched roofs. As the airtightness of buildings and dwellings continues to improve due to better workmanship and new practices, it is ill advised to allow uncontrolled air movement within the structure, including through a roof underlay in roofs with no vapour control or air barrier layers. One of the primary functions of roof underlays is to help manage the wind load pressures on the roof. In order to achieve this the underlay should have enough mechanical properties to be able to deflect the wind load pressures safely over the structure. Another essential property is that the underlay be water and airtight. Air permeable underlays allow air to seep through the membrane making it much more difficult to withstand the maximum wind load pressures and driving rain without other surface treatments.

Brand Name	Glidevale
Manufacturer Model No	2487
Condition	new
Gender	unisex
Age Group	adult