VapR-free Plus is a multi layer laminate film composite made of polyolefin materials, resulting in a pitched roof underlay that has high vapour permeability but is also highlywater resistant.






Commercial and Domestic

VapR-free Plus is suitable for both Commercial and Domestic buildings, it is the ideal roof underlay for Warm and Cold Pitched Roofs. Manufactured without the use of CFC’s VapR-free Plus is 100% recyclable and is very durable with high tensile and nail tear strength properties. These, coupled with excellent UV and heat stability properties ensure a life-span in excess of 30 years.

BBA Approval

VapR-free Plus membrane has received BBA Approval and complies with BS5534-2014 Code of Practice for slating and tiling and NFRCTB6. Recommendations for the use of vapour permeable membranes in pitched roofs are contained in BS 5250 : 2011 ‘Code of practice for control of condensation in buildings’.

High performance breathable
pitched roof underlay

zone map

Product Data

Roll Width
(linear m)
1.0 1.5
Roll Length
(linear m)
50 50
Coverage/roll/m² 50 75
Roll weight/kgs 7.1 10.65
Rolls/Pallet 49 42

Quality Assurance

BS5534: Anex A
Wind Uplift Resistance
Vapr-free has been approved by the BRE for use in:
Zones: 1-2 with 354mm Batten gauge
Battened lap Exceeds 820
Zones: 1-5 with 250mm Batten gauge
Battened lap Exceeds 1600
Zones: 1-5 with 354mm Batten gauge
Taped lap Exceeds 1600
Zones: 1-5 with 354mm Batten gauge
Integrel Taped lap Exceeds 1600
(see zone map above)

Technical Data

Property Units Value
Weight g/m² 142
Water Vapour Resistance Sd (M) c.0.02
MN/sg 0.18
Water Vapour Transmission g/m²/24 hr 1112
Fire Rating - EN13501-1: 2010
Exposure Times UV Degradation - 3 months

Roof Space Ventilation

Prevention of Condensation
The complete roof construction, ceiling boards, underlay, insulation and roof tiles should be considered as a total roof system with regard to condensation risk, details of which can be found in our BBA certificate.
The risk of condensation is greatest during the first heating period when the moisture levels are high.

Roof Space Ventilation
The NHBC require that for all New Build Homes, ridge or high level ventilation is installed when a vapour permeable membrane such as VapR-free Plus is used. We recommend the membrane should stop 5 to 30 mm from the apex of the roof and a ventilated dry ridge system be used to achieve the required level of ventilation.

VapR-free Plus must be installed with the green printed side face- up and overlapped with the minimum dimensions listed. Trimming is achieved with a sharp knife. When partially supported with a horizontal lap between battens, an extra batten should be introduced 25 mm above the bottom edge. This will restrain the lap from opening under wind uplift.

Weather Tightness
VapR-free Plus is highly water resistant and prevents the ingress of wind driven rain. It can be used as a temporary roof covering and left exposed to the elements, however this period should be kept to a minimum.