PHS 120 Breather Membrane

Economical Breather Membrane

Economical, weathertight breather membrane for supported and unsupported tile, slate and metal roof systems.

Features

Premium Quality
Cost Effective
Technical Support
Installation Guides

The PHS 120 Breather Membrane is a triple layer fabric, external weathertight membrane, made from standard tensile spun bonded polypropylene layers, around a micro porous polypropylene film. It is designed, manufactured and quality assured for use on fully supported or unsupported tile, slate and metal roof systems. PHS 120 Breather Membrane has good vapour permeability, combined with standard tensile strength and wind uplift resistance.

The PHS 120 Breather Membrane is designed as a secondary barrier to wind driven rain and snow, it should not be considered a primary waterproofing layer. The outer, printed layer forms the functional waterproof surface, the middle layer is the breathable waterproof membrane, and the inner layer protects the membrane from abrasion and damage, also giving additional strength. This enables the fabric to allow moisture vapour to pass through, while remaining fully waterproof. The upper surface is beige and printed with the PHS trade name and overlap lines.

Features & Benefits:

Triple Layer Membrane
99.9% Breathable
Clean & Easy-to-Use
Lightweight & Flexible
Excellent Tensile & Tear Strength
Waterproof
Longterm Durability
UV Stable
Warm & Cold Roof Application

Colour	Beige
Size	1.5m x 50m
Mass Per Unit Area	120g/m²
Water Vapour Resistance - Sd Value	0.025m
Tensile Strength Longitudinal	213 N/50mm
Tensile Strength Transverse	148 N/50mm
Elongation Longitudinal	72%
Elongation Transverse	99%
Tear Resistance Longitudinal	141 N
Tear Resistance Transverse	209 N
Water Penetration Resistance	Class W1
Resistance to Fire	Class F
UV Resistance	3 months
Roll Weight	9 kg
Roll Area	75 m²
Material	Breather Membrane
Location	External
System	Defender Weathertight System
Approx Coverage	67 m²

Application

Aplication Guide:

PHS 120 Breather Membrane must be installed in accordance with the relevant sections of BS 5534:2018 and
NSAI S.R. 82:2017 and it’s fixing instructions.
PHS 120 Breather Membrane is designed as a secondary barrier to wind driven rain and snow, it should not be considered a primary waterproofing layer. Whilst the product is UV stable for up to 3 months exposure, good roofing practice dictates that the primary waterproofing finish (e.g. tiles, slates etc.) be applied as soon as practically possible.
PHS 120 Breather Membrane should be unrolled across the roof, starting at the eaves and working up the roof, it must be laid printed side up. With normal slates and tiles the membrane should be installed draped to a maximum 15mm into the void between the rafters in line with BS 5534:2018 and NSAI S.R. 82:2017 it can then be secured with the tiling battens.
This will leave sufficient space between the PHS 120 Breather Membrane and the tiles/slates for drainage and ventilation. When installed as a fully trusses supported system, is laid over on trusses and secured with counter battens. Alternatively the membrane can be installed over counter battens and fixed at 200mm centres using corrosion resistant galvanised clout nails. Tiling battens are fixed to the counter battens leaving a minimum airspace of 25mm between the roof sheet underlay and the tiles for drainage and ventilation.
In unventilated roof systems, vapour control measures are required below the insulation layer to restrict the flow of moist air from within the inhabited building into the roof space.
PHS 120 Breather Membrane should be turned up at abutments at least 100mm to prevent rain and snow being blown into the roof-space. 600mm reinforcing strips should be fixed at hips, ridges and valleys.
At the eaves, a felt support tray should be installed to prevent ponding behind the fascia. PHS 120 Breather Membrane should be laid over the support tray stopping short of the roof tile tails to prevent UV degradation of the underlay.