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Original price was: £51.43.£48.86Current price is: £48.86. Inc VAT
Delivery from £18 - Calculated during checkout based on your address and quantity.Free Delivery on orders over £900Also available for Free Click & Collect from Rossendale, BB4*
Original price was: £51.43.£48.86Current price is: £48.86. Inc VAT
Delivery from £18 - Calculated during checkout based on your address and quantity.Free Delivery on orders over £900Also available for Free Click & Collect from Rossendale, BB4*
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RoofTX 125 Breathable Roofing Membrane 125GSM is a lightweight, low-resistance vapour-permeable roofing underlay designed to provide reliable secondary protection beneath pitched roof coverings while allowing moisture vapour to escape from the roof structure.
Manufactured by Don & Low, RoofTX 125 forms part of the RoofTX range of three-layer breathable roofing membranes and underlays designed to combine vapour permeability, air-barrier performance and resistance to water penetration.
The membrane is suitable for a wide variety of pitched roofing applications, including appropriate warm non-ventilated, cold ventilated and non-ventilated roof systems, as well as suitable walling applications.
At 125gsm, RoofTX 125 provides a practical balance between strength, flexibility and low weight, making it straightforward to handle and install across both supported and unsupported roof constructions.
Each roll measures 1m x 50m, providing 50m² of nominal coverage.
RoofTX 125 is designed for use as a breathable roofing membrane and low-resistance pitched roof underlay beneath discontinuous roof coverings.
Typical applications include:
Its breathable construction helps manage moisture within the roof while providing secondary protection against external weather.
RoofTX 125 is a low-resistance vapour-permeable roofing membrane.
The membrane is designed to allow water vapour to pass through the material rather than becoming trapped within the roof construction.
This is particularly important in insulated roofs where moisture generated inside the building can migrate into colder parts of the roof structure.
Providing a route for this moisture to escape can help reduce the likelihood of condensation accumulating within the construction.
RoofTX 125 has been designed with moisture transfer in mind.
Water vapour can move through the breathable membrane towards the exterior of an appropriately designed roof, helping reduce moisture accumulation within:
The complete roof design should still follow the relevant ventilation, insulation and condensation-control requirements for the specific project.
RoofTX 125 provides excellent water vapour transmission properties, allowing moisture vapour to escape through the roofing underlay.
This high level of breathability makes the membrane suitable for modern insulated pitched roof constructions where effective moisture management is required.
While remaining highly vapour permeable, RoofTX 125 also provides excellent resistance to external water penetration.
This allows the membrane to act as a secondary weather-resistant layer beneath roof tiles, slates or other discontinuous roof coverings.
If wind-driven rain or snow passes beyond the primary roof covering, RoofTX 125 helps protect the underlying insulation and roof structure.
The finished tiles or slates remain the primary weatherproof layer of the roof.
During roofing work, RoofTX 125 provides temporary protection against:
This helps protect the underlying roof structure while the permanent roof covering is being installed.
The membrane is not intended to replace the permanent roof covering and should be covered in accordance with the manufacturer’s installation requirements.
RoofTX 125 is designed to provide air-barrier performance while remaining vapour permeable.
These functions work independently.
Breathability allows water vapour to diffuse through the membrane, while resistance to air penetration helps control uncontrolled bulk air movement through the construction.
Reducing unwanted air leakage can contribute towards improved building-envelope performance and reduced heat loss associated with draughts.
RoofTX roofing membranes use a three-layer construction designed to provide an effective combination of:
The layered structure helps provide reliable performance while keeping the membrane practical to install on site.
RoofTX 125 incorporates reinforced properties designed to provide additional strength during handling and installation.
This helps the membrane withstand normal site conditions while it is being rolled out, positioned, fixed and detailed across the roof structure.
At 125gsm, RoofTX 125 is lighter than heavier-duty membranes within the RoofTX range.
This makes it particularly easy to:
The lighter weight can be advantageous on projects where straightforward handling and fast installation are priorities.
RoofTX 125 can be incorporated into appropriate fully supported pitched roof constructions.
This includes applications where the membrane is installed over suitable roof decking or other continuous supporting surfaces.
Installation should follow the manufacturer’s requirements for the specific roof build-up.
RoofTX 125 is also suitable for appropriate unsupported roofing applications where the membrane spans between structural members.
This provides flexibility across a wide range of traditional and modern pitched roof constructions.
RoofTX 125 can be used within appropriate warm pitched roof systems.
In a warm roof construction, insulation is typically positioned at or above rafter level, keeping more of the roof structure within the insulated envelope.
A low-resistance breathable underlay allows moisture vapour to move outward through the construction.
The membrane is also suitable for relevant cold roof systems.
Cold roof constructions generally position insulation at ceiling level, leaving a colder roof void above.
Ventilation requirements depend on the specific roof construction and should be assessed as part of the complete design.
RoofTX 125 may also be used within appropriate non-ventilated pitched roof systems, subject to the complete roof design and relevant installation requirements.
Its low vapour resistance helps facilitate outward moisture movement where a breathable underlay is required.
The RoofTX range is also certified for suitable walling applications.
RoofTX 125 can therefore be incorporated into appropriate external wall constructions where a breathable, vapour-permeable membrane is required.
Project-specific suitability should be confirmed against the intended wall system and manufacturer’s guidance.
The RoofTX range has received BBA Agrément certification in the UK.
The BBA assessment covers appropriate applications including:
BBA certification provides independent third-party assessment of the membrane for its stated construction uses.
The RoofTX range has also received IAB approval in Ireland, providing independent assessment for appropriate Irish construction applications.
RoofTX roofing membranes form part of a CE and UKCA certified range of roofing underlays and breather membranes.
RoofTX 125 conforms to requirements applicable to underlays for discontinuous roofing under EN 13859-1.
This provides declared performance information for its intended roofing applications.
RoofTX 125 is specified as BS 5534 compliant.
BS 5534 covers slating and tiling for pitched roofs and associated fixing requirements within the UK.
The overall roof system should still be designed according to the specific requirements of the project, including roof pitch, exposure, batten arrangement and underlay support.
RoofTX 125 is manufactured under the control of an ISO 9001 quality management system.
ISO 9001 provides a recognised framework for maintaining consistent manufacturing and quality-control processes.
Each RoofTX 125 roll measures:
1m wide x 50m long
providing a nominal area of:
50m² per roll
Actual effective coverage will be lower once the required horizontal and vertical overlaps are allowed for.
The number of rolls required should therefore be calculated using the total roof area plus an allowance for laps, cutting and site wastage.
RoofTX 125 is supplied in a black finish, providing a clean and professional appearance during installation.
| Specification | Details |
|---|---|
| Product | RoofTX 125 |
| Product Type | Low-Resistance Breathable Roofing Membrane |
| Manufacturer | Don & Low |
| Primary Application | Pitched Roofing Underlay |
| Roll Width | 1m |
| Roll Length | 50m |
| Nominal Coverage | 50m² |
| Weight | 125gsm |
| Colour | Black |
| Construction | Three-Layer Reinforced Membrane |
| Vapour Permeable | Yes |
| Low Resistance | Yes |
| Air Barrier | Yes |
| Water Penetration Resistance | Excellent |
| Suitable for Warm Roofs | Yes |
| Suitable for Cold Roofs | Yes |
| Suitable for Ventilated Roofs | Yes |
| Suitable for Appropriate Non-Ventilated Roofs | Yes |
| Fully Supported Applications | Yes |
| Unsupported Applications | Yes |
| Suitable for Walling | Yes |
| BBA Certified | Yes |
| IAB Approved | Yes |
| CE Certified Range | Yes |
| UKCA Certified Range | Yes |
| Relevant Standard | EN 13859-1 |
| BS 5534 Compliance | Yes |
| Quality Management | ISO 9001 |
| Temporary Weather Protection | Wind-Driven Rain, Snow and Dust |
RoofTX 125 Breathable Roofing Membrane 125GSM provides a versatile combination of breathability, water resistance and lightweight handling for pitched roof applications.
Its 125gsm three-layer construction offers reinforced performance while remaining easy to carry, position and install. Excellent water vapour transmission allows moisture to escape through the roof structure, while excellent resistance to water penetration helps protect the building from wind-driven rain and snow beneath the primary roof covering.
RoofTX 125 is suitable for supported and unsupported, warm, cold, ventilated and appropriate non-ventilated pitched roof constructions, making it suitable for a broad range of new-build, extension and refurbishment projects.
With BBA certification, CE and UKCA certification across the RoofTX range, BS 5534 compliance and conformity with EN 13859-1, RoofTX 125 provides a dependable option for projects requiring a 125gsm breathable roofing membrane, low-resistance roofing underlay or lightweight breathable roof felt.
Each 1m x 50m roll provides 50m² of nominal coverage, making it a practical choice for both residential and larger roofing projects.
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Download Installation Guide |
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Download Technical Data |
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