RoofTX Optima Breathable Roofing Membrane 92GSM – 1m x 50m

RoofTX Optima Breathable Roofing Membrane 92GSM is a lightweight, low-resistance vapour-permeable roofing underlay designed to provide secondary protection beneath pitched roof coverings while allowing moisture vapour to escape from the roof structure.

Manufactured by Don & Low, RoofTX Optima forms part of the RoofTX range of three-layer roofing underlays and breathable membranes, combining vapour permeability, air-barrier performance and resistance to external water penetration.

At just 92gsm, RoofTX Optima is one of the lighter membranes within the RoofTX range, making it particularly easy to handle, roll out and install while still providing reinforced properties and reliable weather protection.

Each roll measures 1m x 50m, providing 50m² of nominal coverage.

What is RoofTX Optima Used For?

RoofTX Optima is designed for use as a breathable roofing membrane and low-resistance pitched roof underlay beneath discontinuous roof coverings.

Typical applications include:

• Pitched roofs
• Warm roof systems
• Cold roof systems
• Ventilated pitched roofs
• Appropriate non-ventilated pitched roofs
• Fully supported roof constructions
• Unsupported roof constructions
• New-build properties
• Extensions
• Roof refurbishments
• Renovation projects
• Retrofit roofing projects
• Timber frame construction
• Suitable walling applications

Its combination of low vapour resistance and water resistance makes it suitable for a broad range of modern pitched roof constructions.

Low-Resistance Breathable Roofing Membrane

RoofTX Optima is a low-resistance vapour-permeable roofing underlay.

It is specifically designed to allow water vapour to migrate through the membrane rather than becoming trapped within the roof construction.

This is important within insulated roof systems where moisture generated inside the building can move into colder areas of the roof.

Allowing moisture vapour to escape can help reduce the risk of condensation building up within the structure.

Helps Reduce Condensation Risk

RoofTX membranes have been developed with moisture transfer in mind.

RoofTX Optima allows water vapour to pass outward through the roofing underlay, helping prevent moisture from becoming trapped within:

• Roof insulation
• Timber rafters
• Roof decking
• Structural roof components
• Other elements of the roof build-up

When installed as part of an appropriately designed roofing system, this can help reduce the risk of interstitial condensation.

The complete roof should still be designed in accordance with the relevant ventilation, insulation and condensation-control requirements.

Excellent Water Vapour Transmission

RoofTX Optima provides excellent water vapour transmission properties.

This allows internally generated moisture vapour to pass through the membrane towards the exterior of an appropriately designed roof.

High vapour permeability makes RoofTX Optima particularly useful within insulated pitched roof constructions where effective moisture management is required.

Excellent Resistance to Water Penetration

Although highly breathable, RoofTX Optima also provides excellent resistance to external water penetration.

This allows the membrane to act as a secondary weather-resistant layer beneath tiles, slates or other discontinuous roof coverings.

If wind-driven rain or snow passes beneath the primary covering, RoofTX Optima helps protect the roof structure and insulation beneath.

The permanent tiles, slates or other roof covering remain the primary weatherproof layer.

Temporary Protection Against the Elements

During roof construction, RoofTX Optima can provide temporary protection against:

• Wind-driven rain
• Snow
• Dust
• Wind
• General site exposure

This helps protect the underlying roof structure while the permanent roof covering is being installed.

RoofTX Optima is not intended to act as a permanent exposed roof covering and should be covered in accordance with the manufacturer’s installation requirements.

Air-Barrier Performance

RoofTX Optima combines vapour permeability with resistance to air penetration.

These are separate performance characteristics.

The membrane allows water vapour to diffuse through its structure while helping restrict uncontrolled bulk air movement through the roof.

Reducing unwanted air penetration can contribute towards improved building-envelope performance and help limit draught-related heat loss.

Three-Layer Construction

RoofTX Optima forms part of Don & Low’s range of three-layer roofing underlays.

This construction is designed to provide an effective balance of:

• Vapour permeability
• Water resistance
• Mechanical strength
• Flexibility
• Lightweight handling
• Durability

The layered design helps provide dependable roofing performance while maintaining ease of installation.

Reinforced Properties

Despite its low 92gsm weight, RoofTX Optima incorporates reinforced properties to improve durability during normal handling and installation.

This helps the membrane withstand the stresses associated with rolling out, cutting, positioning, fixing and detailing across the roof structure.

Lightweight 92gsm Membrane

At only 92gsm, RoofTX Optima is particularly lightweight and easy to work with.

The reduced membrane weight makes it straightforward to:

• Carry onto the roof
• Roll out
• Position
• Cut
• Lap
• Fix
• Detail around roof features

This can make RoofTX Optima particularly attractive on projects where fast, straightforward installation is a priority.

Suitable for Fully Supported Roofs

RoofTX Optima is suitable for appropriate fully supported pitched roof constructions.

This can include applications where the membrane is installed over suitable roof decking or other continuous supporting surfaces.

The installation should follow the manufacturer’s requirements for the particular roof build-up.

Suitable for Unsupported Roofs

The RoofTX range is also suitable for appropriate unsupported roofing applications, allowing the membrane to span between structural members where permitted by the roof design.

This provides flexibility across both traditional and modern pitched roof systems.

Suitable for Warm Roof Systems

RoofTX Optima can be incorporated into appropriate warm pitched roof constructions.

In a warm roof, insulation is generally positioned at or above rafter level, keeping much of the roof structure within the insulated envelope.

Using a breathable low-resistance underlay allows moisture vapour to migrate outward through the construction.

Suitable for Cold Roof Systems

RoofTX Optima is also suitable for appropriate cold pitched roof constructions.

Cold roofs generally position insulation at ceiling level, leaving a colder roof void above.

The ventilation requirements will depend on the exact construction and should be considered as part of the overall roof design.

Suitable for Non-Ventilated Roof Systems

RoofTX Optima may also be used within appropriate non-ventilated pitched roof systems, subject to the complete construction and installation requirements.

Its low-resistance breathable construction allows moisture vapour to pass through the membrane, supporting outward drying within properly designed roof systems.

Suitable for Walling Applications

The RoofTX range has also been assessed for suitable walling applications.

RoofTX Optima can therefore be incorporated into appropriate external wall constructions where a breathable, vapour-permeable membrane is required.

The intended wall build-up and manufacturer’s application guidance should be checked before specification.

BBA Agrément Certified

The RoofTX range has obtained BBA Agrément certification in the UK.

The certification confirms assessed suitability for appropriate applications including:

• Warm non-ventilated pitched roofs
• Cold ventilated pitched roofs
• Suitable non-ventilated roof constructions
• Walling applications

BBA certification provides independent third-party assessment of the RoofTX system for relevant construction uses.

IAB Approved

The RoofTX range has also received IAB approval in Ireland, providing additional independent assessment for appropriate Irish construction applications.

CE and UKCA Certified

RoofTX Optima forms part of the CE and UKCA-certified RoofTX range of roofing underlays and breather membranes.

The product conforms to requirements applicable to underlays for discontinuous roofing under EN 13859-1.

This provides declared performance information relevant to its intended pitched roofing applications.

BS 5534 Compliance

RoofTX Optima 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 construction should still be designed according to project-specific factors including:

• Roof pitch
• Site exposure
• Batten arrangement
• Underlay support
• Tile or slate specification
• Fixing requirements

ISO 9001 Quality Management

RoofTX Optima is manufactured under the control of an ISO 9001 quality management system.

ISO 9001 provides a recognised framework for maintaining consistent manufacturing processes and product quality.

50m² Nominal Coverage

Each RoofTX Optima roll measures:

1m wide x 50m long

providing:

50m² nominal coverage per roll

The effective installed coverage will be lower once the required horizontal and vertical overlaps have been allowed for.

When calculating the number of rolls required, allowance should therefore be made for:

• Membrane laps
• Roof shape
• Valleys and hips
• Openings
• Cutting
• Detailing
• Site wastage

Grey Finish

RoofTX Optima is supplied in a grey finish, distinguishing it from other membrane grades within the RoofTX range.

Key Features and Benefits

• Breathable roofing membrane: Allows moisture vapour to escape through the roof construction
• Low-resistance underlay: Designed for high water vapour transmission
• 92gsm construction: Lightweight and easy to handle
• Three-layer membrane: Combines strength, breathability and weather resistance
• Excellent water resistance: Helps protect against wind-driven rain and snow
• Excellent water vapour transmission: Supports effective moisture management
• Helps reduce condensation risk: Allows water vapour to migrate outward
• Air-barrier performance: Helps resist unwanted air penetration
• Reinforced properties: Provides useful durability despite its lightweight construction
• Warm roof applications: Suitable for appropriate warm pitched roof systems
• Cold roof applications: Suitable for appropriate cold pitched roof systems
• Ventilated roof systems: Suitable for relevant ventilated constructions
• Non-ventilated roof systems: Suitable for appropriate non-ventilated applications
• Fully supported applications: Suitable for appropriate supported roof systems
• Unsupported applications: Suitable for appropriate unsupported roof systems
• Wall applications: Suitable for appropriate walling constructions
• Temporary weather protection: Helps protect against wind-driven rain, snow and dust
• BBA certified: Independently assessed by the British Board of Agrément
• IAB approved: Approved for appropriate Irish applications
• CE certified: Part of the CE-certified RoofTX range
• UKCA certified: Part of the UKCA-certified RoofTX range
• EN 13859-1: Conforms to requirements for underlays for discontinuous roofing
• BS 5534 compliant: Suitable for appropriately designed pitched roof installations
• ISO 9001 manufacturing: Produced under recognised quality-management procedures
• Flexible: Straightforward to roll out, cut and detail
• 50m² roll: 1m x 50m nominal area
• Grey finish: Distinctive appearance

RoofTX Optima Breathable Roofing Membrane Specification

Why Choose RoofTX Optima Breathable Roofing Membrane?

RoofTX Optima Breathable Roofing Membrane 92GSM provides a lightweight and versatile solution for pitched roofing projects requiring a low-resistance breathable underlay.

Its 92gsm three-layer construction keeps the membrane easy to carry and install while still providing reinforced properties, excellent resistance to water penetration and excellent water vapour transmission.

RoofTX Optima allows moisture vapour to escape from the roof structure while providing secondary protection against wind-driven rain, snow and dust beneath the primary roof covering.

Suitable for supported and unsupported, warm, cold, ventilated and appropriate non-ventilated pitched roof systems, it offers broad application flexibility for new-build, extension, renovation and refurbishment projects.

With BBA certification, CE and UKCA certification across the RoofTX range, BS 5534 compliance and conformity with EN 13859-1, RoofTX Optima is a practical choice for projects requiring a 92gsm breathable roofing membrane, lightweight low-resistance roof underlay or breathable roof felt.

Each 1m x 50m roll provides 50m² of nominal coverage, making it suitable for both residential roofing and larger pitched roof projects.