RoofTX Optima Breathable Roofing Membrane 92GSM – 1m x 25m

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 breather membranes, combining excellent vapour permeability with air-barrier properties and resistance to external water penetration.

At just 92gsm, RoofTX Optima is lightweight, flexible and straightforward to install while still offering reinforced properties for reliable performance during roofing work.

This compact roll measures 1m x 25m, providing 25m² of nominal coverage, making it particularly suitable for smaller roofs, extensions, porches, outbuildings, repairs and other projects where a full 50m roll may not be required.

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
• Porches
• Garages and outbuildings
• Renovation projects
• Roof refurbishments
• Smaller roofing projects
• Timber frame construction
• Suitable walling applications

Its low-resistance construction allows moisture vapour to pass through the membrane while helping protect the underlying roof structure against external weather.

Low-Resistance Breathable Roofing Membrane

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

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

Moisture generated inside a building can migrate towards colder areas of an insulated roof. If this moisture becomes trapped, it can increase the risk of interstitial condensation.

By allowing moisture vapour to migrate outward, RoofTX Optima helps support effective moisture management within an appropriately designed roof system.

Helps Reduce Condensation Risk

RoofTX membranes are designed with moisture transfer in mind.

RoofTX Optima allows water vapour to pass outward through the roofing underlay, helping reduce the potential for moisture accumulation within:

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

The complete roof construction should still be designed according to the relevant ventilation, insulation and condensation-control requirements.

Excellent Water Vapour Transmission

RoofTX Optima provides excellent water vapour transmission properties, allowing internally generated moisture vapour to pass through the membrane towards the exterior.

This breathability makes it particularly useful within modern insulated pitched roof constructions where moisture management is an important part of the roof design.

Excellent Resistance to Water Penetration

Although RoofTX Optima allows water vapour to escape, it also provides excellent resistance to external water penetration.

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

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

The finished tiles, slates or other roofing material remain the primary weatherproof covering.

Temporary Weather Protection

During construction, RoofTX Optima can provide temporary protection against:

• Wind-driven rain
• Snow
• Dust
• Wind
• General weather 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 is designed to combine vapour permeability with resistance to air penetration.

These are separate but complementary properties.

The breathable construction allows water vapour to diffuse through the membrane, while its air-barrier properties help restrict uncontrolled bulk air movement.

Reducing unwanted air penetration can contribute towards improved building-envelope performance and help limit heat loss associated with draughts.

Three-Layer Construction

RoofTX Optima forms part of the RoofTX range of three-layer roofing membranes.

This construction is designed to provide a balance of:

• Vapour permeability
• Water resistance
• Strength
• Flexibility
• Durability
• Lightweight handling

The layered construction allows the membrane to provide dependable performance while remaining easy to handle and install.

Reinforced Properties

Despite weighing only 92gsm, RoofTX Optima incorporates reinforced properties designed to provide useful strength and durability during normal handling and installation.

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

Lightweight 92gsm Construction

At 92gsm, RoofTX Optima provides a particularly lightweight roofing underlay solution.

Its low weight makes the membrane straightforward to:

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

This can make installation quicker and easier, particularly on smaller roofs and refurbishment projects.

Convenient 25m² Roll

This RoofTX Optima membrane measures 1m wide x 25m long, providing a nominal area of 25m².

The smaller roll size can be particularly useful for:

• Extensions
• Porches
• Garages
• Garden buildings
• Outbuildings
• Small pitched roofs
• Roof alterations
• Refurbishment projects
• Partial roof replacement
• Smaller membrane requirements

It can reduce the need to purchase a larger roll where only a relatively small roof area needs to be covered.

Suitable for Fully Supported Roofs

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

This can include installations where the membrane is positioned over suitable roof decking or another continuous supporting surface.

Installation should follow the manufacturer’s requirements for the specific roof construction.

Suitable for Unsupported Roofs

RoofTX Optima is also suitable for appropriate unsupported pitched roofing applications.

This provides flexibility across a broad variety of traditional and modern pitched roof constructions.

The appropriate fixing, support and installation method should be followed for the specific application.

Suitable for Warm Roof Systems

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

In warm roof systems, insulation is typically positioned at or above rafter level, keeping more of the roof structure within the insulated envelope.

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

Suitable for Cold Roof Systems

RoofTX Optima is also suitable for relevant cold pitched roof systems.

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

Ventilation requirements depend on the complete roof construction and should be assessed as part of the overall design.

Suitable for Non-Ventilated Roof Systems

RoofTX Optima 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 roofing underlay is required.

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 vapour-permeable membrane is required.

The exact suitability should be checked against the intended wall system and manufacturer’s application guidance.

BBA Agrément Certified

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

The BBA assessment confirms suitability for appropriate applications including:

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

BBA certification provides independent third-party assessment of the RoofTX system for its stated construction applications.

IAB Approved

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

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 complete roof system should still be designed according to project-specific requirements including roof pitch, site exposure, roof covering, batten arrangement, fixing requirements and membrane support.

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 quality management.

25m² Nominal Coverage

Each RoofTX Optima roll measures:

1m wide x 25m long

providing:

25m² nominal coverage per roll

Actual installed coverage will be lower once the required horizontal and vertical laps are taken into account.

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

• Horizontal laps
• Vertical laps
• Roof shape
• Hips and valleys
• Openings and penetrations
• Cutting
• Detailing
• Site wastage

Grey Finish

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

Key Features and Benefits

• Breathable roofing membrane: Allows moisture vapour to escape through the roof construction
• Low-resistance underlay: Designed for excellent 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 vapour transmission: Supports effective moisture management
• Helps reduce condensation risk: Allows water vapour to migrate outward
• Air-barrier properties: Helps resist unwanted air penetration
• Reinforced construction: Provides useful durability during installation
• Warm roof applications: Suitable for appropriate warm pitched roof systems
• Cold roof applications: Suitable for appropriate cold pitched roof systems
• Ventilated applications: Suitable for relevant ventilated roof constructions
• Non-ventilated applications: Suitable for appropriate non-ventilated roof systems
• 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 systems
• ISO 9001 manufacturing: Produced under recognised quality-management procedures
• Flexible and lightweight: Straightforward to handle, cut and install
• Compact roll: Useful where a full 50m roll is not required
• 25m² nominal coverage: 1m x 25m roll
• Grey finish: Distinctive appearance

RoofTX Optima Breathable Roofing Membrane Specification

Why Choose RoofTX Optima Breathable Roofing Membrane?

RoofTX Optima Breathable Roofing Membrane 92GSM – 1m x 25m provides a lightweight and versatile solution for pitched roofing projects requiring a low-resistance breathable roof underlay.

Its 92gsm three-layer construction provides reinforced properties while remaining lightweight, flexible and easy to install. Excellent water vapour transmission helps moisture escape from the roof structure, while excellent resistance to water penetration provides secondary protection beneath the primary roof covering.

Suitable for supported and unsupported, warm, cold, ventilated and appropriate non-ventilated pitched roof systems, RoofTX Optima offers broad application flexibility across new-build, 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.

The compact 1m x 25m roll provides 25m² of nominal coverage, making this size particularly convenient for extensions, porches, garages, outbuildings and other smaller roofing projects where a full-size roll may not be required.