All roofs face demanding wind conditions. Location, altitude, coastal exposure, building height and roof design can all affect wind uplift – and the dry fix system required to resist it.

This guide explains the main factors architects, architectural technologists and specifiers should consider when specifying dry fix roofing throughout Ireland.

For detailed guidance on wind forces, roof pressure zones, mechanical fixing and system selection, request Kytun’s Dry Fix Roofing Solutions CPD.

Manufactured in Donegal and independently tested by BRE, Kytun dry fix systems are designed for secure, long-term performance in exposed conditions. Our technical team also supports professionals with product compatibility, system selection and challenging roof details.

How does wind act on a pitched roof?

Wind does not simply push against a roof from one direction.

When it reaches a building, it creates different areas of pressure across and around the structure:

Positive pressure occurs where the wind pushes directly against a surface.

Negative pressure develops as air moves over and around the building, producing suction or uplift.

This uplift can try to pull roof coverings and components away from the structure. The effect is often strongest around:

  • Verges.
  • Eaves.
  • Ridges.
  • Hips.
  • Corners.
  • Leeward roof slopes.

The whole roof cannot therefore be treated as experiencing one uniform wind load. Different roof zones may require different levels of restraint and particular attention to fixing.

What affects wind uplift on a roof?

Several connected factors influence wind uplift:

Location and exposure

Buildings in open countryside, elevated locations and coastal areas may experience greater exposure than buildings protected by surrounding development or landscape.

Two projects in the same region – or even the same town – can face different conditions.

Altitude and topography

Hills, valleys, escarpments and other landforms can change the way wind behaves around a building. Higher sites may also experience increased exposure.

This is particularly important in hilly, mountainous, and coastal areas, where the surrounding landscape can change considerably over a short distance.

Building height and shape

The height, proportions and form of a building influence airflow. Roof pitch, ridge height, overhangs, extensions and adjoining structures can all affect the pressures created.

Roof zones

Wind uplift is not evenly distributed across the roof. Corners, edges, ridges and verges can experience greater forces than central roof areas.

The fixing strategy must respond to these different zones.

Roof covering and system compatibility

Slate type, tile profile, roof pitch and supporting components all influence which dry fix system is appropriate.

A product should not be selected in isolation. The roof covering, battens, underlay, fixings, ridges, hips and verges must operate as one coordinated system.

What is a dry fix roofing system?

A dry fix roofing system mechanically secures and finishes vulnerable parts of a pitched roof without relying on mortar as the primary means of fixing.

Dry fix components can include:

  • Dry verge systems.
  • Dry ridge systems.
  • Dry hip systems.
  • Ridge and hip ventilation rolls.
  • Ridge union brackets.
  • Hip support trays.
  • Mechanically fixed slate and tile trims.

Correctly specified dry fix systems can provide secure, consistent detailing while accommodating normal roof movement. They can also reduce maintenance requirements and avoid some of the variability associated with mortar installation.

However, the term “dry fix” does not automatically guarantee performance. Products must be suitable for the roof covering, supported by appropriate technical evidence and installed in accordance with the manufacturer’s instructions.

Why can’t mortar be relied upon alone?

Mortar has traditionally been used to bed ridge, hip and verge components. But mortar alone does not provide the dependable mechanical restraint expected by current pitched-roofing standards.

It can crack or loosen as the building moves and weather conditions take their toll. Performance can also be affected by preparation, material consistency and workmanship.

Modern roofing practice requires ridge, hip and verge components to incorporate suitable mechanical fixing. Mortar may still be used to create a particular appearance, but it should not be treated as the primary means of securing the system.

BS 5534 provides recommendations for slating and tiling on pitched roofs, including fixing requirements. BS 8612 covers the performance of dry fixed ridge, hip and verge systems.

Naming these standards in a specification is not enough. Their requirements must be translated into compatible products, suitable details and correct installation for the particular building and location.

What are the most common dry fix specification mistakes?

Many roofing problems begin before installation starts.

Common specification oversights include:

  • Reusing a standard detail across sites with different exposure levels.
  • Treating the whole roof as having the same wind pressure.
  • Overlooking the increased forces around corners, ridges and verges.
  • Selecting products without checking compatibility.
  • Considering individual components rather than the complete roof system.
  • Failing to review testing and performance evidence.
  • Leaving critical detailing decisions to be resolved on site.
  • Assuming mortar provides sufficient long-term restraint.
  • Failing to coordinate ventilation requirements with ridge and hip details.

These mistakes can lead to loosened or dislodged components, maintenance problems and water entering the building fabric through failed details.

Early technical input helps identify these risks while they can still be resolved efficiently.

What should architects establish before specifying dry fix roofing?

Before selecting a dry fix system for a project, the design team should establish:

  • The project location and level of exposure.
  • Building height, form and orientation.
  • Roof pitch and geometry.
  • The roof zones likely to experience the greatest forces.
  • The selected slate or tile.
  • Ridge, hip, verge and eaves details.
  • Ventilation requirements.
  • Product and material compatibility.
  • Relevant standards and technical evidence.
  • Manufacturer installation requirements.
  • Any project-specific detailing or support needed.

These factors are interdependent. A change to the roof covering, building form or project conditions may alter the suitability of the proposed system.

Dry fix roofing systems manufactured in Donegal

Kytun has manufactured roofing solutions for more than 35 years.

Our dry fix range includes verge, ridge and hip systems for natural slate, man-made slate and roof tiles. Systems are manufactured using materials including aluminium, galvanised steel, PVC and UV-stabilised polypropylene.

Kytun dry fix systems are independently tested by BRE against the relevant requirements of BS 8612.

We also provide technical support to architects, specifiers, contractors and design teams. This includes help with product compatibility, system selection and challenging roof details.

The objective is not simply to place another product on the specification. It is to help create a coordinated roof system that performs when properly tested by even the harshest of weather.

Learn how to specify dry fix roofing with confidence

Wind loading involves more than looking up a regional wind speed.

Kytun’s Dry Fix Roofing Solutions CPD examines how location, exposure, building form, roof zones, standards and product selection affect pitched-roof performance.

The CPD goes beyond the principles covered here to provide:

  • More detailed specification guidance.
  • Practical system-selection considerations.
  • Product performance and testing information.
  • Discussion of different site and roof conditions.
  • An opportunity to ask questions about current projects.

Sessions can be delivered in practice, live online or on demand.

Request Kytun’s Dry Fix Roofing Solutions CPD and build greater confidence into your next roof specification.

Frequently Asked Questions

Are dry fix roofing systems suitable for exposed locations?

They can be, provided the system is appropriate for the roof covering, building design and site conditions. Exposure, altitude, roof geometry and wind uplift must be considered before selecting products and fixings.

Which areas of a roof are most vulnerable to wind uplift?

Roof corners, verges, eaves, ridges and hips can experience higher wind forces than central roof areas. These zones often require particular attention during specification and installation.

Does dry fix roofing comply with BS 5534?

Compliance depends on the complete specification and installation. BS 5534 provides recommendations for pitched-roof slating and tiling, while BS 8612 covers the performance required for dry fixed ridge, hip and verge systems. Products should have appropriate evidence and be installed according to manufacturer guidance.

Can mortar still be used on a mechanically fixed roof?

Mortar may be used to achieve a traditional appearance, but it should not be relied upon as the primary means of securing ridge, hip or verge components.

Does Kytun provide dry fix specification support?

Yes. Kytun supports architects, specifiers and contractors with system selection, product compatibility and technical roofing details. The Dry Fix Roofing Solutions CPD provides more detailed guidance for professional teams.