Specifying roof windows is an important stage in the design of loft conversions, extensions, and new build developments. The right roof window can maximise natural light, improve ventilation, and contribute to overall energy performance.
This roof window specification guide explains how to specify roof windows, including the key considerations around roof window types, roof window sizes, glazing performance and installation requirements.
When specifying roof windows, professionals need to consider a number of technical and design factors to ensure the product integrates effectively into the building structure. These include the type of roof window required, the appropriate window size, glazing performance, and compatibility with the roof pitch.
Taking these factors into account early in the design process helps architects, developers, and installers ensure the selected roof windows meet both design expectations and regulatory requirements.
Understanding different roof window types is one of the first steps when determining how to specify roof windows. The type required will depend on the roof’s construction, pitch, and the intended use of the space. For a detailed breakdown of the different roof window options available, read our guide to roof window types.
Pitched roof windows are commonly installed in loft conversions and sloped roofs, where they provide both natural daylight and ventilation. In contrast, flat roof windows are typically used in extensions or contemporary developments where the roof structure does not allow for a pitched installation.
Skylights offer a simple daylighting solution and are often installed in unoccupied spaces such as attics or storage areas such as garages, where natural light and basic ventilation are beneficial.
Dakea offer a wide selection of roof windows designed for use across a diverse range of applications, making it easier for specifiers to select the right solution for different project requirements.
Choosing the correct roof window sizes is essential to maximise daylight and maintain balanced proportions within the space.
Sizing should consider the floor area of the room, the spacing between roof rafters, and the overall design of the building. These factors help determine the most suitable roof window dimensions while ensuring the window integrates efficiently within the roof structure. For more detailed guidance on selecting appropriate dimensions, you can read our guide to roof window sizes.
Dakea offer roof windows in standard modular sizes that align with common rafter spacing, helping to simplify installation and reduce the need for structural alterations during construction. To explore available options in more detail, the Dakea roof window configurator can help identify the most suitable window for your project, including the correct size, material, and specification.
Energy efficiency is a critical factor in any roof window specification. The glazing used within the window plays a key role in reducing heat loss, controlling solar gain, and improving overall comfort within the space.
Modern roof windows are typically available with double or triple glazing depending on the level of performance required. Features such as low emissivity coatings and inert gases between glazing panes help reduce heat transfer and improve insulation, helping buildings meet current energy efficiency standards. If you’re looking to explore high performance options in more detail, you can read our guide to energy efficient Dakea roof windows for improved heat insulation and comfort.
Dakea roof windows are available with both double and triple glazing options. For example, the Dakea Ultima Comfort roof window achieves U-values as low as Uw 0.90 W/m²K, delivering strong thermal performance while maximising natural light
Roof pitch and structural compatibility must be considered when determining how to specify roof windows. Each roof window model is designed to perform within specific pitch ranges to ensure effective drainage and weather resistance.
Installers must also consider the structural support required for installation. Larger or more complex roof windows may require additional reinforcement, and in some cases consultation with a structural engineer may be necessary to confirm that the roof structure can safely support the window.
Correct flashing is equally important to ensure a watertight installation. Flashing kits must be compatible with the roofing material and roof pitch to provide proper drainage and weather protection.
Dakea provides detailed installation guides, a range of compatible flashing systems, and professional support to help architects, installers, and contractors select the most suitable roof window for their project and ensure it is installed correctly.
Architects and specifiers require reliable technical information during the design stage to ensure accurate product selection.
Dakea supports professional projects with comprehensive technical documentation, including product specification sheets, BIM Files, CAD Drawings, and installation manuals. These resources help simplify the specification process and allow roof windows to be integrated efficiently into architectural plans.
Dakea is a leading manufacturer of high quality roof windows designed for professionals. With over 80 years of experience in the industry as part of the VELUX Group, Dakea focuses on delivering reliable products that combine strong thermal performance, durability, and practical installation solutions.
The Dakea range includes pitched roof windows, flat roof windows, skylights, and a full selection of flashing systems and installation accessories. These products are designed to maximise natural light while remaining cost-effective for developers and contractors.
In addition to high performing products, Dakea is known for its responsive and knowledgeable customer support. Our team works closely with architects, developers, and installers to provide practical advice and assistance throughout the specification and installation process, helping ensure the right solution is selected for each project.
All Dakea pitched roof windows come with a 20-year guarantee when registered, providing long term peace of mind and demonstrating that our products are built to last.
If you need assistance with roof window specification, our team is here to help. Get in touch with Dakea for expert support, or visit our FAQs for further guidance on products, installation, and specifications.
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