Modern architecture increasingly features roof lanterns as a way to flood interior spaces with natural light, create architectural interest, and improve energy efficiency. Successful roof lantern installation depends on careful planning and precise construction. One of the most critical aspects of this process is the upstand, the kerb that supports the roof lantern on a flat roof. Ensuring the upstand is perfectly square, correctly measured, and accurately dimensioned can prevent leaks, improve structural integrity, and simplify installation.
For homeowners, builders, and architects, understanding the role of a square upstand is essential. Following a detailed roof lantern installation guide, including steps for measuring for roof lantern, determining upstand dimensions, and squaring the kerb, ensures the finished installation performs as intended, both aesthetically and structurally. This article explores practical steps, highlights common challenges, and guides readers through creating durable, leak-free roof lantern installations.
Why the Upstand Matters in Roof Lantern Installation
The upstand, or kerb, is the raised section of the flat roof on which a roof lantern sits. It provides structural support, ensures the lantern is elevated for proper drainage, and creates a secure interface for waterproofing membranes. A poorly constructed or uneven upstand can compromise even a high-quality lantern, resulting in water pooling, condensation, and visible misalignment. A correctly squared upstand simplifies installation, maintains long-term performance, and ensures the roof lantern is visually and structurally aligned.
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Measuring for a Roof Lantern
Accurate measurement is the foundation of a successful installation. Start by determining the ideal location, considering daylight orientation, roof access, internal layout, and structural support. Measuring the roof opening precisely is crucial; take multiple measurements along the kerb to account for any irregularities. When calculating dimensions, allow space for the frame and flashing. Most roof lantern frames sit inside the upstand, requiring a few centimeters of tolerance on each side. It is equally important to check that the roof area is level and square. Use a spirit or laser level and string lines to identify minor deviations, which can be corrected with insulation or filler materials.
Determining Upstand Dimensions
The upstand dimensions depend on roof pitch, lantern size, waterproofing needs, and structural requirements. Typically, an upstand should be 150-200mm high and wide enough to attach the roof lantern frame securely and accommodate flashing installation. The material—whether timber, masonry, or composite—must be strong enough to support the glazing and frame. Correct upstand dimensions ensure water drains effectively and the lantern sits at the right height, reducing the risk of leaks. For professional flat roof lantern options, see flat roof lanterns.
Squaring the Kerb
A square upstand is critical to ensure the roof lantern fits correctly. If the kerb is out of square, the frame will not sit flush, causing potential leaks, structural strain, and misalignment. To check, measure the diagonals of the kerb; equal measurements indicate the kerb is square. If measurements differ, adjust the corners by trimming or adding material. Use a carpenter’s square to verify all corners are 90 degrees, and check the level again to ensure the upstand is perfectly even. A well-squared kerb simplifies the installation process and enhances the lantern’s long-term performance.
Installing the Roof Lantern
Once the upstand is squared and dimensions verified, installation can begin. First, apply a waterproof membrane over the upstand, overlapping onto the roof surface. Carefully position the lantern frame onto the upstand, ensuring it sits flush and level. Secure the frame using manufacturer-recommended fixings, then insert the glazing units, checking seals and gaskets. Apply flashing and sealant to all edges for watertightness. A final inspection should confirm the lantern is level, square, and free from gaps or misalignment. Professional installation is recommended for large or complex roof structures to ensure safety and performance.
Common Issues and Solutions
Even experienced installers may encounter challenges. An out-of-square kerb can be corrected by measuring diagonals and adjusting corners before placing the frame. An uneven roof surface may require insulation shims or filler boards to create a level base. Water pooling issues can often be resolved by increasing upstand height or adding a slight roof fall. Misaligned frames can be fixed by rechecking measurements and fixings before glazing is installed. Addressing these issues early ensures the lantern performs as intended.
Maintenance Considerations
A correctly installed roof lantern requires minimal maintenance, but regular checks are important to preserve performance. Inspect seals annually, clean glazing with non-abrasive materials, and monitor flashing and waterproof membranes for signs of wear. It is also important to check for condensation or minor leaks after severe weather. Proper maintenance extends the lifespan of the roof lantern and maintains interior daylight levels.
Conclusion
A square upstand is fundamental to a successful roof lantern installation. Following a roof lantern installation guide, taking accurate measurements, verifying upstand dimensions, and squaring the kerb ensures a watertight, structurally sound, and visually appealing result. Proper planning and installation reduce long-term maintenance, improve energy efficiency, and enhance interior daylighting.
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