Lower Mill

The ground floor of the extension is defined by expansive glazed elevations that connect the main living spaces directly to the landscape.

Two minimal windows sliding systems were installed, forming continuous glazed walls across the façade. One system spans approximately 7 metres, while the second extends to over 12 metres, delivering uninterrupted views across the valley.

The configurations combine fixed and sliding panels to provide both access and large areas of uninterrupted glazing. This balance allows the architecture to maintain a strong connection to the outdoors while ensuring practical day-to-day use.

The design required a careful balance between introducing contemporary glazing and preserving the calm, grounded character of the original mill.

Rather than competing with the historic structure, the sliding glass doors are designed to read as a precise architectural intervention. The minimal aluminium framing reduces visual weight, allowing the materiality of the stone and timber to remain dominant.

This approach demonstrates how sliding glass doors in Wales can be used effectively within sensitive rural and heritage contexts, where restraint and clarity of detailing are essential.

The glazing systems at Lower Mill were engineered to deliver large panel sizes while maintaining ultra-slim sightlines and smooth operation.

The larger installation includes a two-track sliding system with multiple fixed and sliding panes, forming a continuous elevation exceeding 12 metres in width. Individual glass panels weigh in excess of 170kg, requiring precise manufacturing and installation coordination.

A glass-to-glass corner connection removes the need for visible corner framing, allowing the glazing to wrap the building with uninterrupted transparency. This level of detailing is critical in projects where the visual priority is openness and connection to the surrounding landscape.

The specification of the sliding glass doors was developed to ensure consistent performance across a range of environmental conditions.

Double glazed toughened safety glass with low-E coating provides thermal efficiency while maintaining clarity and light transmission.

Flush threshold detailing creates a seamless transition between internal and external spaces, supported by integrated drainage to manage water effectively in exposed rural conditions.

The minimal windows system also delivers high levels of air tightness, weather resistance and structural performance, ensuring that the expansive glazing performs reliably over time without compromising the architectural intent.

The rural location of Lower Mill introduced logistical challenges, particularly due to narrow access roads and the size of the glazing units.

Careful planning and sequencing were required to coordinate delivery and installation, ensuring that large glass panels could be safely transported and installed without damage.

Precision during installation was essential to maintain tight tolerances across the sliding systems, particularly where multiple elements meet to create continuous glazed elevations.

The completed project demonstrates how sliding glass doors in Wales can transform traditional buildings into light-filled contemporary homes while maintaining their original character.

The glazing allows natural light to reach deep into the interior while framing uninterrupted views of the surrounding landscape. At the same time, the minimal detailing ensures that the architecture remains balanced, with glazing acting as a quiet, refined layer within the overall composition.

For architects and developers working on rural or heritage projects, Lower Mill illustrates how large-format minimal glazing can be integrated successfully when supported by careful design, engineering and installation.

• System: Keller minimal windows® sliding door systems
• Configuration: Two separate two-track systems with fixed and sliding panels
• Dimensions: Approx. 12.7m wide and 7m wide glazed elevations
• Panel weights: Individual glass panels exceeding 170kg
• Glass: Double glazed toughened safety glass
• Coating: Low-E coated glass
• Sightlines: Minimal aluminium profiles with approx. 21mm interlock
• Frame finish: RAL 7016 matt finish
• Threshold: Flush threshold with freeway base and integrated drainage
• Locking: Multi-point slim Type 1 shoot bolt locking system
• Special features: Glass-to-glass corner connection and continuous glazed elevations