Traditional sash and case windows are a defining feature of Scotland’s architectural heritage. Maintaining these historic elements requires a blend of traditional joinery skills and modern preservation techniques to ensure they remain functional and weather-tight.

1. Timber Restoration 

Surgical timber restoration is essential for preserving Scotland’s historic windows, which often suffer from rot in the lower sills. Joiners typically perform “Dutchman repairs,” where decayed sections are carefully cut out and replaced with matching pieces of durable timber like Accoya or seasoned pine. By splicing in new wood rather than replacing the entire frame, the structural integrity and original aesthetic are maintained. This targeted approach prevents further decay while ensuring the window remains a lasting and authentic architectural feature.

2. Mechanical Overhaul and Re-cording

A common maintenance task involves renewing the internal mechanism to ensure smooth operation. Over time, heavy cotton sash cords fray and snap, leaving windows stuck or dangerous. Craftsmen remove the staff beads and sashes to access hidden cast-iron weights. Replacing old cords with waxed cotton or durable nylon cores allows for effortless movement. Additionally, many Scottish windows are retrofitted with “Simplex” fittings, allowing the bottom sash to swing inward for safe cleaning—a vital feature for high-rise tenement flats.

3. Glazing and Traditional Sand Mastic

Maintaining the traditional look of a tenement requires careful attention to glazing. Repairs involve replacing cracked panes with hand-blown “cylinder” glass to match original distortions. Old, brittle linseed oil putty is replaced with fresh compound, then finished to shed water. Crucially, the external gap between the timber case and surrounding stonework is sealed using traditional “sand mastic”—a mixture of burnt sand and linseed oil. This remains flexible and breathable, providing a superior seal compared to modern silicone alternatives.

4. Draught-Proofing and Thermal Upgrades

To improve thermal performance without compromising heritage, draught-proofing is a key modern repair. This involves routing discreet grooves into parting beads and staff beads to install brush seals or compression strips. These modifications eliminate rattles and significantly reduce heat loss in older Scottish homes. For those seeking greater efficiency, “slim-line” double glazing can be retrofitted into original sashes. These units mimic the appearance of single glazing but offer modern insulation, making traditional properties warmer and quieter throughout the year.

5. Protective Painting and Finishing

The final stage of restoration is professional decoration using microporous paints. In the damp Scottish climate, these paints allow moisture to escape the timber while providing a robust barrier against wind and rain. Specialist decorators ensure that meeting rails and runways are not over-painted, preventing the sashes from becoming “painted shut.” A high-quality finish protects the delicate moldings and ensures that the extensive repair work remains durable and functional against the elements for at least another full decade of service.