Read on to see how we restored character and improved performance in this Victorian home in Northern Ireland with slimline vacuum glazing in refurbished timber sash windows.

Project Overview

This project involved the careful refurbishment and upgrade of original timber sash windows in a Victorian home in Northern Ireland. The homeowners wanted to preserve the heritage character of the windows while significantly improving thermal efficiency and acoustic performance. Our solution combined traditional joinery skills with modern vacuum glazing technology, delivering both comfort and aesthetic integrity.

Client Objectives

The clients approached us as they heard about Fineo glazing, and were interested in this latest technology to improve the comfort and warmth in their home. However, as their home is a lovely Victorian property, they were keen to preserve the original character and personality of the building. The windows needed to have a complete maintenance overhaul also. Introducing new glass into refurbished windows is an excellent way to improve the thermal efficiency of the windows yet the decor of the home can be protected.  This work aligns with the purpose and vision of Timeless Sash Windows, as we are here to preserve history, elevate comfort, and inspire pride in every home and building we touch.  With the client we also discussed the sustainability and futureproofing of their investment

Our Approach

To achieve the client’s objectives, we carefully removed the sashes and transported them to our Trim-based joinery facility for a full refurbishment. The refurbishment process included:

1. Complete strip and assessment of original timber sashes.

2. Splice repairs to replace damaged or decayed sections while preserving as much original timber as possible. We typically use FSC approved Accoya timber for splice repairs. It is an acetylated softwood with a 50 year anti rot guarantee. Historic windows are usually made fron a slow grown softwood, pitch pine, which is no longer available, yet Accoya, being a softwood, makes an excellent match.

3. Four-coat repainting with low-VOC, water-based specialist exterior joinery paint for a durable, long-lasting finish. We use Teknos paint, which will last for about 7 years before repointing needs to be considered. We recommend an annual wipe over all the windows to remove insects and dirt that could reduce the lifespan of the paint.

4. Vacuum glazing installation, using slimline units (6.7mm) that offer high thermal performance (U-value ~0.7 W/m²K), superior sound insulation and high light transmission.

5. Reputtying and careful refitting of sashes from our skilled glazers.

6. Draught sealing – we use specialist seals in precise positions around the sash to ensure minimal air leakage. Our windows have been independently tested to Class 4 which is the best available on the market.

7. On-site refurbishment of frames, painted in situ to minimise disruption to the household. A dedicated project and fitting crew will work on your home.

This approach allowed the windows to achieve modern thermal and acoustic standards without compromising the historic character of the property.

Results and Benefits

• Thermal Efficiency: noteiceable U-values improved  with vacuum glazing and the Timeless draughtproofing system.

• Acoustic Performance: Noise reduction improved creating a quieter indoor environment.

• Heritage Preservation: Original timber, profiles, and detailing were retained wherever possible.

• Low Disruption: Onsite frame refurbishment and painting reduced the need for prolonged interior disruption.

• Long-Term Reliability: Fineo vacuum glazing units come with a 20 year warranty, providing peace of mind for the homeowners. Additionally, Timeless Sash Windows have more than 50 years proven track record in business, with a continually growing team.

Sustainability and Craftsmanship

At Timeless Sash Windows we have a strong focus on sustainability as one of our core values. We focus on the UN Sustainability Goals 11, 12, 13,and 15 where we can provide the most positive impact and have used these to guide our ESG strategy and policy. Our newly launched production facility in Trim, Co. Meath features 113 kW of PV panels providing 43% of our own electricity and the remaining is sourced fro a certified green provider. Additionally we have a biomass burner which we use to heat aur entire facility suing our own timber and shavings waste.

All materials used on this project were carefully selected for longevity and environmental impact. Low-VOC paints and careful material recovery reflect our commitment to sustainable joinery practices. The project demonstrates how heritage window refurbishment can combine traditional craftsmanship with modern performance, achieving energy efficiency, acoustic comfort, and long-lasting quality.

Homeowner Review

“The restoration of our windows has been very worthwhile. The addition of Fineo glass to the original sash windows has been a real bonus. End result fantastic and the building has kept its character. Sales and project management team were great. The Fitters and Painters who came were professional, on time, polite, tidy and a pleasure to have working at our property over the week long installation.”

Jennifer Ritchie, Marketing and Sustainability at Timeless Sash Windows, 3rd November 2025