For homeowners faced with ageing or damaged windows in traditional Irish homes, the decision to restore or replace them can be daunting.

Protected Structure or Not?

First, you need to know if the property is a protected structure. If you are not sure whether it is or not, your local authority has a list that you can easily access and find out.  You will find more details on the Citizens Information website here.

In the cities, there are also designated Areas of Conservation. These are governed similar to above. In both cases, owners are obliged to follow the guidance of the Planning and Development Act Part IV. The windows are an important part of the fabric of the building and hence the heritage. You will need to consult your conservation officer through the local authority office. They will give you appropriate guidance and it is best to consult with them at an early stage. Any alterations to the windows will generally need planning permission.

The Importance of Traditional Windows

Traditional windows are characterised by designs unique to the craftsperson that made them. They are integral to the historical significance of these buildings, reflecting the building techniques of the time. Preserving these windows contributes to the cultural heritage of Ireland, making it essential for homeowners to consider their options carefully.

Historic windows that could be 200 – 300 years old are uniquely placed to give insight into the world of the master craftsmen, and it is a precious legacy that is worth conserving, and also learning from. Furthermore, original windows are a sought-after feature in period properties that add to the overall value.

The principal type of window across Ireland from 1720 onwards, is the sliding sash window. These were mostly all made of solid wood – pitch pine, red deal, or in some cases, oak. This timber was largely imported and is of a much higher quality than any softwood you can buy today. A window that has already stood the test of time, is likely to continue to outlive newer replicas.

Energy Efficiency of Traditional Windows

However, we understand the requirements of modern lifestyle as well as the costs of heating and the sustainability thereof. It is worth noting that the U-value of a single glazed pane is approximately 5.7, whereas that of a double-glazed unit is 1.9, or even 0.7 for vacuum glass such as Fineo.

Bear in mind that these U-values are for the glass alone and will vary once fitted into the window itself. Additionally, Historic Scotland did a study and found that although only 10-15% of heat loss actually occurs through the windows, they are often the first to be replaced, being seen as the big culprits. Draught proofing, on the other hand, can reduce air leakage by 80% and provide an air tightness equivalent to a new building. Timeless Sash Windows have had their sash windows tested independently in the UK and certified as Class 4 – which is the best result on the market.

There is some interesting reading material here from Historic England on draught proofing instead of double glazing.  

Much of our experience over the past 50 years in business, has shown us that both the draught seal itself, and the position of the seal, are crucial in achieving the best results. We use a Schlegel rubber seal that has incredible memory and durability. If you leave a window in a closed position for a long time and then re-open it, the seals will bounce back. They can also withstand accidental painting, whereas the brush seals don’t work as well. The position of the seals are carefully considered at Timeless Sash Windows, to ensure there is no flow of air through the pulley stiles or around the perimeter of the window. This is a tried and tested method.

If your windows are in good condition, therefore, draught sealing can be an excellent solution. If you also have wooden traditional shutters, they are hugely effective at preserving warmth. A Historic Scotland report notes that closing shutters reduces heat loss by over 50% and can give a U-value of 2.2. (Page 89 of the Irish Government Guidelines for Improving Thermal Efficiency of Traditional Buildings) If your shutters are not in good working order, Timeless Sash Windows has fitting teams that are adept at the repair and reworking of the original shutters.

Repairs and Refurbishment of Traditional Windows

It is possible to carry out detailed repairs to the original windows. Even when they may look rotten in sections, our joiners can splice repair the frames in situ, causing minimal impact on the building fabric. In most cases, we then take the sashes back to our joinery where we can work on them in a dedicated environment. At this point, if there is a case to replace non-original glass with double-glazed units, we can do so. This is usually assessed on a case-by-case basis by all the stakeholders.

The windows you get back will be surprisingly new looking, despite their age, and they will retain all of their character. If the original glass is still in situ, they will have additional character in the wonderful warm, dappled light that spreads through the interior as well as refelcting beaitifully from the exterior. Any original glass should be preserved as it handcrafted, mouth-blown glass that is very beautiful.

This is a good solution if the windows are structurally sound but just show signs of wear and tear. Our surveyors will be able to advise on this at the outset. It is also environmentally friendly as it follows the circular model of repair and reuse, reducing waste and the carbon footprint of the window.

The Case for Replacement

In some instances, replacing traditional windows may be the more practical solution. These are some of the reasons that could direct us to this outcome:

• Severe damage and rot across the whole window,
• the original windows have already been replaced with poor timber replicas or uPVC / aluminium,
• a change of use of the building.

If the frames are still in good condition, they can remain in the building and be restored. Then we replace the original sashes with exact matches, usually made from a hardwood such as utile mahogany. This will give the window incredible durability and strength. This type of hardwood is equivalent to a slow-grown pitch pine of the past. Another timber choice is Accoya, which is an acetylated softwood with a guarantee upwards of 50 years anti-rot.

In replacement windows, we can discuss different glass, ironmongery, and paint colour options which will depend on the location and use of the building.

Building Regulations and Traditional Buildings

According to the building regulations 2022 Part L, new windows in dwellings should achieve a U-value of 1.6 or less. This also applies to replacement windows, doors, and rooflights in existing buildings. However, these building regulations do not apply to protected structures. Also, in the case of historic windows, we don’t have standard U-values for the whole unit that we can apply, as each window is unique. This can make compliance with building regulations less straightforward.

Importantly, buildings deemed of historical interest that are not protected, including buildings of traditional construction with permeable fabric, can also be treated differently. (Nearly all buildings constructed in Ireland from medieval times up until 1940 were constructed using traditional methods). The regulation states that in the case of houses of “architectural or historical interest” this demand is inappropriate.  Instead, the best insulation standards that are compatible with maintaining the character should be used. The historical value is deemed on a case-by-case basis by the local council.

With regard to situations in traditional buildings where certified U-values cannot be achieved and default DEAP values are advised:

Studies by SPAB, the IGS, the Heritage Council, and others, have shown, that in traditional buildings, there is a discrepancy between the standardised DEAP values for a particular building material versus the actual case. The reality is that there is varying quality of both the material and craftsmanship.

Traditional buildings are full of irregularities and defective areas, depending on the skills, tools, and technology of the time. As such, if traditional character buildings are required to meet these new minimum standards by applying current DEAP figures, it will put undue pressure on them to meet the minimum standards which may lead to inappropriate renovations or unnecessary demolitions.

The aim instead should be to improve energy efficiency as far as is reasonably practicable. The work should not prejudice the character of the building or increase the risk of long-term deterioration of the building fabric. Ultimately, it can be damaging to require the buildings to improve above their technical capabilities.

Weighing up your options between restoration and replacement windows

You will need to carefully consider each of these:

• Protected structure or not – restoration may be a requirement to comply with local regulations.
• Condition of existing windows – are they structurally sound? Can they be repaired? Can they be aesthetically improved with replacement putty, paint, and ironmongery? Can they be made to operate smoothly and draught sealed?
• Historical significance – consider the historical context of your property.
• Budget – evaluate your budget for the project. There may not be a significant difference in the costs of a refurbishment versus a replacement window, depending on the number of repairs.
• Thermal efficiency – if thermal efficiency and/or acoustics are a top priority, research the performance differences in the various options to see if superior insulation will lead to long-term savings.

Further reading focusing specifically on upgrading traditional buildings of Ireland, published in 2023:

p 87 – 95 of the Irish Government’s guide for Improving Thermal Efficiency of Traditional Buildings.

Your Choices

Ultimately, we are here to help. Our surveyors are highly trained and understand the specifics of traditional buildings in Ireland. We have two dedicated joineries, one for historic and traditional window refurbishment, and the other for the manufacture of new windows and doors. Our fitting teams are specialists in this field and are respectful of your homes.

To find out more, contact our office by phone at 046-9023323 or by email at [email protected]. Our showroom in Trim, Co. Meath is open by appointment only and we can walk you through the many options and offer a tailor-made solution for you.