What Are The Challenges Of Preserving Stained Glass Windows?

Stained glass windows have a long history that stretches back all the way to the Middle Ages. This rich history that comes along with the vibrant images reflected in stained glass is something that many older buildings want to keep protected. Preserving stained glass can be successful, as demonstrated by the Canterbury Cathedral stained glass windows, which have been protected since the 12th century! However, the delicate nature of the glass means that stained glass conservation can come with a range of challenges.

In this blog, we’ll go through the main challenges that you may come across during stained glass window conservation. Knowing what challenges to look out for when protecting a stained glass window can help to prevent any damage, keeping the window preserved for years to come!

Frame deterioration

The first challenge to look out for with stained glass protection is signs of any frame deterioration. Due to the age of stained glass windows, over time their frame is susceptible to becoming weaker. Deterioration of the window frame can pose a threat to the stained glass conservation as the glass can become loose or crack due to uneven pressure from the frame. As well as damaging the stained glass, a deteriorated frame can also damage the building itself by allowing water to seep in through the window.

When looking for frame damage on a stained glass window, it is important to know the signs of deterioration for different frames:

• Wooden frames – These window frames, especially when they age, are susceptible to severe weathering, which can cause the wood to rot. If you notice visible cracks, soft spots when pressing the wood, gaps around the frame, or mould, these can indicate that the frame is damaged and you need stained glass window repair.

• Metal frames – For metal frames, inspect for corrosion or rust. These frames can suffer from condensation issues over time, so if the metal frame is corroded, this is a sign that the frame is damaged.

• Stone frames – Stone is a durable material to make a frame from, but over long periods of time it can weaken. With this window frame, look for any cracks, chips, crumbling edges, and noticeable gaps between the stone, as these weaknesses could cause the stained glass to loosen.

Moisture issues

During stained glass conservation, the windows will experience different seasons and many weather conditions. This means that weather-related challenges can occur when preserving stained glass windows, especially if there is a lot of rain. If your stained glass isn’t secured properly, water can etch and pit the glass and harm your window conservation.

If water gets into your stained glass windows, it can erode the metals in the cames or window frame, as well as cause wooden window frames to rot. This erosion will compromise the stability and integrity of the window, which can lead to severe damage to the stained glass. When checking for signs of moisture issues in windows, look out for fogging, water beading, and water droplets on the glass. If you notice water damage, it’s best to consult a professional stained glass repair team.

Broken or cracked glass

As time goes on, the dainty glass in stained glass windows can become susceptible to cracks and breaks. Usually, cracks radiate straight from the source, which can make it easy to identify what is causing the stress to the glass. However, it isn’t always that simple, and there can be many reasons why the stained glass can break, such as:

• Improper installation

• Poor maintenance

• Severe weather conditions

• Vandalism

• Lead fatigue

For effective stained glass protection, we recommend carrying out regular stained glass maintenance to check for any breaks or cracks and having them checked by a specialist every couple of years to ensure that no stained glass window repairs are needed.

Putty deterioration

Window putty is a compound that is used to seal and adhere glass to window frames, and for stained glass windows, putty provides structural stability and helps protect the glass from the weather. Over time, the putty can harden and crack due to age and weathering. When the putty deteriorates, this causes a challenge for stained glass conservation because it loses its adhesion to the glass and the came, making it more susceptible to damage.

If your stained glass window putty has deteriorated, the window may leak air and water, which can cause moisture issues. When looking for signs of damage, check to see if the glass rattles or moves easily in its frame. If so, you should carefully remove the loose or cracked putty sections and apply a fresh layer of glazing putty for effective stained glass protection.

If you’d like to learn more about how Sherriff can help you with your stained glass window conservation, don’t hesitate to get in touch with us on 01202 882208 or send an email to info@leadwindows.co.uk. You can also find our other helpful tips and guides on our website!