When it comes to sash window restoration, there are a number of different methods and materials that can be used. Some sash window restoration companies will opt for more traditional techniques, such as linseed putty and spliced repairs.

Other firms may focus on more modern materials like two-component expo fillers and resinous putty.

Each sash window restoration method and materials have advantages and drawbacks.

However, the decision will be determined by a number of factors, including the building’s status, whether it is listed or not, and the customer’s preferences.

At the end of the day, no matter what materials or techniques are used, the most important is that sash window restoration is done properly.

A good restoration company will take all precautions to ensure that their work is done with care and precision while also preserving the character and style of these historical windows.

So if you’re looking to restore your old sash windows or french doors, it’s crucial that you work with a reputable company that understands both modern techniques and traditional methods in equal measure and can combine both to achieve the best results.

Original sash windows issues

  • Interior side window paintwork failure caused by condensation: This typically occurs when warm, moist air from inside the house mixes with cold on the surface of glass panes. As the moisture begins to condense, it saturates, and droplets of water penetrate the paint, causing cracking and glazing bar decay.
  • The wood surfaces are degrading: This issue can stem from a variety of causes, such as exposure to weather elements and rapid temperature changes. Another contributing factor can be the infiltration of unwanted substances into weaknesses in the surface of the wood, which can eventually lead to flaking or other forms of damage.

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  • Joinery that has been painted over excessively: Windows joinery can also have excessive amounts of paint accumulated over the years. When the paint on windows gets too thick, the area around it becomes weak and easy to break. To prevent this, it is important to remove the excess paint carefully and apply new coats of paint. Ultimately, taking good care of your joinery ensures that your timber windows remain strong and safe for years to come.
  • Stop beads fitted too tightly: If you’re having trouble opening or closing one of the sashes, check the stop beads on the inside of the window that keeps the sliding sash in place. It’s conceivable that one of the stop beads is too tight and prevents the sash from operating properly.
  • Sashes and frames that swell due to water absorption: if a sash or frame is exposed to too much water or high moisture over time, it can swell due to absorption. When this happens, the effectiveness of the window is compromised, resulting in issues like moisture accumulation, drafts, and even structural damage. One way to prevent problems caused by swelling sashes and frames is to limit water absorption. Before repairing the water-damaged timber, make sure to dry the sashes.
  • Wood decay and wet rot are two of the most common problems that affect wooden windows: It is crucial to protect timber windows from damage, as they are vulnerable to a variety of common problems such as decay and wet rot. Wood decay is caused by fungi that break down pieces of wood over time. This can weaken a window frame and potentially lead to structural failure beyond repair. Wet rot is also a concern, as this type of damage is often caused by moisture getting trapped in a window’s frame. To prevent problems like these, it is important to keep wood windows dry at all times, sweeping away any debris and avoiding contact with moisture.


The classic restoration methods

The goal of traditional wood window restoration is to fix degradation caused by normal wear and tear.

When it comes to repairing a casement or sash window, there are a number of important steps that need to be taken in order to ensure that the window functions properly and looks great.

Some of these steps include freeing jammed casements or sashes, removing build-ups of paint that interfere with their operation, replacing broken sash cords, lubricating pulleys and hinges, replacing broken glass and defective putty, and cleaning from paint and lubricating ironmongery.

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Additionally, it may also be necessary to replace missing or broken items such as handlebars, hinges, locks, or fasteners. With careful attention to detail at every stage of the process, your casement or sash windows will look and work like new ones in no time!

Open joints are one of the main causes of decay in original box sash windows. These loose spaces allow moisture to enter, which can cause the wood to rot and break down over time.

In order to prevent this type of damage and protect your work from decay, it is important to properly secure your joints. This can be done by cramping, glueing, wedging, and pinning.

Ultimately, regardless of the method you choose, it is vital that you take the time to tightly close all open joints in your work in order to ensure long-lasting durability.

Traditional materials

As we mentioned at the beginning of this article, some sash window specialists work only with traditional materials, some with modern, and some just mix them to achieve better results.

Materials commonly used in sash window restoration include timber, glues, putty, and sealants. It is critical to understand how to utilize various materials effectively in order to get the finest results in restoring period property.

Traditional Glazing Putty – linseed-based putty

For centuries, the traditional linseed-based putty has been used to secure the heavy glazing bars in wooden windows.

Originally developed by artisans working in medieval Europe, this putty is made from natural ingredients like linseed oil, limestone powder, and animal gelatin, which give it its unique flexibility and strength.

Linseed-based putty is inexpensive, costing less than £5 per kg, and widely available at most building supply stores.

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This time-tested putty has stood the test of time because it adheres well to wood, keeping the heavy glass panes securely in place even in strong winds. Additionally, the linseed-based putty is capable of forming a tight seal around each pane of glass to ensure that moisture and air do not seep into your home.

Overall, this versatile and durable material continues to be a popular choice for those who want their windows to look beautiful and perform flawlessly year after year.

Paint for wooden windows

Lead-based paints have long been a popular choice for painting timber and metal windows. Although, new technology has provided different types of paint specifically made for various materials and uses.

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Ultimately, choosing the right paint can help ensure that your windows not only look beautiful now but continue to look great well into the future.

What is the best type of wood to use when repairing windows?

When it comes to repairing or replacing damaged wood, it is important to choose a material that is both durable and stable.

One such option is the heartwood of trees like Scots pine and Douglas fir, both of which are known for their resistance to decay and other harsh conditions.

Additionally, chemically-modified softwoods, such as acetylated wood (Accoya, Tricoya), maybe a good choice for those looking for increased durability in their wood products.

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