What is the difference between Sash Windows and Sash and Case Windows?
In Scotland, the term sash and case is the traditional name for what is elsewhere called a “sliding sash window.” It refers specifically to the construction: the sash is the moving frame that holds the glass, and the case is the heavy timber box built into the wall that houses the weights and pulleys used to counterbalance the window.
Do I need planning permission to replace sash windows in Scotland?
It depends on your property’s status.
Permitted Development: For most standard homes, you can replace windows without permission if the style remains identical.
Conservation Areas: You often need permission if the window is on a “principal elevation” (front-facing). As of May 2024, cities like Edinburgh have introduced “Prior Approval” to streamline this.
Listed Buildings: You must obtain Listed Building Consent. Installing uPVC in a listed building is usually prohibited; timber is the standard requirement.
How much do new timber sliding sash windows cost in Scotland (2025)?
There are a lot of variables that determine the cost of a replacement timber sliding and sash and case window. Contact us for more details.
Can I upgrade my existing single-glazed sashes to double glazing?
Yes, this is a popular “middle path” in Scotland known as retrofitting. Instead of replacing the entire case (the box in the wall), we can manufacture new timber sashes containing heritage slimline double glazed units that fit into your original frames. This is often 40-60% cheaper than a full replacement and is frequently accepted by planning officers.
What are the benefits of timber over uPVC for sash windows?
While uPVC is cheaper, timber is often preferred in Scotland for three reasons:
Longevity: Well-maintained timber can last 60–100 years, whereas uPVC usually needs replacing every 20–30 years.
Property Value: Original-style timber windows significantly boost the “kerb appeal” and resale value of traditional Scottish tenements and cottages.
Sustainability: Sustainably sourced timber (like FSC-certified wood) is a carbon-neutral material compared to plastic.
What is the “Simplex” or “Easy Clean” system?
This is a uniquely Scottish feature essential for tenement flats. The Simplex system allows the bottom sash to unhook from its cords and swing inward like a door. This allows you to clean the outside glass from safely inside your room—a legal requirement for windows on the first floor or higher in many Scottish building regulations.
How often do timber sash windows need maintenance?
To protect against the Scottish climate, you should:
Repaint: Every 3 to 5 years using microporous paint (which allows the wood to “breathe”).
Lubricate: Apply a little candle wax or silicone spray to the pulley wheels once a year.
Check Sand Mastic: Inspect the “sand mastic” (the traditional seal between the window and the stone) every few years for cracks.
Are traditional timber sash windows secure?
Modern timber sash windows are very secure. Unlike the simple “fitch fasteners” of the past, new versions come with keyed locks, sash restrictors (which allow the window to open slightly for ventilation but not enough for someone to enter), and even smart sensors.
How can I tell if my windows need repair or a full replacement?
The Penknife Test: If you suspect rot in the sill, try to push a penknife into the wood. If it sinks in easily, there is significant rot.
Most sash windows in Scotland can be refurbished even if they look bad. You only need a full replacement if the outer case (the box) is structurally compromised. If only the moving sashes are rotten, they can be replaced individually.
Will new sash windows actually reduce my energy bills?
Yes. Traditional single-glazed windows are a major source of heat loss. Upgrading to double-glazed timber sashes with modern draught-proofing (brushes and seals) can reduce heat loss through the window by up to 70%. Homeowners in Scotland typically report a noticeable reduction in “window whistling” and a significant drop in annual heating costs.
See more here on our sash and case window repairs faq.