Choosing and understanding traditional windows
Sash windows or casement windows: what is the difference?
A sliding sash window opens by moving a glazed sash within the fixed frame, usually vertically in a Scottish sash and case window. A casement opens on hinges. Both can suit a building, but they differ in movement, appearance, maintenance and replacement specification.
| Feature | Sliding sash and case | Casement |
|---|---|---|
| Opening | Sashes slide within the case. Many traditional examples use cords, pulleys and weights. | A sash opens on hinges; the hinge position and direction vary by design. |
| Space | Normal sliding operation does not project a sash out into the room or beyond the elevation. | The opening leaf needs clearance in its direction of travel. |
| Ventilation | Where both sashes operate, upper and lower openings can be adjusted. | The opening angle controls ventilation; restrictors and hardware affect travel. |
| Maintenance | Timber, coatings, putty, cords or balances, beads and fasteners need appropriate care. | Timber or other frame materials, glazing seals, hinges and locking mechanisms need appropriate care. |
| Traditional appearance | Meeting rails, glazing bars and sash proportions contribute to the appearance of many Scottish period homes. | Hinged construction has a different visual pattern; it may be original to some properties. |
| Cost | Condition, dimensions, timber, pane pattern, mechanisms, glass and access affect repair or replacement cost. | Material, dimensions, glazing, hardware and installation scope affect cost. Compare equivalent specifications. |
Which is better for a period property?
Start with the windows already in the building. Original sash and case windows may be repairable even where cords, paint or individual timber sections have failed. Changing to a different opening style can alter the character of the elevation. For sensitive or listed properties, establish the relevant consent position before ordering alterations.
Are sash windows always draughty?
No. Wear, poor alignment and defective beads or seals can allow excessive air leakage. Appropriate repairs and draught proofing may improve comfort. Frame material and opening style alone do not determine the whole-window performance.
Should you replace a sash window with a casement?
Do not assume a change of style is necessary to resolve sticking, rattling or local decay. Compare repair, refurbishment and replacement against the condition of the actual window, the desired outcome and the building’s character. See our repair or replacement guide.
What should you compare in quotations?
Check the complete scope: work to the sash and outer frame, glass specification, repair or replacement, draught seals, finishing, access, making good and VAT. A price for a minor repair is not comparable with a new fully fitted window. Our repair cost guide explains the factors.
Related guides and services
- What is a window sash?
- How sash and case windows work
- Specialist sash window repairs
- New made-to-measure timber sash windows
- Browse all homeowner resources
Ask us to assess your existing windows before deciding which work is appropriate.