Understanding Sash Window Terminology

Terminology

1. Sash Window: A window that consists of one or more movable panels, or “sashes,” that hold panes of glass. Sash windows are traditionally operated by a system of weights, cords, and pulleys, allowing the sashes to slide vertically or horizontally.

2. Sash: The sash is the movable panel within a window frame that holds the panes of glass in place. Sashes can be single-hung (one movable sash) or double-hung (two movable sashes).

3. Frame: The frame is the structural component that surrounds and supports the sash. It includes the head (top), jambs (sides), and sill (bottom). The frame is fixed in the window opening and provides the foundation for the sash to slide or tilt.

4. Glazing Bar (Muntin): A glazing bar, also known as a muntin, is a narrow strip that divides the glass panes within a sash. Traditionally, glazing bars were necessary for structural support of multiple small panes of glass; today, they often serve a decorative purpose.

5. Meeting Rail: The horizontal section of a sash where two sashes meet when the window is closed. In a double hung sash window, each sash has a meeting rail that overlaps when the window is shut, creating a seal and enhancing security.

6. Stile: The vertical components of a sash window. Each sash has two stiles, which are connected by horizontal rails. The stiles are responsible for the vertical stability of the sash.

7. Astragal: A decorative moulding that separates panes of glass within a sash. Unlike a glazing bar, an astragal is not always structural and may be used purely for decorative effect.

8. Sash Cord: A cord made from strong, durable material (traditionally cotton or synthetic fibre) that is connected to the sash and weight, running over pulleys. The sash cord allows the window to be raised and lowered smoothly.

9. Sash Pulley: A small, often brass or metal, wheel set into the frame that the sash cord runs over. The pulley reduces friction and wear on the sash cord, ensuring smooth operation of the window.

10. Sash Weight: A weight, typically made from cast iron or lead, that is housed within the window frame and counterbalances the sash. This allows the sash to remain open at any height. The weights are connected to the sashes via the sash cords.

11. Parting Bead: A slim strip of wood or plastic that runs vertically between the sashes in a double-hung window. The parting bead keeps the sashes from rubbing against each other, providing separation and guiding their movement.

12. Staff Bead: The staff bead, or stop bead, is the moulding that holds the bottom sash in place. It is usually removable, allowing access to the sash and frame for maintenance or repair.

13. Sash Horn: A projecting element at the base of the upper sash, often found in Victorian and Georgian designs. Originally introduced to add strength to the window, sash horns are now more of a decorative feature that reflects traditional craftsmanship.

14. Sash Catch or Fastener: A small metal device that secures the window when it is closed. The catch is often located on the meeting rail and can be latched or locked to prevent the window from opening.

15. Draught Excluder: A strip of material, such as brush pile or silicone, added to the frame or sash to prevent draughts from entering. Draught excluders are used to improve energy efficiency and prevent air leaks around the sashes.

16. Double Glazing Unit: A sealed unit made of two panes of glass separated by an air or gas-filled space, which provides improved insulation over single-glazed windows. Double glazing units are often used in modern sash window renovations to enhance thermal performance.

17. Mullion: A vertical element that separates two or more windows in a single frame. Mullions can be structural or purely decorative, and they are often used to create larger window configurations.

18. Sill: The horizontal, lower part of the frame that projects outward. The sill supports the sash and helps drain water away from the window. It is a crucial component for preventing water ingress and ensuring longevity.

19. Sash Window Lock: A security feature installed on the meeting rail or sash frame. Sash locks prevent the sashes from being opened from the outside and are often required for insurance compliance.

20. Trickle Vent: A small ventilation opening, typically found at the top of the frame, allowing fresh air to enter the room while the window remains closed. Trickle vents help improve indoor air quality without compromising security.

21. Abutment: The part of the sash window frame that connects and provides structural support where the sashes meet.

22. Angle Bead: A decorative moulding that is placed at the junction of two surfaces to form a sharp corner. Angle beads are often used to finish the internal or external edges of window reveals.

23. Box Frame: The hollow frame that surrounds the sash window, often housing the weights and pulleys. The box frame allows the sashes to slide vertically.

24. Resin Fill: A two-part epoxy resin used to repair or replace decayed timber sections of sash windows. It is mixed and applied to damaged areas, providing a solid and durable surface that can be sanded and painted like wood.

25. Sash Bolt: A small, spring-loaded bolt installed on the sash, usually for additional security. Sash bolts are placed at the meeting rail or into the frame, preventing the sash from being opened.

26. Keep: The metal part that a sash lock or fastener hooks into. Keeps are usually fixed to the meeting rail of the lower sash or to the frame.

27. Hinge: Hinges are used in tilt or inward opening sashes. They are metal hardware pieces that allow the sash to pivot, making cleaning and maintenance easier.

28. Rebate: A step-shaped cut or groove in the timber frame that allows another component to sit flush against it. Rebates are often used to secure glass panes or fit mouldings.

29. Stepped Sill: A sill designed with steps to create better drainage and ensure that water runs off without seeping into the window frame. This type of sill is especially common in historic or listed buildings.

30. Cill (Subcill): An alternative spelling for "sill," referring specifically to the lower horizontal part of the frame. A subcill is an additional piece fitted under the main cill for added protection against weathering.

31. Ovolo Moulding: A decorative profile with a convex curve, often found on the inner or outer edges of sash windows. Ovolo mouldings add a traditional appearance and can be found around the glazing or on the frame.

32. Weather Bar: A small timber or metal strip located on the outside of the bottom sash or cill, designed to deflect water away from the frame.

33. Riser Block: A block used to raise or adjust the height of the window furniture such as handles or catches. Riser blocks can be made of timber, plastic, or metal.

34. Pulley Stile: The section of the box frame that houses the pulleys. It is often a removable piece, allowing access to the cords and weights for maintenance.

35. Pocket Piece: A removable section of the box frame, often on the jamb, providing access to the sash weights. The pocket piece can be taken out to adjust or replace the sash weights without dismantling the frame.

36. Rubbing Strip: A small strip, often plastic or timber, fitted between the sashes to reduce friction and ensure smooth sliding of the sashes.

37. Bronze/Brass Ironmongery: Refers to the use of bronze or brass materials in the hardware components such as pulleys, sash catches, handles, and stops. These metals are chosen for their durability and aesthetic appeal.

38. Anti lift Device: A small piece of hardware, often a metal pin or strip, designed to prevent the sash from being lifted out of the frame.

39. Stop Bead Adjuster: An adjustable screw or fitting on the stop bead that allows fine-tuning of the sash’s movement within the frame. This is particularly useful for maintaining a smooth slide while minimizing draughts.

40. Spirit Varnish: A traditional type of varnish, made using alcohol as a solvent, often used to protect and finish timber sashes.

41. Hock-end (or Haunch) Joint: A traditional joint used in the construction of sash windows, where the ends of the stiles or rails are cut to form a dovetail or tenon-like shape. This type of joint provides strength and stability to the sash.

42. Gasket: A flexible seal, often rubber or silicone, placed between the glass and the timber frame or sash to create a watertight seal.

43. Spiral Balance: A modern alternative to the traditional weight and pulley system, spiral balances are spring-loaded mechanisms that counterbalance the weight of the sash, allowing for smooth movement without the need for weights.

44. Locking Peg: A small peg used to lock or secure the sash in a partially open position. Locking pegs can be inserted into pre drilled holes in the sash frame.

45. Tilt Latch: A latch that allows the sash to tilt inward or outward for cleaning. These are often used in modern sash windows or on windows with a tilt-and-turn feature.

46. Finger Pull: A small handle or grip attached to the lower rail of the bottom sash, allowing for easy lifting of the sash. Finger pulls can be made of brass, chrome, or wood.

47. Slip Bead: A removable bead that holds the sash in place while allowing easy access for repairs or glass replacement. Slip beads are often used in combination with sash stops.

48. Sash Lift: A metal handle, usually installed on the bottom rail of the lower sash, designed for lifting and closing the sash. Sash lifts can be decorative or plain.

49. Catch Plate: The metal plate attached to the frame that the sash fastener hooks into, ensuring a secure closure.

50. Polished Nickel, Chrome, or Satin Hardware: Refers to various finishes available for the metal components of sash windows, such as pulleys, fasteners, and sash lifts. Different finishes provide distinct aesthetic options to match modern or traditional interiors.

51. Epoxy Putty: A versatile material used for filling voids or rebuilding decayed sections of timber. Epoxy putty is mixed and shaped before it hardens, offering a durable and sandable surface.

52. Linseed Oil Putty: A traditional glazing putty made from linseed oil and chalk, used to bed glass panes in timber frames. It forms a long lasting and flexible seal once hardened.

53. Marine grade Varnish: A high-durability varnish used for protecting timber sashes exposed to harsh weather conditions. It is highly resistant to moisture and UV damage.

54. Lead Weights: Used in traditional sash windows to counterbalance the weight of the sashes. Lead weights are housed within the box frame and connected to the sashes by cords.

55. Timber Dowel Pins: Small wooden dowels used for joining timber components together. Dowels provide a strong, invisible bond between the sash parts.

56. Concealed Fixings: Fixings or screws that are hidden from view, providing a clean appearance. Concealed fixings are often used in high-end sash window installations.