Anatomy of a Sash Window

There can be different variations of sash windows, from the classic sliding sash window to the Venetian but they all house the fundamental parts which makes the window function:

 

1. Box Frame

The box frame is the sturdy timber casing which contains the sashes. This is what provides the stability and strength for the sashes to glide up and down the tracks.

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2. Top Rail

This is the upper horizontal part of the sash. Provides structure and support for the glass panes and overall sturdiness of the window.

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3. Parting Bead

This is a thin strip of wood that separates the two sashes, allowing them to glide past each other without catching.

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4. Staff Bead

This thin strip of wood holds the lower sash in place, while also contributing to minimising draughts by creating a seal.

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5. Sash Cord

A strong, yet flexible cord that attaches weights to the sash so that they can move up and down in a balanced manner.

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6. Weights

Contained within the weight pocket, weights help to counterbalance the sashes so that when moving up and down they stay in place with no additional support. Without the weights, the sashes could slam shut.

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7. Weight Pocket

This is a section within the box that houses the weights.

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8. Meeting Rail

This is the middle of the window where the bottom of the top sash and the top of the bottom sash meet when closed. This creates a seal to secure the window from draughts.

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9. Pulley Wheel

Housed in the box, this guides the sash cord preventing snags and allowing the sashes to move smoothly.

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10. Glazing Bar

This is a strip of wood (sometimes metal) which holds the individual panes of glass in the sash. These can come in different combinations to suit different tastes and properties.

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11. Bottom Rail

Like the top rail, only this is for the lower portion of the sash.

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12. Stile

These are the vertical sides of the sash, completing the framework of the sash along with the top and bottom rails.

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13. Sill

This integral part of the framework of the box protects the window from the elements and adds to the aesthetic appeal and charm.

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14. Mortise and Tenon Joint

Favoured for windows due to being the strongest and simplest way to join two pieces of wood at 90 degrees. Consisting of two sections - the mortise hole and the tenon tongue - this join requires expert craftsmanship due to the precision needed to ensure its longevity and tensile strength.