A window frame is the surround that holds the glass in place, keeps the weather out and fixes the whole unit into the wall of your house. It sounds simple, but a frame is made up of several parts working together, and the material it is made from changes how warm, secure and long lasting the window will be.
If you are thinking about new windows, or just trying to work out why the old ones are letting in a draught, it helps to know what you are actually looking at. Here is the plain version.
What a window frame does
The frame has three big jobs. It supports the glass so it does not sag or crack. It seals the gap between your home and the outside so heat stays in and rain stays out. And it gives the window somewhere to open from, whether that is on a hinge or a slide.
Get the frame right and the window feels solid, opens smoothly and keeps the room cosy. Get it wrong, or let it age past its best, and you notice cold spots, condensation and that tired look from the street.
The main parts of a window frame
Once you know the names, the whole thing makes a lot more sense.
The outer frame
This is the fixed part that is screwed into the wall opening. Everything else sits inside it. The outer frame carries the weight of the window and is what gets sealed against the brickwork with a bead of silicone.
The sash
The sash is the moving part that holds the glass and opens. On a casement window it swings out on hinges. On a sash window it slides up and down. A fixed pane that does not open has no sash as such, just glass held directly in the frame.
The mullion and transom
A mullion is a vertical bar that splits the frame into sections, so you can have two or three windows side by side in one opening. A transom is the same idea running horizontally. These add strength and let you mix an opening pane with a fixed one.
The cill
The cill (sometimes spelled sill) is the bottom part of the frame that slopes slightly outward. That slope is deliberate. It throws rainwater away from the wall rather than letting it pool and soak in. A good cill is one of the quiet reasons a window lasts.
The beading
Beading is the strip that clips in to hold the glass unit securely in the frame. On modern windows it sits on the inside, which makes the glass much harder to prise out from the street and keeps things more secure.
Seals and gaskets
Rubber gaskets and weather seals run around the frame and sash. They are what actually stop draughts and rain getting past. When these perish with age, a window that looks fine can still feel cold, and that is often a repair rather than a replacement job.
What window frames are made from
The material is the biggest single choice you will make, so it is worth understanding the trade-offs.
uPVC
uPVC is the most common choice across York and North Yorkshire, and for good reason. It is warm, low maintenance, keeps its colour and is the most affordable option for most homes. Modern uPVC comes in a wide range of colours and woodgrain finishes, so it is not just white any more. Our uPVC window range covers most styles you are likely to want.
Aluminium
Aluminium frames are slim and very strong, which means more glass and less frame. That makes them a favourite for large panes, contemporary extensions and anywhere you want a clean, modern line. They are more expensive than uPVC but extremely durable. Take a look at our aluminium windows if a slimline look appeals.
Timber
Timber is the traditional choice, and in a conservation area or a period property it can be exactly right. It looks beautiful and can be repaired and repainted, but it needs regular upkeep to stay in good shape. Many owners of older York terraces choose it to keep the character of the street.
Composite
Composite frames combine materials, often a timber core with an aluminium outer skin, to get the warmth of wood with the low maintenance of metal. They sit at the premium end but perform very well.
Signs your window frame needs attention
- Draughts you can feel with your hand near the edges
- Condensation between the panes, which points to a failed seal
- Frames that are stiff, sticking or will not lock properly
- Rot or soft spots on timber, or cracking on old uPVC
- Damp or staining on the wall below the cill
Some of these are a straightforward repair. A perished gasket or a broken hinge does not always mean a new window. If you are not sure, our team handles window and door repairs across the area and will tell you honestly whether a fix will do.
FAQs
What is the difference between a window frame and a sash?
The frame is the whole surround, including the fixed outer part bolted into the wall. The sash is just the moving section that holds the glass and opens. A window can have several sashes or none at all if every pane is fixed.
Which window frame material lasts longest?
Aluminium is the most durable and can last decades with almost no upkeep. Good quality uPVC lasts a long time too, typically twenty years or more. Timber can last just as long but only if it is looked after with regular painting and care.
Can a window frame be repaired instead of replaced?
Often, yes. Draughts, stiff opening and misted glass can frequently be sorted by replacing seals, hinges or the glass unit rather than the whole frame. It is worth getting it looked at before assuming you need a full replacement.
What is a window cill for?
The cill is the sloped bottom of the frame. Its job is to shed rainwater away from the wall so it does not soak into the brickwork. A damaged or missing cill can lead to damp, so it is worth keeping an eye on.
Want to see the full range of frames, styles and finishes up close? Download our latest brochure, or ask us for a free quote and we will pop out for a look at your home.