The words "casing", "lining", "architrave" and "trim" get thrown around a lot when people talk about doors, and it is easy to muddle them up. Here is a simple guide to door casing and the pieces around it, so you know what each part is and how they fit together.
Door casing is the woodwork that surrounds a door opening and gives the door something to hang from and close against. In everyday use, "door casing" often covers the whole frame plus the decorative trim around it, though strictly speaking those are two separate parts. Once you can name them, the whole thing makes a lot more sense.
The parts around a door
There are three main pieces to know, working from the inside of the opening outwards:
- The lining (or frame). This is the timber that lines the sides and top of the opening. It is what the hinges screw into and what the door shuts against. On an internal door this is usually a plain three-sided frame with no sill at the bottom.
- The door stop. A thin strip fixed to the inside of the lining that the door closes against, so it cannot swing straight through. It stops the door in the right place and helps block draughts and sound.
- The architrave. The decorative moulding that runs around the front of the opening where the lining meets the wall. Its job is partly to look neat and partly to hide the join and any gaps between the frame and the plaster.
Put simply, the lining does the structural work, the door stop positions the door, and the architrave is the tidy border you actually see.
Casing versus architrave versus trim
This is where the words blur, so it is worth pinning down:
- Casing is often used to mean the frame and trim together, the whole assembly around the door.
- Architrave is specifically the moulded border on the face of the wall around the opening.
- Trim is a catch-all word for any finishing woodwork, which includes architrave, skirting and beading.
So all architrave is trim, but not all trim is architrave. And when a joiner talks about "casing up" a door, they usually mean fitting the frame and the surrounding mouldings.
How the pieces fit together
On a typical internal door, the order of work goes something like this. The lining is fixed into the opening first, checked for level and square. The door is then hung on its hinges within the lining so it swings and closes properly. The door stop is fixed to suit the closed position of the door. Finally the architrave is mitred at the corners, where the two lengths meet at a neat 45-degree angle, and fixed around the front to cover the joins and finish the look.
Getting the mitres tight and the architrave sitting flat is what separates a neat job from a scrappy one. Small gaps can be filled and painted, but a well-cut mitre needs very little making good.
Architrave styles
Architrave is where you can add a bit of character, and the style you pick sets the tone of a room:
- Ogee. A classic S-shaped curve, common in period and traditional homes.
- Chamfered. A simple angled edge, clean and understated.
- Bullnose (rounded). A soft, rounded edge that suits modern interiors.
- Square edge. Plain and contemporary, with crisp lines.
For a period home in York, a heavier moulded architrave often suits the age of the property, while a newer house might carry a simpler square-edge profile better. Matching the architrave to the skirting in the same room keeps everything looking of a piece.
A note on external doors
Everything above applies to internal doors. External doors are a bit different, because the frame has to keep out weather and take a secure lock, and it usually includes a weatherproof sill at the bottom. If you are replacing a front or back door, the frame is part of the finished unit rather than something built up on site, which is worth knowing when you compare a composite door or a uPVC door. The decorative trim inside still gets finished with architrave in the same way.
FAQs
What is the difference between door casing and architrave?
Door casing usually refers to the whole assembly around a door, the lining that the door hangs from plus the surrounding trim. Architrave is specifically the decorative moulding on the face of the wall around the opening. So architrave is one part of the wider casing.
What is the frame of a door called?
On an internal door it is usually called the lining or the door frame. It is the timber that lines the sides and top of the opening, holds the hinges and gives the door something to close against. External doors have a heavier weatherproof frame instead.
What does architrave do?
Architrave finishes the edge of a door opening. It hides the join between the frame and the plaster, covers any small gaps, and gives the doorway a neat, decorative border. It also sets the style of the doorway, from traditional ogee to plain square edge.
Can I change just the architrave without replacing the door?
Yes. Architrave is fixed to the face of the wall and can be carefully removed and replaced without touching the door or its frame. It is a common way to update the look of a doorway, especially when matching new skirting in a room.
Planning a new door to go with that fresh trim? Download our latest brochure to see the styles, or request a free quote and we will pop out for a look across York and North Yorkshire.