What is a toog?
Toog (Dutch term for a shallow arch) is a slight but clearly curved shape in a structure, especially above a window or door opening. A window or door with such a curved head is called getoogd in Dutch, so you get an arched frame, an arched head or an arched window. The word is related to the old Dutch verb togen or tijgen, meaning to pull.
Meanings
- Curved shape: a shallow arch, often a segmental arch, over an opening in brickwork. This is the most common meaning in building.
- Camber: a very slight upward curve built into a beam or floor slab to compensate for deflection under load.
- Tuff: in older sources, a lower-quality type of tuff used to make trass for mortar.
- Bar: in Flanders, the toog is the bar counter in a café.
The arched opening in practice
- Facades: arched windows and doors are common especially in 19th and early 20th century houses, topped with a soldier course or rowlock course following the curve.
- Frames: an arched frame has a curved head that follows the line of the arch. The sashes and glass must follow the curve too.
- Structure: the arch carries the load of the brickwork above in compression to the piers beside the opening. With a shallow arch, the horizontal thrust is relatively large.
Tips for renovation
- Replacing an arched frame with a straight one changes the look of a facade dramatically. For listed buildings and conservation areas, permission is often required; check with the local authority.
- Have a new arched frame made to a template of the existing arch: old arches are rarely exactly the same.
- Cracks in the arch or sagging bricks point to a load-bearing problem. Have this assessed before replacing frames.
Related terms
- Segmental arch
- Soldier course
- Lintel
- Window frame
- Horizontal thrust
- Listed building (monument)
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