A trough vault is a vault over a rectangular plan whose four vault surfaces do not meet at a single point at the top, but touch along a straight line — a ridge. It sits between the cloister vault and the barrel vault: pull the surfaces of a cloister vault apart until a ridge forms, and you have a trough vault. In Dutch it is called a muldengewelf or wangewelf, in German a Muldengewölbe.
It can also be described as a barrel closed at each short end by a curved vault cheek, producing groins in the corners. The form appears in the Renaissance and Baroque and was later imitated as a plaster ceiling shape.
How to recognise it
- Over a rectangular room — over a square plan it would be a cloister vault again
- A straight ridge in the middle instead of one highest point
- Curved end surfaces at the short sides, rising towards the ridge
- Groins in the corners, where the long and end surfaces intersect
The difference from a barrel vault lies in those end surfaces: a barrel runs through for its full length and is closed off flat at the ends.
Application
The form is found in church chancels, chapels, gateways, cellars, corridors and formal rooms. In domestic architecture it is often no more than a ceiling shape in plaster on lath, under an ordinary roof structure.
Points to watch when repairing:
- Forces. A masonry vault thrusts outwards. Tie rods, heavy walls or buttresses take that thrust; never remove any of them without a structural assessment
- Cracks along the ridge usually indicate settlement or the loss of horizontal restraint, not surface damage. Establish the cause before repairing
- Materials. Repair with a mortar no harder than the original work; hard cement mortar makes cracking worse
- Plaster ceiling or real vault? Tap it or inspect from above. A plaster vault on lath is a finish and carries nothing
Related terms
- Vault
- Cloister vault
- Groin vault
- Barrel vault
- Transverse arch
- Wall arch
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