The term ‘perpend’ refers to the vertical joints between blocks or bricks that have been laid in a horizontal course to form a wall. Perpends are normally filled and sealed with mortar. The horizontal mortar joint in a wall construction is typically referred to as the bed joint.
Rather than being filled with mortar, perpends may also be left open to form weep holes or cavity ventilators. These provide openings that allow the drainage of moisture from within a wall construction and allow ventilating air to the back of a wall to help prevent mildew, dry rot and damp. They are generally formed by plastic inserts into the perpends, as these form a more uniform opening compared to simply leaving a void. See weep holes for more information.
A perpend stone is a long stone that extends between the inner and outer layers of a stone wall, tying the two layers together. The stone is ‘dressed’ at both ends.
The term ‘perpend’ may also be used more generally to refer to any brick or stone the longest dimension of which is perpendicular to the face of the wall.
 Related articles on Designing Buildings Wiki
Featured articles and news
OMA's plans for new arts centre to revitalise city's culture given planning approval.
Select committee criticises DEFRA for failing to take up its recommendations.
Nicola Sturgeon presents ICE's People's Choice Award to the Forth Road Bridge reopening.
Green paper published for consultation.
Mental health issues effect 80% of construction workers. Read our interview with the founders of a new wellbeing initiative.
Would Stephenson be disappointed by the lack of progress on the high speed transport of Hyperloop?
The immersive pop-up cinema experience that could revolutionise on-site health and safety training.
5 out of 10 filtering facepieces fail HSE tests.
Eleven Magazine announce the winner and runners-up in their Moontopia competition.
As January is the time for hitting the gym, Designing Buildings Wiki lists the best gym architecture in the world.
London is at the top of the list of global construction megacities, beating Dubai and Abu Dhabi.