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
Read about the launch event for our major new report about the worrying and widening construction knowledge gap.
We've analysed 6 million pieces of data to reveal that the knowledge framework underpinning the construction industry is no longer fit for purpose.
The theme for BSRIA's 2017 Briefing is 'Solutions to Tomorrow’s Challenges in Today’s Buildings'.
Dealing more than 1,700 consultations was just one of last year’s tasks for the Gardens Trust.
Read about the history behind one of California's most iconic buildings, the Griffith Observatory.
ICE examine just how close we are to providing subsidy-free low carbon electricity.
Have a look at MAD Architects' design proposal for renovating Montparnasse Tower into a concave mirror.
This article examines the legal issues behind off-site goods and materials.
Read about how technology is changing the real estate industry.
BRE Global introduce the first registration scheme for Suitably Qualified Security Specialists.
An introductory article to the different types of building foundations.
This unique Brutalist-era car park just off Oxford Street is soon to be demolished.