What is ashlar detailing? - from stone to plasterwork
The word ‘ashlar’ has come to have two different meanings: ashlar stonework and ashlar plasterwork. Ashlar plasterwork is when render is used to imitate the look of ashlar stonework. Ashlar bead (see below) is the modern way to achieve this neat banding detail in plaster or render.
Ashlar stonework became popular in the Georgian period, when designers were influenced by classical Greek design. Think of the finely dressed square cut stone detail typical of Bath facades, with cut parallel lines forming details over the façade. Some of the town houses of Knightsbridge and Mayfair areas of central London are also great early examples.
The problem with ashlar stonework is that is was incredibly expensive, yet in demand to reflect the wealth and status of the new middle class.
Because ashlar stone was expensive and in demand, builders developed a technique of drawing and cutting lines into exterior plaster when it was not yet set, so it looked like the ashlar stonework. They emulated the quoin and banding details to achieve the same finished look more cheaply. This ashlar renderwork remained common until the late 1800s.
“John Nash used detailed render extensively in the early 19th century for his terraces in London, Brighton, Hastings, Southsea and Torquay as well as his Gothic and Italianate villas in Malvern, Leamington and Harrogate. Perhaps the finest example was his development of Regents Park, arguably his greatest work.” (from BuildingConservation.com)
Traditional ashlar detailing in render
Traditionally, there are 2 ways of creating the ashlar detailing in render:
- Cutting grooves into unset render with a tool, called a jointer, or marking with a roller
- Pressing oiled moulded battens into the first coat of render, rendering up to the battens with a second coat and removing when dry.
Designers and architects still use ashlar banding in render today, either to emulate Georgian details, or to add crisp lines to a façade.
It is still an option to tool cut ashlar detail into modern renders. The benefits of modern render are that it has greater durability and is easier to maintain due to various additives that often includes silicone.
Tool cuts can either be made into a through-coloured monocouche render (such as ProRend Colour), or into a thicker basecoat which then has a thin coat render applied as a second coat. The render can then be painted or left natural.
A great modern alternative to cutting is ashlar bead – a moulded plastic strip that remains in the render. ProBead ashlar bead makes clean straight lines and a neat 25mm detail. A cost effective alternative to manual detailing, using ashlar bead greatly reduces labour time.
Ashlar bead can be cut and fixed to the substrate accurately, giving a precise detailed finish to the rendered façade. For this reason, ashlar bead suits modern design details or a modern interpretation of Georgian detailing.
ProBead ashlar detail beads are available in 18 colours, are easy to cut and fit, and have fast delivery to site. There are many finishing options for the design of the façade, as the ashlar bead colour can match or contrast with the render colour. It can also be painted over easily to change or refresh at a later date.