Ask 9 out of 10 people on the street what 'External Rendering' is and they'll say something along the lines and to the effect of "applying sand and cement" to the outside walls of your house. And due to this lack of knowledge, therefore, when 9 out of 10 people see that the exterior of their homes are in need of repair, they assume exactly this - and find someone to apply sand and cement render to their walls. And then they get this painted.
Technology has advanced! It has been well known and established for quite some time that applying traditional Sand and Cement Render to the exterior of a building is a non-optimum and expensive mistake! Read more about the poor qualities of traditional render here and why you don't want it ...
There are many modern and technologically advanced materials and systems available on the market today for a wide number of specific applications and purposes. Below is a brief overview
Monocouche Rendering
Monocouche Render is a one coat, pre-mixed, cementitious, weather resistant, external decorative, through coloured render, suitable for most types of brick or blockwork. This is machine applied allowing for fast application with shorter programme periods, thereby reducing associated scaffolding and site costs. 
Monocouche is through-coloured microporous material which allows the substrate to breathe with no need for painting. This results in a lower-maintenance exterior surface which is more resitant to cracks and algae growth and the natural phenomon of lime bloom.
Monocouche Render is generally applied directly onto blockwork in New Build scenarios, being now well established as a far superior product to that of traditional sand and cement render. Monocouche Render is also used in refurbishement projects on top of existing substrates in addition with key- and base-coats.
The benefits are a fast application of a long-lasting durable weather-proof surface and literally transforming an old house into new.
External Coating
External Coating, also known as Troweltex and Trowelcoat, is a 'textured synthetic coating', generally acrylic 
based and a polymer modified thin-coat render (silicone composites are also available). Polymers are unique, high performance thermoplastic elastomers engineered for a wide spectrum of end uses - one of those being 'coatings'. Polymer is a non-toxic, tasteless, non-radioactive environmentally friendly waterproofing product, with high ventilating and hygroscopic performance.
As with Monocouche, Troweltex is best applied via machine projection both for fast application with shorter programme periods and quality of finish. Troweltex is also available in a wide range of colours, is durable, crack-resistent and maintenance free without the need for painting.