EXTERNAL COATINGS AND RENDERINGS
Render and exterior coating systems are applied to the external walls of houses and garden/boundary walls as a smooth or textured finished surface. The primary goal of rendering is often to protect perishing or defective brickwork or simply to alter the appearance of the property.
Whether a property is rendered for cosmetic purposes or to seal damaged masonry there are no denying the many benefits of a rendering application such as improved thermal qualities, masonry protection against penetrating damp, weathering and also frost protection.
How is it done?
Traditional render is produced by mixing sand, cement and hydrated lime together with water and mortar plasticiser. Render is applied in two coats traditionally using a hawk and trowel but sometimes sprayed on under high pressure for larger jobs.
The first coat is called the ‘scratch coat’ which has the purpose of sealing the brickwork and creating a nice flat surface with plenty of key for the next coat.
The second coat is called the ‘top coat’, after the scratch coat is left to settle and dry for 24 hours (depending on weather conditions) the top coat is then applied and ‘ruled off’ using a straight edge, the render is then either ‘rubbed up’ with a float and sponge to take away any high points and leave a smooth finish or a texture is applied using spray guns or by throwing pebbles at the wet render, the typical names of these textured finishes are pebble dashing, roughcasting and tyrolean.
A modern version of rendering is referred to as colour render or K-rend. This type of render is a silicone based product which offers more durability and better insulation qualities. The colour render (as its name suggests) comes in a variety of colours and finished textures.
Another type of modern day rendering system which is used to overcome the issues of poorly insulated homes from the exterior is called the insulated render system.
This is where panels of highly insulated sheeting are fixed to the properties exterior to form a new outer layer, the corners and angles are beaded to create sharp edges and then the render is applied to the sheeting leaving a typical rendered finish but with a much higher level of thermal qualities.
For more information on the varieties of rendering and products available, or if you think your property requires further insulation or masonry protection contact Damp Proofing Solutions to arrange an appointment with an expert surveyor.