External render can be the ideal introduction to a property renovation project. If the external elevations are dilapidated or the external aesthetic offer no ornate features, when a property has been extended or altered external render can be applied to really brighten and renew the overall appearance of the building. Especially given the wide range of European renders now available, the days of sand and cement render followed by paint are gone as a wide range of polymer modified through coloured renders and multi layer renders are available.
One coat Decorative through coloured renders
These decorative renders; monocouche, through coloured, scratch renders are all factory batched and BBA approved. We don’t mix our own or buy in poor products we only use the best quality products and apply them as per their technical specifications with care, speed and skill.
Through coloured renders are available in a selection of colours, each manufacturer has a slightly different variation available but these usually consist of standard colours and special colours.
The standard colours are those used on most projects and due to this are manufactured and stocked continually, special colours come with a premium as these are usually only manufactured to order and have a longer call off time.
One coat through coloured decorative render is a Hydraulic Lime Mortar, each manufacturer has their own specific mix but generally the composition of these renders comprise Cement, Lime, Sand, Mineral Pigments and specific admixtures and arrive in powder form. After we have carried out preparation and enabling works when ready to apply we add clean water and mix on site, the render is then applied to the wall. To ensure we can apply the render in a timely and uniform manner we have our own mobile factory which we carry a render mixer and pump and all necessary tools, when mixing we spray the render onto the wall and continue the process until the render is applied to the correct thickness. One coat renders are ideally suited to traditional masonry construction properties, be that existing facing brick or new build with blockwork.
As a minimum the render is applied 15mm thick, some manufactures state a 10mm coat can be used but to ensure an adequate and even application we only use 15mm thick beads and apply the render to this thickness which ensures a high quality finish and colour consistency. The render once hydrated but not fully is scraped back with a scraping tool which leaves a flat surface with a slightly grainy textured finish.
We use upvc angle and stop beads to all edge details as these come coloured and can be ordered in the best colour to match the specified render. The render is applied with mesh reinforcement to all stress points as per manufactures and specific project detailing. The mesh ensures at positions over doors and windows where movement is likely that the render is heavily reinforced to avoid cracking.
The weather conditions for applying render are set out by manufacturers and are generally 5 deg C and above upto 30 deg C and in dry conditions. If applying in temperatures above 30C then special consideration and measures are to be taken to ensure the render hydrates correctly. Applying render in England we have extensive experience of rendering in all different seasons and weather types and will only apply when the weather is suitable.
Flexible multi layer Silicone and Acrylic renders
There is another coloured render type available, this is a flexible silicone or acrylic render which is again available from leading manufacturers and installed by us.
This render is ideally suited to modern methods of construction although this can easily be applied to traditional masonry. The multi layer application and synthetic materials make for a very flexible and durable render finish which are available in practically any colour mix required.
Each manufacturers material varies considerably with some having patent and exclusive cement free synthetic products. But all systems have a similar build up which comprise a 6mm mesh reinforced base coat, a primer followed by a textured Acrylic or Silicone topcoat. This system has a build up of 8mm nominally although can be thicker and if applied to masonry would require an additional 8 to 10mm leveling coat to ensure and even surface. Flexible renders can be applied to External Wall insulation slabs which when applied this way always come as a full system including the insulation, insulation fixings and ancillaries and the render products, the render applied in the 6mm mesh base coat, primer and topcoat directly to the insulation slab. Flexible renders are ideal for timber frame or modern method of construction such as SFS and make an excellent alternative to cladding, the render systems would be applied in this method directly to a render carrier board or insulation slab and would consist of the 6mm mesh reinforced base coat, primer and topcoat.
The base coat is usually factory batched, bagged and mixed on site although some patented manufacturers sell product in pre mixed tubs which simply require a mix with a paddle mixed to activate. All systems are applied by hand trowel in two coats, the first a 3 millimetre coat which the plastic reinforcing mesh is then embedded into, once the mesh is in place this is then covered with a second coat of the same product 3mm thick which is trowelled flat and level ready for receiving the topcoat. Once the mesh coat is dry before applying the topcoat a primer coat is generally required with unifies the base coat into a similar colour as the topcoat to ensure no show through and equal adhesion.
The topcoat is an Acrylic or Silicone based synthetic textured finish coat which resembles a thick paint and applied like a skim coat of plaster, the topcoat comes with varying grain sizes from 1mm to 6mm with the main tendency to be specifed as a 1.5mm grain as this leaves a relatively smooth finish but with enough aggregate to ensure any slight surface deviations are not seen. The topcoat is applied by hand trowel in very similar technique as skimming although as with all stages applicator experience and skill are essential to ensure good results are achieved.
We are available for all projects in the Hull & Yorkshire region as well as mainland UK based coverage and can bring our experience to your project to ensure the right finish first time, call us or email for a quote we will be happy to hear from you.