Lime Render System

When it comes to traditional mortars, washes, plaster and renders, lime is the key ingredient that makes it work. For many centuries, people have been using various kinds of lime and formulated it in many ways to prepare and use it. In the simplest procedure, lime is prepared by heating it in a kiln to remove CO2, which is later reabsorbed while the mortar is curing.  

If the generated power used in heating the lime is renewable, it makes the lime processing carbon neutral. In recent years, there has been a renaissance in the creation of mortar through traditional methods, which is often carried out by combining aggregate, quick lime and water to produce a hot mixed lime mortar. 

Not all limes are created equal. Some have impurities that make them similar to cement but not as strong as cement. These mortars are still beneficial in places with harsh weather conditions but are considered less penetrable and less environmentally friendly.

Lime Render    

A lot of people don’t realise that when it comes to rendering and plastering your properties, lime plaster is a good option to take. The kinds that are mostly offered by merchants are often made with gypsum or cement. Lime is a bit distinctive. 

In the UK, lime mortars and plasters were the only available option for houses before the arrival of World War 2. The trend for mass production came during the war and after it ended, the need to standardise and prefabricate construction materials were pushed by the builders. By then, concrete blocks and plasterboard became the norm, while gypsum-based plasters and cement-based plasters and mortars became the top choice in building a house. But the construction world has now realised that doing away with lime was such a loss.  

External Lime Render    

Part of the reason why lime plaster was revived is due to the fact that it ‘breathes’. It means that moisture or water vapour in the environment can be taken in and let out by lime plasters. This is the great advantage of lime. It lets moisture move through the structure of the property from inside out, but this doesn’t mean it simply lets the weather go in. It simply means it creates a path for the moisture to be released. Gypsum and cement, on the other hand, does not work the same. They don’t allow moisture to pass through. Additionally, gypsum will disintegrate over time. On top of that, the lime render system can benefit homeowners in many ways:

• For homes. Lime plaster, if used internally, will act as a moisture shield. If humidity is high, it absorbs moisture and releases it when the air becomes dry. This property of lime plaster is the key to prevent surface condensation, which is often the reason why mould appears. This does not cancel out the need for proper ventilation and insulation but it works hand in hand to manage moisture inside your home. 
• For buildings with solid walls. Did you know that 30% of the houses in the UK are built using solid masonry construction? These homes need to release moisture to the environment as they do not have cavities to keep moisture from getting on the inside. We need to lead moisture the right way and that is out. The lime render system is capable of allowing our walls to equalise, keeping moisture from getting in but allowing moisture from inside to escape.  
• For newly built properties. The breathability of lime allows buildings or homes to dry out thoroughly after construction and provides a channel for water to get into the walls and out of it. For instance, a burst pipe or leaky window can increase the moisture indoors and one way to let this moisture out is through the natural lime render. 

The PURACALCE lime range is a line of environmentally friendly products, made with hydrated lime, an extremely natural raw material used since ancient times: complete cycles of products with high porosity and breath-ability which, thanks to their temperature and humidity control function, create a healthier and more comfortable environment.

Bio limes offer high-quality solutions to restore walls with moisture problems and to make any housing reality healthier and more liveable, whether newly constructed, renovated or restored buildings.

Use either KB13 or K1710 as the lime base render with S605 finish coat

KB13 is a lime-based base render for interiors and exteriors.  Used on brick & concrete walls.  KB13 will allow breath-ability of the substrate for use when moisture is not a problem

Use as a slurry coat and a base coat

• 1 bag = 4-5m2 as a slurry coat @ 2-3mm thick covering a minimum of 50% of the wall
• 1 bag = 1m2 @ 20mm thick

K1710 is a fibre reinforced lime-based render made from pure nano-lime for interiors and exteriors.  Used on brick, concrete block, rock, stone & difficult substrates. K1710 with characteristics of extremely high purity and fineness allows you to obtain a workable mix, with a reduced tendency to the formation of efflorescence and excellent mechanical resistance, properties resulting from a rapid carbonation process of the product.

Use as a slurry coat and a base coat

• 1 bag = 4-5m2 as a slurry coat @ 2-3mm thick covering a minimum of 50% of the wall
• 1 bag = 1m2 @ 20mm thick

S605 is a lime-based finishing mortar made from PURE HYDRATED LIME, for finishing porous renovations.  To be applied as a finish coat to KB13 or K1710.  

• 1 bag = 5-6m2 @ 3-4mm thick with a fibreglass mesh embedded in the first pass.

Lime Render Mixer    

When mixing lime, a typical cement mixer can be used but for projects of a larger scale, a paddle mixer is advised. The mix is usually 1 part lime with 2.5 parts sand. The raw materials are always measured using a gauging bucket or box. Using a shovel to measure the ingredients is unacceptable since it will only give us inconsistent amounts. When combined inside drum mixers, lime mortars are susceptible to balling. The use of certain mixing methods can help reduce this. The following procedure can work well on your combination:

• Prepare an empty mixer
• Place 1 part sand
• Place 1 part lime
• Mix it with 1.5 parts sand
• Mix dry the raw materials for at least 5 minutes
• Slowly introduce water into the mixture after 5 minutes and continue adding water until your preferred consistency is reached. Do not drown the mixture with too much water.
• As soon as the preferred consistency is reached, mix it further for 20 minutes

In the beginning, the raw materials should be mixed dry but as the mixing time progresses, the render will become stickier. If you will add too much water to the mixture, the possibility of shrinkage will rise and the final strength of the lime render might be reduced. With this in mind, do not use it in conjunction with waterproofers and plasticisers. Upon application, make sure the walls are damp so you can decrease the effects of suction on the lime render.

Natural Lime Render    

When combined with animal hair or fibre, lime render and plaster tends to be more flexible compared to gypsum or cement plasters. This makes them more resilient against cracking which is something that is very suitable if your house moves along with the seasons, as many houses do. 

Cement-based plasters are very tough that it’s very difficult to take them out of the wall. If the wall is made of stone or brick, removing it might damage the wall itself. Natural lime render is softer than that. Although it is hard and resilient, it is not as hard as cement-based plasters. Removing it is not as difficult too. 

Lime Based Render

Let’s face it. Lime plaster walls look beautiful! Its matt finish, shade and texture give it an artistic appeal that simple appeals to the senses.

If you are worried that you have more lime-based render than you need, do not fret. You can use it anytime you will need it in the future. So nothing goes to waste, unlike gypsum and cement which is usually taken away through the skip. If the old lime plaster is removed, it can be reused by crushing and adding it to the new mix as an aggregate. As we have mentioned earlier, walls with lime plaster prevent your walls from building up moisture, condensation and cracking. That is why lime-based render is less wasteful than its counterparts.

If you live in Swindon and the surrounding areas and you are looking for a reliable, trusted and leading render and drylining supplier, get in touch with Amaroc on 0333 150 26 26 (web orders), 01793 23 29 30 (Swindon) or sales@amaroc.co.uk today! We offer the best brands and the widest array of choices for all your rendering needs. On top of that, you can get it at the best prices too! Talk to our team and we will be able to advise you of the best products that are best suited for your projects at hand.