Those looking to install a Heritage Lime Render system are generally working with older properties that require high levels of breathability and flexibility. Lime is very porous and so it absorbs and releases humidity, allowing for a level of moisture regulation that is extremely important for ensuring structural integrity.
For heritage properties, it’s essential to use the right materials so as not to cause long-term damage; we’ve written before about inappropriate materials on the wrong substrate and the consequences – read the post here.
Our Heritage Lime Render system is highly natural and complements older buildings that would have previously been constructed using natural building technologies. So without further ado, here is how to install a Heritage Lime Render system…
Preparing the Substrate for Heritage Lime Render
Substrate preparation is a key element of any rendering project, but it’s especially important for heritage restoration projects. Often, older substrates are likely to show signs of crumbling mortar or paint, which is why a suitable preparation material, such as the Heritage Lime Harling, is essential. The Lime Harling is ‘harled’ at the wall, creating a roughcast finish which allows the basecoat reinforcement layer to adhere to it strongly.
The Heritage Lime Harling is ideal for substrates with a low/medium salt content or if the substrate is particularly absorptive. It’s best for heritage projects because it works in unison with the rest of the system to maintain breathability. If you’re working with a substrate that has a high salt content, then we recommend the application of the Heritage Lime NaCl which will essentially just stabilise the salts and prevent them coming through to the surface.
Applying the Heritage Lime Mortar
After the Lime Harling has been left to set for a minimum of 3 days, the Heritage Lime Mortar is ready to be applied. To prepare the mortar, mix the 25kg bag is 6 litres of clean cool water and mix thoroughly with an electric paddle mix on a slow rotating setting until the mixture is completely combined. Once everything has been mixed, leave it to sit for 5 minutes and then mix again briefly before it is ready for application.
The Heritage Lime Mortar should be applied using a trowel at a maximum thickness of 2-15mm; bucket life is 2 hours after it has been mixed. You can leave the basecoat like this and apply a breathable paint or lime wash, or you can proceed to rendering.
Rendering using the Heritage Lime Render
Applying the Heritage Lime Render is very easy. Simply mix with 5 litres of water and apply to the basecoat using a plastering trowel at an approximate thickness of 10-20mm. The render creates a smooth surface and achieves a breathable, aesthetically pleasing and long-lasting finish.
The heritage system ensures that your restoration property receives the care and treatment it needs. Interested in our Heritage range? Call our sales team for technical advice and more product information!