Spotlight on lime-based render options
As we move closer to Summer, questions about rendering options always increase. Frequently, being based near Brighton, we are asked about the best renderer options for buildings on or close to the coast and whether lime renders are better than standard cement based options. As buildings in coastal regions will be exposed to high levels of moisture and salt.
Lime vs Cement
We favour lime-based renders due to their lower environmental impact; cement contributes significantly to the UK's CO2 emissions* while lime's unique ability to reabsorb CO2 during the carbonation process makes it carbon neutral over its lifecycle. However lime-based renders also offer a distinct advantage over cement-based alternatives as the two materials perform very differently. Cement is a very strong rigid non-permeable material while lime is vapour permeable and flexible, reducing the potential for cracking and allowing moisture to ingress over time. In areas prone to high levels of moisture and salt this can be an especially damaging issue.
Because cement-based renders are not breathable / vapour-permeable, trapped moisture can cause dampness problems and degrade the masonry. Additionally, if the rendering has been applied over insulation there is a risk of damage to the external insulation material.
We have found two natural lime-based renders from MGn that are water-repellant and vapour-permeable, which makes them an excellent choice for buildings in coastal areas. These are called MGN's Sanacolor and Rasante B2007 lime renders.
Our recommended lime-based renders, Sanacolor and Rasante B2007, offer unique solutions for different weatherproofing needs. Sanacolor, available in 24 pigmented colours, is a one-coat system that can be directly applied to masonry. On the other hand, the Rasante B2007 system is specifically designed to prevent moisture from penetrating into the external wall insulation (EWI), making it an ideal choice for such applications.
*Building to net zero: costing carbon in construction, House of Commons Report 2022
If you have a render project and would like to discuss lime-based render options please contact us.