08/08/2026
Friday’s task for Kevin and Oscar.
Render removal at this beautiful property in South Norfolk.
The render on this house is an NHL/sand render applied in 2009 which has failed for a number of reasons.
🔺Firstly, it has no (or very little) hair through it.
🔺Secondly, it is NHL and not flexible enough. It cracks as these lovely old buildings flex and move, which they most certainly do.
🔺Thirdly, the aggregate is soft or plastering sand only, so there is very little strength in it.
🔺Fourthly, the laths have been applied badly with a number of ‘straight’ joints through it. You can see an example of this above the door and below the window. The laths all end at the same points creating a weak vertical lines in the plaster which in turn leads to cracking.
The above have led to cracking, allowing moisture in, which has travelled to the base of the wall. Once behind the render, that moisture is unable to egress efficiently as the render is an NHL bound mix and less capillary active than a non-hydraulic system.
This water build up at the base of the render has lead to rotting of the laths and more failure at the base. You can see some of the laths are darker at the bottom. They’re wet/rotten.
The whole thing is an advertisement for not using NHLs in renovations or restorations.
So what’s the plan now?
🔸Removal of render and assess
🔸Repair/replace and lap laths where needed.
🔸3 coat render using non hydraulic lime. This is hotlime that we mix ourselves at our base.
The initial coat will be an earth, straw and lime base coat. The next two coats will be a haired hotlime and sand mix with a little chalk.
🔸Limewash.
Please do get in touch if you have any questions or if you’d like and advise on issues you might have with your property. We’re always happy to come out for a site visit too. 🌞
